The repair of a Sony STR-DG720 audio receiver in the protect mode. involves replacing power amplifier output transistors, emitter resistor and base drive resistors.
I replaced a blown 125-volt, 6.3-amp slow-blow fuze in my aging Sony STR-DE597 7.1 receiver and when I powered it up, after a few seconds it went into protect mode every time. I was stumped, but I think you may have told me how to fix it. The info and the lesson are greatly appreciated. If you're still checking this video after 5 years, thank you, NorCal715.
Thanks for this video. It was a perfect place to start in getting a Sony receiver that I pulled out of a junk pile working. Nothing like checking it after a repair and seeing a unit come right back to life!
Norcal is one of the top guy in this business such a knowledgeable and professional technician. Following him for years now. Good job my brother. Cheers!
Absolutely wonderful of you to post a video like this. Much appreciated. We are expected to just throw these out and buy new units, with a little troubleshooting and effort someone could save hundreds in replacement units. I have 3 older units handed down with this same issue, and personally have a
Excellent video! Always you are posting high quality and knowledge based videos. I know video shooting and editing is a tedious process but by this way we are helping our friends. Great effort. Regards,
LearningZone hi. I m vinay I got one receiver. Model ...STR- K870P in protection mode. In cold testing every part normal condition. Problem is after starting Showing PROTECTION. What can I do.
It's next to impossible to find useful information on this for early 2000's Sony AVR's. Thank you so much! I'm much more confident that I will be able to fix my STR-DE885's center channel now
I have an Sony SR-k750P with the same problem. Happened to find your excellent video and sure enough the exact same problem with the same readings even. Ordered replacement transistors off Amazon and will soon be trying the repair. You certainly saved this Receiver from the dump as without schematics I didn;t even no where to begin except looking for the obvious. Thank you for taking them time to share.
@@kikcodog i have the same amp but it got much worse, some problem before, a transistor almost burned, the heat compound got darker and smell very bad, even some smoke got out, but weirdly enough, re solder every transistor, put everything back, power and got sound, but then i tested the headphone connection to find any parasitic signal but suddenly, the screen showed PROTECT but before blinking, the unit went off, the transformer got killed, nothing blow yet, replaced the step down converter to power it up again, relays work but now i have no image on the VFD and i don't know what went wrong here.
I congratulate you, straight to the problem excellent explanation and proper sequence, and NO drama ... other videos do much theater for something so easy to end up confusing and frightening apprentices, thanks for your videos
MAN THIS IS A LIFE SAVER!! I HAVE A SONY STR-DH130 RECEIVER !! It is stuck in protect mode and I just so happen to have a solder gun and volt meter I'm going to fix my own receiver ASAP !! NOW I got to order the Transistors !!
Absolutely top notch - clear precise how-to. My STR-KS1300 (slimline 5.1 amp) is now showing the exact same thing. This video gives me a great place to start, and by the looks of it might fix it. the Ks1300 was working but noticed I had a different issue, as it takes random amount of button presses to get it to power on but I'd not hear that relay click but it did produce sound. Although now I get protect mode so I could be a different issue. still work checking the components you showed me though.
Thanks so much for making this video and the in depth troubleshooting explanations. I was able to get my Sony STR DN1000 AVR back up and running again thanks to your video. I had no experience with any of this and very little soldering experience. Using a $10 multimeter, I was able to find that I had a bad emitter resistor and a pair of bad output transistors. Ordered some new ones from aliexpress and carefully soldered them in and it powered up! I connected all 5 of my speakers and I found that the front right speaker sounded like it was badly blown. I then moved both front speakers from "Speaker A" to "Speaker B" and the sound is perfect again. I don't know if my "blown" front right speaker when using speaker A is due to poor quality parts from aliexpress, my poor quality soldering job, some other small resistor needing to be replaced, or something else, but I only have 5 speakers in a 7.1 channel receiver, so it's not bothering me.
I have a Sony reciever str-av570, that keeps going into protect mode intermittently, even when the reciever is off, will intermittently do relay click and amber leds on the front will glow gradually, off, and repeat till I unplug it. Back in 2003-2004(before TH-cam), I took my reciever to a authorized sony service center that did not know how to fix it, but charged me $35 to inspect device anyways. From this vid you posted, looks like a good place to start. Thanks for sharing!
Why i like this video ? Because you explain the complete diagnostic procedure... And from that i learn alot ! Thanks ! Looking forward for the next one !
I recently finished repairing a STR-DE135 with protect on symptom. Upon visual inspection, I saw two obvious issues . The driver IC701 area and the Q801 24v regulator had overheated resulting in bad solder connects and a darkening of the circuit board. IC701 did not test bad but I replaced it and c740,741 and c742. Protect still on. Next I replaced c802. Protect still on. Finally, confident that both circuits were restored to fully operational condition I replaced r740 10 ohm and Shazam ! Solid fix ! The takeaway is overheating is often caused by bad capacitors .
Thanks! I can't wait go get started on the repair. Do you have any recommendations on a reliable brand or model of receiver/amplifier, based on your experience of repairing them? Are there any to avoid or any that you'd recommend that should hopefully outlast others?
Hi! Thank you very much for this video. My Sony STR-KM3 (Argentina model) is turning off right after power on, displaying a "USB FAIL" error message, despite the model DOES NOT having any USB connector? (I have once repaired the same model, but with USB. The problem was a faulty relay (RY901)). Any suggestion or hint? Thank you.
Best video yet . that's explain and really broke down the process of repairing your receiver...... I ready to buy my pieces and fix my sony and denon receivers.
Thankyou helped me repair my Sony STR-DH590 same topology just 2 channels less, mirrored you step by step found bad solder joints, Seams to be a sony issue with bad solder due to heating and cooling, but thankyou again.
These old sonys have the Vacuum Fluorescent Displays(VFD) that I think look beautiful and don't exist as much on newer receivers making these a very beautiful receiver to continue to keep functioning. Another thing I've been a fan of on Sonys is that they take a signal and can be set to put it back out without effects as clean as the signal they were given except amplified for speakers which is great if your DAC or something is an external device that wants to do it's own effects/has better effects.
I have to say that your videos and wonderful instruction have been invaluable to me. I had been reading/studying and doing little "experiments" for several years. Your videos took me to the next level and I am really enjoying repairing now. Thanks again! Just a quick question if you would; I have a Sony receiver that I am working on currently. Power supply is good, power transistors are good, emmitter resistors are good. Something is dragging down the B+ rail voltage by approx 20v then quickly goes into protect mode. I think it is a shorted driver IC. Is it safe for the circuit to take the chip out of circuit to see if the B+ rail normalizes?
Good communicator, well explained fault finding, loved your tip with the dental pick.............Liked, subscribed, and looking for more. Ray H. from the U.K.
Hi there. wondering if you can help me! i have a sony str-565 with distortion on the left hand output. i think is the preamp because i can here it on the headphones to. but have no diagrams and i had forgotten how to check some circuits sins i graduated electronic technician and never did some actual repairs. thank you! and excellent video
an update on that HK receiver i had that shut off, it was a bad Center channel transistor. After taking it out, it worked! i got sound and it stayed on. Your video here helped me troubleshoot it! I sold it and the guy is gonna replace the bad parts in it.
As a footnote, I did some voltage checks with the unit powered up, looking at the 6 ic's mounted to the main heatsink. Base idle voltage on two of the three 2488's tested at +1.15v and -1.05v on the 1620's. The 2488 collectors tested +52v and 1620's at -52v. Emitter outputs tested at 0v. On the last pair of ic's (nearest the front of the receiver) the 2488 had -51v base, +52v collector and -50v emitter. The 1620 tested at -51v base, -52v collector and -50v emitter. I tripple checked them for shorts and both tested fine with all diode junctions intact. What would allow 50 volts to show on the base side of the transistors other than a short? I believe the base voltages are effectivly "turning on" the transistors and thru-putting 51 volts (less the v drop thru the diodes) ending up as 50v on the emitters. Hmmm.... Again, thanks ahead of time for any help you or your subscribers may be able to lend to my troubleshooting. Reguards, Jim
Parabéns pelo ótimo vídeo. Vou tentar consertar o meu também, um SRT-DE885 que já está parado há mais de 2 anos pelo mesmo problema. Obrigado. Congratulations for the great video. I will try to fix my receiver too, an SRT- DE885 it is stopped about two years with this same problem. Thank you very much.
Great video, thank you! I have an STR-DE597 that goes into Protect mode, but seemingly only when it's cold. Can't wait to get stuck in. Could this also be a reason for almost no bass coming from one side? I have swapped speakers and inputs to no avail.
I have similar Sony Muteki 1510 Watts receiver. It looks same as this unit from inside and outside. But this is 6.2 channel amplifier. I have issue with center channel which have some noise and sound is not clear. Rest all channels are working fine. I did check the center speaker in other channel and speaker is good. I strongly suspect the noise is being introduced in center channel. Please guide me how to troubleshoot this issue. Which all components could be problem?
Great Video!!! I'm just wondering... I have a Sony DVD Receiver AVD-K800P and it stopped working a couple of years ago and just today I decided to give it a go. Based on what I'm seeing on the screen (which appeared blank those years before) everything appears to be working well, the only problem is I cant hear anything, checked and the speakers are working. Any thoughts on what could be the problem? I suspect its audio related. Also do you have any videos for my model though not related to my specific problem? Thanks!
Great video!I have the same problem with SONY HT-DDW840. There are five big white noble resistors. When I test the central lead with DC voltage range I get the following readings: 3.383v on four of resistors and 0.52.4v on one of them.Based on this, can I conclude that this fifth one is damaged?
hello there, very nice and detailed video! I have model STR-DE695 which has same symptoms as yours - goes out to protect on powering up. I did all same as you instructed, but my output transistors and emiter resistors readings are fine. I also did resolder drivers. What I find strange is that one element on digital board goes very hot while amp is blinking PROTECT, but its voltage readings are fine.... So, now im confused... What else should I check? Many thanks!
Hey, Great video. I am trying to use these steps to help determine my issue with a NAD 7400 PE receiver. I checked the emitter resistors (white) and found one out of spec with an ohmmeter. It was open. During the voltage check I found that that one and another emitter resistor was out of range. Both were reading 52.0v. I do have a question on the output transistors. When I try your diode check my results are different than yours. I get readings in forward and reverse bias. The readings are between 0.5-0.7v. Does this seem normal for output transistors? I have two b940a and two d1264a.
Great Video,I have this same STR-DG720 has been great,all of a sudden the 2 front speakers are very low volume,all others are ok.Even on 2 channel setting,I have to crank volume to like 40 or 50 to get any kind of volume on the 2 front speakers.It's just the 2 front speakers.All others are fine.Have you seen anything like this before on this receiver? Any idea's would be greatly appreciated.The 2 front speakers work,but very low volume.Speakers,wiring,and connections all good.Just noticed this a few days ago.All speaker lights on front panel are lit.Thankyou
I really appreciate this video as I have a STR DE445 that is going into protect mode after working on it. I screwed something up as to start I only had a quiet right channel but everything else seemed OK. I took out all the power transistors and checked them out of circuit which seemed like they were OK did not notice any shorts but after a lousy solder job putting back it together it goes into protect now. I need to take it back apart and do it right checking emitter resistors and transistors properly the way you showed us and maybe I can resurrect it? I really needed your guidance in this video, thanks again for taking the time to produce this it will help me tremendously.
thanks for the great video. I have an old sony STR-D565 that has gone on protect mode recently. I didnt use it for about a year but it was working great, it did over heat and go on protect mode on a couple of house parties I had. I pulled it apart and did everything you showed, it all checked out good, what would you recommend to check afterwards? Thanks!
I have the protect msg on my HK AVR130, disconnected all spkrs except main R and L and it worked for a few hrs, now I get the protect msg and it shuts down every time. Works fine with Headphone jack. Should I follow the same procedure you have here?
Good day. I followed this video of yours and it's helped me alot, so thank you for that. But what I would like to ask and need some help with is a NAD T743. What it does is that it's stuck in the standby mode. Could you please just gie me an idea of where to start. Regards Cedric
awesome this is the first vid i watched of you...and I'm happy to have found you!! ? I have a de335 with same issue...i guess i need a multimeter first!
Thanks so much for this video. This fixed my issue on an STR DG-1000. The protect mode is now off, after replacing both transistors and the dual resistor. However, I now have distortion/static in that replaced right channel. I've tried new speakers/amps/etc.. so I'm confident its in the amp. Any idea what might be causing the distortion/static?
Great! Question, I had disassembled my str-dh520 (very similar) before I found this video and had tested all vrms and op amps and found the lm7805 to be faulty. I swapped it and reassembled and now I hear a solenoid click and I get no power up. I checked the voltage on the 7905 and 7805 and 7v one (forgot the vrm number) and they all check good (-5v,5v,7v respectively). Where should I proceed from here? I've rechecked all connections multiple times. Also will the unit power up without the hdmi board? I have to remove that every time to get to the vrms.
Great video. I'm having a different issue with my AVR, but I can't find any troubleshooting on my problem. I have a Sony STR-DG720 and I am having speaker calibration issues. I attempt to calibrate and receive an error code 12, which means the speakers are not detected. Do I need a specific speaker connected and/or all the speakers connected? I will only be using it in 2 channel mode, only a front left and front right speaker. Have you experienced this before?
very nice video I think I may have the info for what I need on my older amp I have a 70s pioneer sa 8500 it keeps going in and out of safety cut off when you turn it on it will take forever to click then it will click right back off if left on for a few mins it will cut off and on this is without a load or anything on the inputs after watching your vid im thinking my emitter resistors might be bad as well as possibly a few of the transistors
I have a Sony DA80es with the Protect message problem. While not the same as the one in your video I followed your procedure. There are two emitter resisters showing 24 ohms when power is on and all the rest are very low voltages. But the component that emitter resister connects to has 5 leads on it. The component is a Sony NEP250. Could you tell me how I can check this like you did the transistor on the unit in this video. Thank you!
You mentioned the danger the large capacitors pose, but you still worked on the opened unit while powered on with no gloves or anything. How do you know its safe to work on? I want to try to fix my Sony STR-DE545 but I don't want to get a shock. Also, is it possible that a receiver can short out and go to Protect mode simply because of dust? My receiver is 16 years old. And looks dusty inside. I have not taken the cover off yet. Thanks.
Nicely done Steve; i have a sony N9000ES with the same problem, it turns on some times and works fine for hours together but some times it goes to protector mode when i switch on. I checked the output NEP250/NEN250 five leg transistors and 0.22K (2Wx2) Resistors which are fine in all channels. What could be the reasons.
Really enjoyed watching this, looking for a solution though my Sony STR-DA50 ES isn't in 'protect mode'. Nobody on SONY community talking about these old (1997) models. Haven't used since 2008 then last week just plugged it in, and tape / phone/ CD all was working , then nothing. Display working, can hear the A/ B spkrs switching, but no audio signal from tape/ CD or phone monitorable , even at the headphone. Any ideas? All sources and headphones checked and working.
Hi, thanks for a informative video. I wonder if you could help or point me in the right direction, have a Sony STR-DG910 which has some issues... If you plug it in, you can turn it on using the power button on the front panel, and you can turn it off (standby) from the same power button, but it won’t turn back on again, if your pull the plug out for a second and re-power it, it will allow you to turn it on again, but it goes “dead” again after you put it into standby again.... the IR remote is also non responsive, all functions. I have checked signals with my scope and can are getting all the way onto the “digital board. The front panel knobs work off the same IC, and they respond when the radio is on.... like vol/input/tone etc. so it means that ic must be running. It’s almost like when the chip goes into sleep, it doesn’t want to wake up, unless you remove the power for a short time. Any help would be greatly appreciated. Kind regards
Do you have any suggestions on tracking down popping and crackling sounds coming from only one channel of a Sony Receiver (center to be exact)? Although my Sony amp is not same (has 9.2, with bi-amplification option on the front channels), I'm sure you would have an idea. I followed your process of diagnosing a receiver (this particular problem), and it doesn't seem to be the issue for me (although I realize this amp was in protect mode). Your understanding and explanations are very clear and precise, and I wish you had (if I can request) a video of common receiver/amplifier problems, and your process to diagnosis them (I realize you have a few videos with a few of the problems). Thanks for any help! Btw, I have a STR-Da2800es
Hey there, nice video, im glad i found it since i have the same problem with my sony STR-DE415. I already got the new transistors, but i just cant find that dual emitter resistor in any webshop at my country, and postage from US takes months to arrive to EU. Is there any way i can substiute that part?
Hi . I have the sony STR-DH800. Over time the master volume has needed to be increased to MAX to listen to at normal pleasent levels. It all sounds good, but its cranked up full wack now. The protection circuit sometime fires when I turn it on at these levels. It looks very similar to unit on your vid. What should I be looking at for repair. Kind regards. Kenny
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8 years later and your still helping people 😍
Enjoyed watching the entire video. I like the feeling of success when there's a fixed equipment after a repair..
I replaced a blown 125-volt, 6.3-amp slow-blow fuze in my aging Sony STR-DE597 7.1 receiver and when I powered it up, after a few seconds it went into protect mode every time. I was stumped, but I think you may have told me how to fix it. The info and the lesson are greatly appreciated. If you're still checking this video after 5 years, thank you, NorCal715.
Thanks for this video. It was a perfect place to start in getting a Sony receiver that I pulled out of a junk pile working. Nothing like checking it after a repair and seeing a unit come right back to life!
Keep looking around. That's where mines going
Norcal is one of the top guy in this business such a knowledgeable and professional technician. Following him for years now. Good job my brother. Cheers!
Nicely done Steve; When logic is deployed, troubleshooting becomes easier.
Absolutely wonderful of you to post a video like this. Much appreciated. We are expected to just throw these out and buy new units, with a little troubleshooting and effort someone could save hundreds in replacement units. I have 3 older units handed down with this same issue, and personally have a
Excellent video! Always you are posting high quality and knowledge based videos. I know video shooting and editing is a tedious process but by this way we are helping our friends. Great effort. Regards,
LearningZone hi.
I m vinay
I got one receiver. Model ...STR- K870P in protection mode. In cold testing every part normal condition. Problem is after starting
Showing PROTECTION.
What can I do.
Man U are one of the best I’ve seen with explaining how to work these
Another great repair video. I have 2 Sony receivers that go into protection mode. Now I am motivated to fix them.
My Sony str de685 display light is not Comeing on the store comes on but the display light don't how do I fixs that
It's next to impossible to find useful information on this for early 2000's Sony AVR's. Thank you so much! I'm much more confident that I will be able to fix my STR-DE885's center channel now
Excellent video. Well explained all details. Nice to see a professional skills to avoid recycling in electronics.
I have an Sony SR-k750P with the same problem. Happened to find your excellent video and sure enough the exact same problem with the same readings even. Ordered replacement transistors off Amazon and will soon be trying the repair. You certainly saved this Receiver from the dump as without schematics I didn;t even no where to begin except looking for the obvious. Thank you for taking them time to share.
Did it work?
Unfortunately, No. It must have been something more.
@@kikcodog i have the same amp but it got much worse, some problem before, a transistor almost burned, the heat compound got darker and smell very bad, even some smoke got out, but weirdly enough, re solder every transistor, put everything back, power and got sound, but then i tested the headphone connection to find any parasitic signal but suddenly, the screen showed PROTECT but before blinking, the unit went off, the transformer got killed, nothing blow yet, replaced the step down converter to power it up again, relays work but now i have no image on the VFD and i don't know what went wrong here.
I congratulate you, straight to the problem excellent explanation and proper sequence, and NO drama ...
other videos do much theater for something so easy to end up confusing and frightening apprentices, thanks for your videos
MAN THIS IS A LIFE SAVER!! I HAVE A SONY STR-DH130 RECEIVER !! It is stuck in protect mode and I just so happen to have a solder gun and volt meter I'm going to fix my own receiver ASAP !! NOW I got to order the Transistors !!
Your video helped me to fix a dead home theater receiver. THANK YOU!
Absolutely top notch - clear precise how-to. My STR-KS1300 (slimline 5.1 amp) is now showing the exact same thing. This video gives me a great place to start, and by the looks of it might fix it. the Ks1300 was working but noticed I had a different issue, as it takes random amount of button presses to get it to power on but I'd not hear that relay click but it did produce sound. Although now I get protect mode so I could be a different issue. still work checking the components you showed me though.
Thanks so much for making this video and the in depth troubleshooting explanations. I was able to get my Sony STR DN1000 AVR back up and running again thanks to your video. I had no experience with any of this and very little soldering experience. Using a $10 multimeter, I was able to find that I had a bad emitter resistor and a pair of bad output transistors. Ordered some new ones from aliexpress and carefully soldered them in and it powered up!
I connected all 5 of my speakers and I found that the front right speaker sounded like it was badly blown. I then moved both front speakers from "Speaker A" to "Speaker B" and the sound is perfect again.
I don't know if my "blown" front right speaker when using speaker A is due to poor quality parts from aliexpress, my poor quality soldering job, some other small resistor needing to be replaced, or something else, but I only have 5 speakers in a 7.1 channel receiver, so it's not bothering me.
I have a Sony reciever str-av570, that keeps going into protect mode intermittently, even when the reciever is off, will intermittently do relay click and amber leds on the front will glow gradually, off, and repeat till I unplug it. Back in 2003-2004(before TH-cam), I took my reciever to a authorized sony service center that did not know how to fix it, but charged me $35 to inspect device anyways. From this vid you posted, looks like a good place to start. Thanks for sharing!
The best video on repair so far. Thank you very much.
This video is exactly what I was looking for, many thanks your videos are great.
Why i like this video ? Because you explain the complete diagnostic procedure... And from that i learn alot ! Thanks ! Looking forward for the next one !
I recently finished repairing a STR-DE135 with protect on symptom. Upon visual inspection, I saw two obvious issues . The driver IC701 area and the Q801 24v regulator had overheated resulting in bad solder connects and
a darkening of the circuit board. IC701 did not test bad but I replaced it and c740,741 and c742. Protect still on.
Next I replaced c802. Protect still on. Finally, confident that both circuits were restored to fully operational condition I replaced r740 10 ohm and Shazam ! Solid fix ! The takeaway is overheating is often caused by bad
capacitors .
Thank you, once again another cracking lesson. Keep up the good work
I fixed a doomed STR-DG520 with this tutorial this is gold! 105Ohm is within tolerance tho I found one that read 2MOhm instead of 100
nice one sir your the best technician i've ever seen your my idol because i learn a lot from you thanks
Thanks! I can't wait go get started on the repair. Do you have any recommendations on a reliable brand or model of receiver/amplifier, based on your experience of repairing them? Are there any to avoid or any that you'd recommend that should hopefully outlast others?
Thanks for all explanations. I need to watch this video again :-)
Another very informative tutorial.Thank you.
Simply Lovely. Very impressive explanations reflect the work experience.
Hi! Thank you very much for this video.
My Sony STR-KM3 (Argentina model) is turning off right after power on, displaying a "USB FAIL" error message, despite the model DOES NOT having any USB connector?
(I have once repaired the same model, but with USB. The problem was a faulty relay (RY901)).
Any suggestion or hint?
Thank you.
Very informative video. You you tube producers are really helping teach people like me....well some of you are. Peace
Very good documentary and very informative lecture, love see more.
Excellent Video, Great effort, let us look into actual remedy information rather than extra sounds,
Best video yet . that's explain and really broke down the process of repairing your receiver...... I ready to buy my pieces and fix my sony and denon receivers.
Excellent work, this is a very helpful video and the commentary really good -Thanks man!
Thankyou helped me repair my Sony STR-DH590 same topology just 2 channels less, mirrored you step by step found bad solder joints, Seams to be a sony issue with bad solder due to heating and cooling, but thankyou again.
These old sonys have the Vacuum Fluorescent Displays(VFD) that I think look beautiful and don't exist as much on newer receivers making these a very beautiful receiver to continue to keep functioning.
Another thing I've been a fan of on Sonys is that they take a signal and can be set to put it back out without effects as clean as the signal they were given except amplified for speakers which is great if your DAC or something is an external device that wants to do it's own effects/has better effects.
Thanks for a great video on theSony!
thank you very much . I am an amateur and you helped me a lot with your video to repair a sony str-de595. Good for you
I have to say that your videos and wonderful instruction have been invaluable to me. I had been reading/studying and doing little "experiments" for several years. Your videos took me to the next level and I am really enjoying repairing now. Thanks again! Just a quick question if you would; I have a Sony receiver that I am working on currently. Power supply is good, power transistors are good, emmitter resistors are good. Something is dragging down the B+ rail voltage by approx 20v then quickly goes into protect mode. I think it is a shorted driver IC. Is it safe for the circuit to take the chip out of circuit to see if the B+ rail normalizes?
thank you so much of your very informative videos.
Good communicator, well explained fault finding, loved your tip with the dental pick.............Liked, subscribed, and looking for more.
Ray H. from the U.K.
Thanks for an informative and interesting video.
Hi there. wondering if you can help me! i have a sony str-565 with distortion on the left hand output. i think is the preamp because i can here it on the headphones to. but have no diagrams and i had forgotten how to check some circuits sins i graduated electronic technician and never did some actual repairs. thank you! and excellent video
an update on that HK receiver i had that shut off, it was a bad Center channel transistor. After taking it out, it worked! i got sound and it stayed on. Your video here helped me troubleshoot it! I sold it and the guy is gonna replace the bad parts in it.
Man, you are an electric surgeon 😷. Ty for this video.
Great vid! Question, would Kapton tape substitute for mica to insulate the fets???
Thank you very informative and to the point.
appreciated your videos and thanks for the hard work .
As a footnote, I did some voltage checks with the unit powered up, looking at the 6 ic's mounted to the main heatsink. Base idle voltage on two of the three 2488's tested at +1.15v and -1.05v on the 1620's. The 2488 collectors tested +52v and 1620's at -52v. Emitter outputs tested at 0v.
On the last pair of ic's (nearest the front of the receiver) the 2488 had -51v base, +52v collector and -50v emitter. The 1620 tested at -51v base, -52v collector and -50v emitter. I tripple checked them for shorts and both tested fine with all diode junctions intact. What would allow 50 volts to show on the base side of the transistors other than a short? I believe the base voltages are effectivly "turning on" the transistors and thru-putting 51 volts (less the v drop thru the diodes) ending up as 50v on the emitters. Hmmm....
Again, thanks ahead of time for any help you or your subscribers may be able to lend to my troubleshooting. Reguards, Jim
Awesome video. Very clear. Are there any steps you take to make sure the filter caps are discharged or is there a discharge circuit on the unit?
Thank you for explaining how to test a transistor. I've been watching videos and everybody does it but no explanation gees.
Thanks Bro!! Great lesson and saved my sony!!
Parabéns pelo ótimo vídeo. Vou tentar consertar o meu também, um SRT-DE885 que já está parado há mais de 2 anos pelo mesmo problema. Obrigado.
Congratulations for the great video. I will try to fix my receiver too, an SRT- DE885 it is stopped about two years with this same problem. Thank you very much.
Great video, thank you! I have an STR-DE597 that goes into Protect mode, but seemingly only when it's cold. Can't wait to get stuck in.
Could this also be a reason for almost no bass coming from one side? I have swapped speakers and inputs to no avail.
I have similar Sony Muteki 1510 Watts receiver. It looks same as this unit from inside and outside. But this is 6.2 channel amplifier. I have issue with center channel which have some noise and sound is not clear. Rest all channels are working fine. I did check the center speaker in other channel and speaker is good. I strongly suspect the noise is being introduced in center channel. Please guide me how to troubleshoot this issue. Which all components could be problem?
Great explanations and instructions.
Congratulations, i was very helpful your lesson, thank you very much.
That solder melted really fast and clean, what temperature did you use on the soldering iron?
Thanks for doing the videos again
I’m still loving this video
Great Video!!!
I'm just wondering... I have a Sony DVD Receiver AVD-K800P and it stopped working a couple of years ago and just today I decided to give it a go. Based on what I'm seeing on the screen (which appeared blank those years before) everything appears to be working well, the only problem is I cant hear anything, checked and the speakers are working.
Any thoughts on what could be the problem? I suspect its audio related.
Also do you have any videos for my model though not related to my specific problem?
Thanks!
Great video!I have the same problem with SONY HT-DDW840. There are five big white noble resistors. When I test the central lead with DC voltage range I get the following readings: 3.383v on four of resistors and 0.52.4v on one of them.Based on this, can I conclude that this fifth one is damaged?
hello there,
very nice and detailed video!
I have model STR-DE695 which has same symptoms as yours - goes out to protect on powering up.
I did all same as you instructed, but my output transistors and emiter resistors readings are fine.
I also did resolder drivers. What I find strange is that one element on digital board goes very hot while amp is blinking PROTECT, but its voltage readings are fine.... So, now im confused... What else should I check?
Many thanks!
Hey,
Great video. I am trying to use these steps to help determine my issue with a NAD 7400 PE receiver. I checked the emitter resistors (white) and found one out of spec with an ohmmeter. It was open. During the voltage check I found that that one and another emitter resistor was out of range. Both were reading 52.0v. I do have a question on the output transistors. When I try your diode check my results are different than yours. I get readings in forward and reverse bias. The readings are between 0.5-0.7v. Does this seem normal for output transistors? I have two b940a and two d1264a.
Great Video,I have this same STR-DG720 has been great,all of a sudden the 2 front speakers are very low volume,all others are ok.Even on 2 channel setting,I have to crank volume to like 40 or 50 to get any kind of volume on the 2 front speakers.It's just the 2 front speakers.All others are fine.Have you seen anything like this before on this receiver? Any idea's would be greatly appreciated.The 2 front speakers work,but very low volume.Speakers,wiring,and connections all good.Just noticed this a few days ago.All speaker lights on front panel are lit.Thankyou
I really appreciate this video as I have a STR DE445 that is going into protect mode after working on it. I screwed something up as to start I only had a quiet right channel but everything else seemed OK. I took out all the power transistors and checked them out of circuit which seemed like they were OK did not notice any shorts but after a lousy solder job putting back it together it goes into protect now. I need to take it back apart and do it right checking emitter resistors and transistors properly the way you showed us and maybe I can resurrect it? I really needed your guidance in this video, thanks again for taking the time to produce this it will help me tremendously.
thanks for the great video. I have an old sony STR-D565 that has gone on protect mode recently. I didnt use it for about a year but it was working great, it did over heat and go on protect mode on a couple of house parties I had.
I pulled it apart and did everything you showed, it all checked out good, what would you recommend to check afterwards?
Thanks!
Thank you very much for your explanations. I hope i can repair my “Protected” Sony STR-DE597.
Once again a good repair video. The title is a bit funny though. Protest-mode :-)
I have the protect msg on my HK AVR130, disconnected all spkrs except main R and L and it worked for a few hrs, now I get the protect msg and it shuts down every time. Works fine with Headphone jack. Should I follow the same procedure you have here?
thanks man for your time, your video is very helpful
Good day. I followed this video of yours and it's helped me alot, so thank you for that. But what I would like to ask and need some help with is a NAD T743. What it does is that it's stuck in the standby mode. Could you please just gie me an idea of where to start.
Regards
Cedric
awesome this is the first vid i watched of you...and I'm happy to have found you!! ? I have a de335 with same issue...i guess i need a multimeter first!
Very informative awesome diy video! thanks!!
Nice and very professional!
nice video
thanks man this was very helpful
Thanks so much for this video. This fixed my issue on an STR DG-1000. The protect mode is now off, after replacing both transistors and the dual resistor. However, I now have distortion/static in that replaced right channel. I've tried new speakers/amps/etc.. so I'm confident its in the amp. Any idea what might be causing the distortion/static?
Great video Steve....
hey John whats up in Austin? have not heard anything in a while from you, since the tower climbing video some years ago!. still at 3M????
Hi Steve. Yes still there but not quite as long you been with PL. You have quite a lot of really good instructive videos. Nice job.
Great! Question, I had disassembled my str-dh520 (very similar) before I found this video and had tested all vrms and op amps and found the lm7805 to be faulty. I swapped it and reassembled and now I hear a solenoid click and I get no power up. I checked the voltage on the 7905 and 7805 and 7v one (forgot the vrm number) and they all check good (-5v,5v,7v respectively). Where should I proceed from here? I've rechecked all connections multiple times. Also will the unit power up without the hdmi board? I have to remove that every time to get to the vrms.
Thank you so much for this video.
Good job - though have to say I was a little disappointed to find out that it didn't have a Protest mode after all!
You are a good teacher sir!! I have a onkyo 646 that has no sound 🔊 where sound look and what should I start trouble shooting? Thanks
Great video. I'm having a different issue with my AVR, but I can't find any troubleshooting on my problem. I have a Sony STR-DG720 and I am having speaker calibration issues. I attempt to calibrate and receive an error code 12, which means the speakers are not detected. Do I need a specific speaker connected and/or all the speakers connected? I will only be using it in 2 channel mode, only a front left and front right speaker. Have you experienced this before?
very nice video I think I may have the info for what I need on my older amp I have a 70s pioneer sa 8500 it keeps going in and out of safety cut off when you turn it on it will take forever to click then it will click right back off if left on for a few mins it will cut off and on this is without a load or anything on the inputs after watching your vid im thinking my emitter resistors might be bad as well as possibly a few of the transistors
I have a Sony DA80es with the Protect message problem. While not the same as the one in your video I followed your procedure. There are two emitter resisters showing 24 ohms when power is on and all the rest are very low voltages. But the component that emitter resister connects to has 5 leads on it. The component is a Sony NEP250. Could you tell me how I can check this like you did the transistor on the unit in this video. Thank you!
Very good, clean manutention and correct....
You mentioned the danger the large capacitors pose, but you still worked on the opened unit while powered on with no gloves or anything. How do you know its safe to work on? I want to try to fix my Sony STR-DE545 but I don't want to get a shock.
Also, is it possible that a receiver can short out and go to Protect mode simply because of dust? My receiver is 16 years old. And looks dusty inside. I have not taken the cover off yet. Thanks.
Nicely done Steve; i have a sony N9000ES with the same problem, it turns on some times and works fine for hours together but some times it goes to protector mode when i switch on. I checked the output NEP250/NEN250 five leg transistors and 0.22K (2Wx2) Resistors which are fine in all channels. What could be the reasons.
Thank you for the lesson.
Really enjoyed watching this, looking for a solution though my Sony STR-DA50 ES isn't in 'protect mode'. Nobody on SONY community talking about these old (1997) models. Haven't used since 2008 then last week just plugged it in, and tape / phone/ CD all was working , then nothing. Display working, can hear the A/ B spkrs switching, but no audio signal from tape/ CD or phone monitorable , even at the headphone. Any ideas? All sources and headphones checked and working.
Hi, thanks for a informative video.
I wonder if you could help or point me in the right direction, have a Sony STR-DG910 which has some issues...
If you plug it in, you can turn it on using the power button on the front panel, and you can turn it off (standby) from the same power button, but it won’t turn back on again, if your pull the plug out for a second and re-power it, it will allow you to turn it on again, but it goes “dead” again after you put it into standby again.... the IR remote is also non responsive, all functions. I have checked signals with my scope and can are getting all the way onto the “digital board.
The front panel knobs work off the same IC, and they respond when the radio is on.... like vol/input/tone etc. so it means that ic must be running.
It’s almost like when the chip goes into sleep, it doesn’t want to wake up, unless you remove the power for a short time.
Any help would be greatly appreciated. Kind regards
Your video is very didactic and useful, thanks.
Marvellous work. Any sprays available in market to protect PCBs from moisture and other contaminants place update
i have the exact stereo but the menu selection ir volume does not work for some reason
Do you have any suggestions on tracking down popping and crackling sounds coming from only one channel of a Sony Receiver (center to be exact)? Although my Sony amp is not same (has 9.2, with bi-amplification option on the front channels), I'm sure you would have an idea. I followed your process of diagnosing a receiver (this particular problem), and it doesn't seem to be the issue for me (although I realize this amp was in protect mode). Your understanding and explanations are very clear and precise, and I wish you had (if I can request) a video of common receiver/amplifier problems, and your process to diagnosis them (I realize you have a few videos with a few of the problems). Thanks for any help!
Btw, I have a STR-Da2800es
Hey there, nice video, im glad i found it since i have the same problem with my sony STR-DE415. I already got the new transistors, but i just cant find that dual emitter resistor in any webshop at my country, and postage from US takes months to arrive to EU. Is there any way i can substiute that part?
Where do you get these parts from? I would like fix my protector mode issues myself, but have no clue where to get the replacement parts...
Hi . I have the sony STR-DH800. Over time the master volume has needed to be increased to MAX to listen to at normal pleasent levels. It all sounds good, but its cranked up full wack now. The protection circuit sometime fires when I turn it on at these levels. It looks very similar to unit on your vid. What should I be looking at for repair. Kind regards. Kenny