I had the same receiver a few years ago. The light bulbs for the tuner were glitching (bad solder joint on the connector) and the balance pot was scratching, which resulted in no right channel. Apart from that the receiver was fine, no bad caps and needed no adjustments
Great video, and diagnostic skills. I love the way you explain things. This receiver has some hours on it, that's for sure. I'm also active in the same field as you, fixing consumer electronics as a profession. My focus is on vintage audio. Mainly upgrading and fixing amps and cd players. Currently i'm working up the courage to start a full restoration on a pm 665 VXI. I'm a great fan of hk amps of this era, as they have dc coupling, and very few coupling caps. I did a pm655 7years ago, and recenly that cliënt brought the unit back for some small upgrades and repair. I was reminded again how good these units sound after a full and good restoration, and bought a pm665vxi on Marketplace for my personel collection. Congrats on the 10.000 subs m8, i'm just surprised it's not a 100K subs (yet😂). Ported over from Xray T's channel some years ago. Also i like the calm way you do and explain things. Without drama, and with knowlege. All the best, and cheers from the Netherlands.
Thanks and welcome to the channel. Hopefully you'll find something helpful for you here. Maybe one day I'll find a 665 Vxi for myself, I'd love to listen to that one fersure.
I have a 665VXI too that needs a repair. Powers up but no sound. I’m a novice with regard to making repairs. Any thoughts on where to begin or likely culprit?
@@dennismeehan8189 Check if your switch for seperating pre and main amp is in the right position. Press it on and off for 10 times first with the amp switched off. Then try it.
Trevor.............You are a very good teacher/instructor (for a Canadian-just teasing), I always watch every minute. Important to people like myself that have an addiction to 1976-1979 Stereo Equipment and back in my early days of buying fell victim to ill legitimate Stereo repair charging a fortune and doing little to nothing. No 6 ohm setting, have many 6 ohm speakers. Was enjoying that Blonde tune. Those dreaded green TK caps Room temp 77 F What if it is 75 WTH. 96C = 205F That is pretty damn hot, fry an egg on that.
The hk880 vxi is rated at 60 wpc but H/K rates their power output conservatively. 71.58 wpc is great but not many people will run that receiver at full output. The power transformer seems a bit anemic and small for what it is handling but just "adequate". The excessive voltage sag on the power transformer is a bit concerning but I guess it is ok and will hold out, otherwise the engineers and manufacturer, Shin-Shirasuna wouldn't have released that design into production. If you ever come across the hk990 vxi (90 wpc) at a good price, grab it. That receiver really kicks.
Congrats Trevor! I've had a rash of bad leads lately and it drives me nuts. Stupid rabbit holes I've travelled only to find out I was way off. Grrrr. I have two of the Vxi integrateds. 640 and the big dual transformer 665. The 640 is a little sweety with great sound and unfortunately the 665 has a cracked input board which I've been trying to repair but no luck. I'll get back to it some day.
HK’s of this age are great sound amplifiers but always check the solder joints. Wetter it’s this series of receivers or the PM6xx and 6xxx series you can always find plenty of bad solder joints. Especially around transistors that get hot. Oh, and not to mention some series of TK caps, I have the idea that some are even worse then china caps.
This must be a stereo music power amplifier. For the intermediate option between Class AB and Class A amplification modes, selecting the appropriate quiescent current of the final power transistor can make the sound quality better than Class AB and close to Class A while maintaining the appropriate heat generation. The appropriate quiescent current is probably between 30mA and 80mA, so the value marked on this machine is close to this value. Of course, the drive stage current also needs to be coordinated. For non-Class A amplifiers, the voltage amplifier stage, drive stage, and power stage all have a suitable current value. Thank you for sharing this maintenance video. I am an electronic audio enthusiast, not an expert. I am a learning person. I express some personal opinions that may not be mature based on what I know. I don’t understand English, so this is translated into English through translation software. Thank you!
Hello Trevor -- Just Subscribed about a month or so ago -- Been binging on your videos. An Old tube radio guy & have a couple of Nice Pioneer receivers to get running. Trying to find schematics has been hard for me. I never see you tubers complain though. Can You tell me what's Your Go-To source when you need a Schematic. Your Videos Have Been Particularly helpful understanding how solid state works. Thank You in advance.
Hi Lloyd and welcome to the channel. I find most of my schematics at HiFiEngine and VinylEngine dot com. I also find a few with just a search with make, model and the words "service manual"
@@TrevorsBench Thanks so much for getting back to me. I did ask Aiden from A-H fix-it He mentioned HiFiEngine but stated "But I hear they're not taking new users. I don't know where else to go unfortunately." I know I can get some with Capacitors Kits & some Owners manuals. I will try The others & searches You mentioned also. Definitely a Big Help. Thank You
@@lloydgreen4091 Interesting they would suspend creating new accounts, I didn't know this. I've been using a search engine like Google to find service manuals with some success
It attenuates low frequencies like 20Hz and below. This is useful for the phono input only. Very low frequencies can come through from the turntable base and can cause feedback or noticeable noises like thumps or booming from the platter as the stylus rides the vinyl groove. These low frequency noises can come from things like walking across a room or from the turntable picking up bass note vibrations from the table it's sitting on and can sound quite boomy and annoying. A good solid platform for your turntable is best for reducing these noises. Some turntable manufacturers made the turntable base to have a lot of mass to prevent these noises from being picked up. Some cheap turntables used a molded plastic base and can actually resonate in the 50Hz to 200Hz range which causes noticeable feedback and noise at the resonate frequency
@@TrevorsBench Thank you for explanation Trevor I never knew what that was for. I learn something new every day from your channel. I have a Technics SL-D2 and it a heavy one so that helps for what you are describing and I also have a Technics SL1200 which is even heavier than the SL-D2
I've been putting lots of thought lately into how I can sell off some of my growing collection and make it easy for both me and people that are interested. Ebay is out of the question and am looking for better alternatives. I've had some bad experiences shipping items so I want to avoid that if possible but I know I will have to ship regardless. I'm open to hearing some ideas from you guys on how to make this happen
Fashioning end caps out of polyethylene or polypropylene is the best way to ship. Close cell bubble wrap and peanut should only be used for taking up room where the product might shift or used to buffet impact should density of end caps be too high. Additionally: I'd run up a trial ballon where commenting at the end of the video, whether for sale, along with your email address. Just my two cents worth... and enjoy your Friday night vids.
Is there a way of messaging you privately? I may want to donate a piece of test equipment if you think you would use it. I'm in the US so I'd need to know how to ship without unnecessary charges beyond postage.
@@mdzacharias Yeah. TH-cam now hides that information on my channel page. If you look at my channel page, where I describe my channel there is a link tagged on the end of the sentence that says .....more If you click on that it open the ABOUT window with my info
... it is embarrassing to call yourself an electronics technician ... guessing, the functions of chips, detecting their use without consulting any parts catalogue, just stumbling along in hope of identifying a fault ... you'd be good for one of those places, where they swap boards without wasting time on diagnostics ... and 10k watchers, do not deserve it ...
Congrats for the 10k subs, a viewer from Greece!
Thank you!
Wow that receiver was baked.
Beautiful piece.
Congratulations or reaching the 10K milestone 👍
Congrats on 10k!
Thank You!
.Great work
Valuable information.
Thank you.
Gives me something to learn.
Always loved anything mechanical
and engineering.
As long as we learn something, lol
Thanks!
I had the same receiver a few years ago. The light bulbs for the tuner were glitching (bad solder joint on the connector) and the balance pot was scratching, which resulted in no right channel. Apart from that the receiver was fine, no bad caps and needed no adjustments
Congratulations on 10K !
Great repair!
Great video, and diagnostic skills. I love the way you explain things. This receiver has some hours on it, that's for sure. I'm also active in the same field as you, fixing consumer electronics as a profession. My focus is on vintage audio. Mainly upgrading and fixing amps and cd players.
Currently i'm working up the courage to start a full restoration on a pm 665 VXI. I'm a great fan of hk amps of this era, as they have dc coupling, and very few coupling caps. I did a pm655 7years ago, and recenly that cliënt brought the unit back for some small upgrades and repair. I was reminded again how good these units sound after a full and good restoration, and bought a pm665vxi on Marketplace for my personel collection.
Congrats on the 10.000 subs m8, i'm just surprised it's not a 100K subs (yet😂). Ported over from Xray T's channel some years ago. Also i like the calm way you do and explain things. Without drama, and with knowlege. All the best, and cheers from the Netherlands.
Thanks and welcome to the channel. Hopefully you'll find something helpful for you here. Maybe one day I'll find a 665 Vxi for myself, I'd love to listen to that one fersure.
I have a 665VXI too that needs a repair. Powers up but no sound. I’m a novice with regard to making repairs. Any thoughts on where to begin or likely culprit?
@@dennismeehan8189
Check if your switch for seperating pre and main amp is in the right position. Press it on and off for 10 times first with the amp switched off. Then try it.
@@nicodenhaak3961 It was on the correct setting, but I tried your suggestion anyway and it didn’t work. Thanks anyway.
Excellent video! Thanks 🙏
Trevor.............You are a very good teacher/instructor (for a Canadian-just teasing), I always watch every minute. Important to people like myself that have an addiction to 1976-1979 Stereo Equipment and back in my early days of buying fell victim to ill legitimate Stereo repair charging a fortune and doing little to nothing. No 6 ohm setting, have many 6 ohm speakers. Was enjoying that Blonde tune. Those dreaded green TK caps Room temp 77 F What if it is 75 WTH. 96C = 205F That is pretty damn hot, fry an egg on that.
Thanks for your support Robert. It's nice to see regular faces here on the channel
I hope my vids can help you in some way, Cheers
The hk880 vxi is rated at 60 wpc but H/K rates their power output conservatively. 71.58 wpc is great but not many people will run that receiver at full output. The power transformer seems a bit anemic and small for what it is handling but just "adequate". The excessive voltage sag on the power transformer is a bit concerning but I guess it is ok and will hold out, otherwise the engineers and manufacturer, Shin-Shirasuna wouldn't have released that design into production. If you ever come across the hk990 vxi (90 wpc) at a good price, grab it. That receiver really kicks.
Congrats Trevor! I've had a rash of bad leads lately and it drives me nuts. Stupid rabbit holes I've travelled only to find out I was way off. Grrrr. I have two of the Vxi integrateds. 640 and the big dual transformer 665. The 640 is a little sweety with great sound and unfortunately the 665 has a cracked input board which I've been trying to repair but no luck. I'll get back to it some day.
They really are a treat to listen to when they're running right, hope you get them up soon.
Maybe my vids can be some inspiration for you, lol
Congratulations
HK’s of this age are great sound amplifiers but always check the solder joints.
Wetter it’s this series of receivers or the PM6xx and 6xxx series you can always find plenty of bad solder joints. Especially around transistors that get hot.
Oh, and not to mention some series of TK caps, I have the idea that some are even worse then china caps.
This must be a stereo music power amplifier. For the intermediate option between Class AB and Class A amplification modes, selecting the appropriate quiescent current of the final power transistor can make the sound quality better than Class AB and close to Class A while maintaining the appropriate heat generation. The appropriate quiescent current is probably between 30mA and 80mA, so the value marked on this machine is close to this value. Of course, the drive stage current also needs to be coordinated. For non-Class A amplifiers, the voltage amplifier stage, drive stage, and power stage all have a suitable current value. Thank you for sharing this maintenance video. I am an electronic audio enthusiast, not an expert. I am a learning person. I express some personal opinions that may not be mature based on what I know. I don’t understand English, so this is translated into English through translation software. Thank you!
So according to the circuit diagram, the static current of one channel is: 0.04V/0.27Ω=0.148A
The static power of two channels is: 0.148A*80V*2=23.7W
Hello Trevor -- Just Subscribed about a month or so ago -- Been binging on your videos. An Old tube radio guy & have a couple of Nice Pioneer receivers to get running. Trying to find schematics has been hard for me. I never see you tubers complain though. Can You tell me what's Your Go-To source when you need a Schematic. Your Videos Have Been Particularly helpful understanding how solid state works. Thank You in advance.
Hi Lloyd and welcome to the channel. I find most of my schematics at HiFiEngine and VinylEngine dot com.
I also find a few with just a search with make, model and the words "service manual"
@@TrevorsBench Thanks so much for getting back to me. I did ask Aiden from A-H fix-it He mentioned HiFiEngine but stated "But I hear they're not taking new users. I don't know where else to go unfortunately." I know I can get some with Capacitors Kits & some Owners manuals. I will try The others & searches You mentioned also. Definitely a Big Help. Thank You
@@lloydgreen4091 Interesting they would suspend creating new accounts, I didn't know this.
I've been using a search engine like Google to find service manuals with some success
What does the subsonic filter do? Is it a useful item to have on an amp?
It attenuates low frequencies like 20Hz and below. This is useful for the phono input only.
Very low frequencies can come through from the turntable base and can cause feedback or noticeable noises like thumps or booming from the platter as the stylus rides the vinyl groove.
These low frequency noises can come from things like walking across a room or from the turntable picking up bass note vibrations from the table it's sitting on and can sound quite boomy and annoying. A good solid platform for your turntable is best for reducing these noises.
Some turntable manufacturers made the turntable base to have a lot of mass to prevent these noises from being picked up.
Some cheap turntables used a molded plastic base and can actually resonate in the 50Hz to 200Hz range which causes noticeable feedback and noise at the resonate frequency
@@TrevorsBench Thank you for explanation Trevor I never knew what that was for. I learn something new every day from your channel. I have a Technics SL-D2 and it a heavy one so that helps for what you are describing and I also have a Technics SL1200 which is even heavier than the SL-D2
I wonder if Trevor sells the projects he completes to members?
I've been putting lots of thought lately into how I can sell off some of my growing collection and make it easy for both me and people that are interested.
Ebay is out of the question and am looking for better alternatives. I've had some bad experiences shipping items so I want to avoid that if possible but I know I will have to ship regardless.
I'm open to hearing some ideas from you guys on how to make this happen
Fashioning end caps out of polyethylene or polypropylene is the best way to ship. Close cell bubble wrap and peanut should only be used for taking up room where the product might shift or used to buffet impact should density of end caps be too high.
Additionally: I'd run up a trial ballon where commenting at the end of the video, whether for sale, along with your email address. Just my two cents worth... and enjoy your Friday night vids.
Why did the red square cap fail.
Because it did not study enough.
That foil cap has deteriorated capacitance
Is there a way of messaging you privately? I may want to donate a piece of test equipment if you think you would use it. I'm in the US so I'd need to know how to ship without unnecessary charges beyond postage.
TH-cam hates emails and URLs in the comments. You can find my email in my channel page in the ABOUT section. Click on ....more
Thanks
@@TrevorsBench Sorry, not finding it.
@@mdzacharias Yeah. TH-cam now hides that information on my channel page.
If you look at my channel page, where I describe my channel there is a link tagged on the end of the sentence that says .....more
If you click on that it open the ABOUT window with my info
COPT RIGHTED MUSIC !
Not impressed with the build/component quality of that amp. That's a lot of failed components. Maybe it took a surge at some point.
I think the failed TK caps took out the regulated supply. The tiny 1/2w 47 ohm fuse resistor can only take so much current before it pops
CHANGE ALL THE CAPACITORS VIDEO
VIDEO IS TO LONG !!!!!!!!!!!!!!!!!!!!!!!!!111
Heard you like the long cock.
WTF is wrong with you, commenting a lot of nonsense. If you don't like it, skip it, easy. Are you a toddler or what??
Every channel has someone who is reaching out for help without first divulging the kind of information required for assistance.
... it is embarrassing to call yourself an electronics technician ... guessing, the functions of chips, detecting their use without consulting any parts catalogue, just stumbling along in hope of identifying a fault ... you'd be good for one of those places, where they swap boards without wasting time on diagnostics ... and 10k watchers, do not deserve it ...
... like my comment? ... no, you do not fool me ... watch it at your leisure, and you'll see what I see ...