That's a good example of restoration where engineering of the day allowed space for the modification with at least the same, or better quality result, with reliability as well. I have an Akai AM U03 unit, which needs the same work, (it uses the STK 0040 II, and STK 3042), but I'll firstly try and get the original IC's. My supplier has the STK 0050 II, which is just a higher voltage rating than the STK 0040 II. Thanks for the post. It means I can restore it with confidence.
The original sanyo STK modules sounded phenomenal. unfortunately manufacturers never fitted adequate cooling too them and they ultimately burned out after a couple of years, the new STK fakes are not worth bothering with, its much better to replace them and fit a good quality class d circuit or high end toshiba TDA.
Nice fixing! right now, i'm not feeling alone in this world, almost the same tecniques in common sense fixing and improving having in mind the thermal efficiency are my checklist in any repair that i done and will do. very nice video, greetings from colombia.
i love it when people figure out fixes like this. Theres a guy online that has designed replacement STK0050 and 0080's from all new parts you can buy from mouser. he even designed custom PCB's for them. and his prices are very good. only $10 for a pair of boards. i plan on using them to replace the STK0080's in my Fisher CA-800
+bassblaster505 I just built some stk0039 replacements for a technics receiver a couple months ago. Any idea who is making the 0050 and 0080 board designs / plans? I'd much rather build discrete replacements than use Chinese counterfeits!
Yes i know exactly who made the replacement packs. several people have built them themselves. audiokarma.org/forums/index.php?threads/stk-0050-replacement-for-sx-780-and-others.721181/ Page 1,6 and 7 have photos.
Jordan, thought I was messy but your workshop is a tad untidy, and your scope wants you to give it a wash.. I used those modules with a bluetooth receiver and made a nice little bluetooth amp.. cheers T
I have a broken pioneer sx-680 with bad stk and I just came across a Yamaha r-300 and was going to buy that instead but I learned about the stk’s and I changed my mind
I have used the TDA7293 to replace STC modules in a number of amplifiers. They are OK in most with 4 ohms but only with programme inputs. Everything gets very hot with sine wave testing, in fact exactly as it did with the STCs. Most domestic amplifiers are under sinked and many give ratings for 6 ohms...who makes 6 ohm speakers? very few. The TDA7293 also sounds better than the STC and somewhat more reliable. PS Thank goodness you don't play music while making your vids!!
Michael Beeny hi there i have got a sansui a 707 with a bad stk 2250 and want to replace it with a tda module i want to know if the output of the tda could be connected directly to the output slots 4 and 13 of the stk 2250 to be replaced. thx
I'm not sure quite what you have in mind for direct connections. I don't know the Sansui well enough to advise you. As you have seen from this video you do need a little knowledge to be able to locate the connections. It would be quite easy to get yourself in a real mess.
Hi Jordan. I enjoy and learn from all your videos. Happy to hear you have a 1000 Subscribers, Has always I Liked,Shared and added to playlist. All my best. Bobby
Hakko 936 has been discontinued 2010-2011, replaced by 888. :) I'd have an urge to lop those connectors off the amplifier module PCBs, shortening the modules, if they prevent the modules from fitting nicely.
Great video! That was quite complicated fix. If I could fix some amplifiers, it could be just shorted output transistors and emitter resistors or shorted bridge rectifiers. :)
I'd like to replace a STK4121II (18 pins) with a TDA7264A (11 pins) but TDA don't have a by-pass pin and L and R IN (negatives) too. Is it possible? There are modules to buy or to DIY? Thanks!
I’m glad I stumbled across this video as I’m just about to do the same to my R-300. Question, and this is for you Jordan or anyone else. You removed the emitter resistors from the board as your TDA7293 had emitter resistors on it. I’m using a TDA7294 and using a very common board that is used with these. They do not have a built in emitter resistor and I see that most boards for the 7294 don’t. I see that people hook up their speaker direct to the outputs of these boards. So, should I too remove the emitter resistors? I’m guessing they’re not needed???
I would look at the tda7294 datasheet and see if they have an example circuit. If thr example shows emitter resistors, leave them in and wire the output accordingly
@@JordanPier thank you for the suggestion, I did, but the thing is I also looked at the data sheet for the 7293 and in the example circuit for that I didn’t see any emitter resistor for that device either. Which is weird seeing they were on your board. Also weird they call it an emitter resistor considering both devices actually have a mosfet output stage.
Transistors and stuff like that, but right now, we'll stick just to transistors... but how well do they survive outdoors??? I know where there's a few old devices just laying around rotting. I've considered going out and harvesting some parts off of them. Oh yeah, how about power transformers?
Outdoors, bad. The problem primarily is that moisture accumulates on the leads of the transistors and begins to corrode them. The corrosion propagates up into the transistor body, breaking the hermetic seal and damaging the intermals. Moisture can build up in the transformer housing a compromise the enamel on the windings. You can bake one at a low temperature in the oven, like 120-150 degrees Fahrenheit (if your oven allows for a low setting) for an hour or two to get the moisture to burn off.
thanks for this video < i have sansui AU-X111 Integrated Amplifier the stk 4151x not available i can equivalent to Tda7293 and how i can loop the TA7317 Protector ic to make relay on > for last minute for this video i cant see and understand what you test or check thanks >
@@E.M.Center you need to know supply voltages for you unit and make sure they correspond with safe operating voltage range of the module (max of (-+35) You then Google the datasheet for your stk, look at the pinout and wire it up
Hi Jordan, how does one measure if the stk is bad ? I have an akai am a2 with no relay engaging. Almost all the pins read aprox 40 volts on the stk. I know how to determine faulty output pnp npn transistors but how do i measure these stk modules ? Kind regards
Look up the datasheet on your stk, look at the pinout. Usually if the output pins aren't centering at zero and your power supplies are good then the device is bad
Jordan Pier Thank you for the swift reply ! The chip tests out as bad but luckily i have an exact chip laying around :) The akai am a2 rails run quite hot at 40volts pushing the stk unit to its limit. So i asume this will be a returning problem..
That chem wicks better then all the other brands I tried ,pricey but worth it,may I ask what size are you useing.The one I ordered was a little skinny .
Hi Jordan, enjoyed your videos. I am installing two TDA7294 bds. in a Wersi organ power chassis. It has two inputs that went into the old OM961 amp. modules, inverting and non-inverting. Which input should I connect to the TDA7294 circuit bd? I am thinking the non-inverting? And, it has a bootstrap wire, that also went into the OM961. Do I use the bootstrap? Thank you, Jack.
I would use the non inverting input Not sure if you would need the bootstrap. Most boards have it built in and just take a rail voltage through a circuit. If you don't get any sound upon power up but the amp centers then you might need the bootstrap.
Sir good day so my concern is i have a power amplifier Technics and the power IC is STK 2068 II but i have a problem which is i cant buy this kind of power IC so pls i need to replace but how can i order and how...many thanks...
Not that simple. You need a schematic diagram to find out if it's possible to installed another module type. Voltages are crucial. Then you need to discover whether modules would fit on your heatsink. Sometimes there is not enough room...
@@JordanPier Hi sir thank you very much for your opinion or idea well sofar im still finding out this power IC STK 2068 II but if you have an idea pls try to help me many thanks and more power...
@@angelitogalope1930 Dont waste your time I spent 3 months geting my STK from the USA and it only lasted a month. Everything in the market today is fake china shit. Better you open your bad STK and see if you can fix it. Or go this route. Or go with 5200/1940 transistors. (The transistor route will need a lot more space though. )
hi jordan i have an old akai am u02 amp with the stk 3042 which has started clipping the left channel when it heats up , ive used freeze spray which puts the clipping led off until the heat builds but getting a new stk is near impossible.... can i fit these TDA modules
@@JordanPier Hi Jordan, thanks for the reply. I did speak to someone at Electronica who claimed to have an after market one but I wasn't familiar with their reputation. The man spoke with an obvious Chinese accent and I'm sorry but I've been warned SEVERAL times from veteran techs NOT to buy Russian or especially Chinese parts. I'll call Bill however and see what he has to say. Thanks again.
Hi Jordan. This is the best video by far. I just blew my Kenwood STK4172II. I am going to upgrade to this module. Two questions: Can I increase the amp watts from 100 to perhaps 200 or more watts. Can I look for a 12v power source on the amp and add a pc fan just to cool down the amp.
These amplifiers with these power output modules like this don't last very long I had a Technics and everytime I will blow a module they was very expensive I think around $80.00 on the end I threw the Technics away I brought me a Onkyo amplifier it's been like two decades and up to this day it's still working.
Just tell the audiophiles that you removed an integrated circuit and installed “discrete components” and they’ll ‘hear’ a difference and even pay you more ;)
Подскажите, распиновка какая. Объединил 0 и минусы входов и выходов, питание + 15 на оба модуля , минус с 6 тоже на оба модуля. 1 пин вход L , 15 пин вход R. При включении лампочка ярко горит, но стоит откинуть провода питания + и -. С одного из модулей они работают раздель каждый. В чем беда?
Bora Yurtoren really? lol. i do like this - i put wick on rosin flux, put soldering iron on the wick to heat it up a bit , so the flux melts and soaks into the wick. then the wick sucks up solder very good.
Bad assembly work. It would have been enough to remove two fins from the heatsink to put the modules side by side horizontally and solve all the problems. Pessimo lavoro di assemblaggio. Sarebbe bastato eliminare due alette dal dissipatore per mettere i moduli affiancati in orizzontale e risolvere tutti i problemi.
That's a good example of restoration where engineering of the day allowed space for the modification with at least the same, or better quality result, with reliability as well. I have an Akai AM U03 unit, which needs the same work, (it uses the STK 0040 II, and STK 3042), but I'll firstly try and get the original IC's. My supplier has the STK 0050 II, which is just a higher voltage rating than the STK 0040 II.
Thanks for the post. It means I can restore it with confidence.
The original sanyo STK modules sounded phenomenal. unfortunately manufacturers never fitted adequate cooling too them and they ultimately burned out after a couple of years, the new STK fakes are not worth bothering with, its much better to replace them and fit a good quality class d circuit or high end toshiba TDA.
Amazing that you can leave all those holes where the STK has been and it all still works
Nice fixing! right now, i'm not feeling alone in this world, almost the same tecniques in common sense fixing and improving having in mind the thermal efficiency are my checklist in any repair that i done and will do.
very nice video, greetings from colombia.
i love it when people figure out fixes like this. Theres a guy online that has designed replacement STK0050 and 0080's from all new parts you can buy from mouser. he even designed custom PCB's for them. and his prices are very good. only $10 for a pair of boards. i plan on using them to replace the STK0080's in my Fisher CA-800
+bassblaster505 I just built some stk0039 replacements for a technics receiver a couple months ago.
Any idea who is making the 0050 and 0080 board designs / plans? I'd much rather build discrete replacements than use Chinese counterfeits!
Yes i know exactly who made the replacement packs. several people have built them themselves.
audiokarma.org/forums/index.php?threads/stk-0050-replacement-for-sx-780-and-others.721181/
Page 1,6 and 7 have photos.
bassblaster505 thanks! I'll have a look.
Fantastic! Ive thought about doing this myself but hadnt seen it done. Im a huge fan of these chip amp boards
Thank you very much. I suspected something like this would work on the STK powered Amplifier/Receiver units.
Awesome!
I have a small guitar amp that uses an SDK that burned off the numbers.
This gives me ideas to resurrect it.
The first video of yours that i've watched,
Came here from a shango066 recommendation,
wasn't disappointed excellent content.
Jordan, thought I was messy but your workshop is a tad untidy, and your scope wants you to give it a wash.. I used those modules with a bluetooth receiver and made a nice little bluetooth amp.. cheers T
I have a broken pioneer sx-680 with bad stk and I just came across a Yamaha r-300 and was going to buy that instead but I learned about the stk’s and I changed my mind
I would recommend soldering straight to the modules. I've has some bad luck with those cheap terminal blocks.
Same here. I prefer direct connections.
chemwick is number one, works where others lift pads... and kester 44 solder in 63/37
alpha solder mil spec is great also..
I have used the TDA7293 to replace STC modules in a number of amplifiers. They are OK in most with 4 ohms but only with programme inputs. Everything gets very hot with sine wave testing, in fact exactly as it did with the STCs. Most domestic amplifiers are under sinked and many give ratings for 6 ohms...who makes 6 ohm speakers? very few. The TDA7293 also sounds better than the STC and somewhat more reliable. PS Thank goodness you don't play music while making your vids!!
Michael Beeny hi there i have got a sansui a 707 with a bad stk 2250 and want to replace it with a tda module i want to know if the output of the tda could be connected directly to the output slots 4 and 13 of the stk 2250 to be replaced. thx
I'm not sure quite what you have in mind for direct connections. I don't know the Sansui well enough to advise you. As you have seen from this video you do need a little knowledge to be able to locate the connections. It would be quite easy to get yourself in a real mess.
Great explanation, helped me with the info about ground loop
Hi Jordan. I enjoy and learn from all your videos. Happy to hear you have a 1000 Subscribers, Has always I Liked,Shared and added to playlist.
All my best.
Bobby
Hello Jordan. I learned something new. ground loops.
Thank you for your sharing your experience.
Hakko 936 has been discontinued 2010-2011, replaced by 888. :)
I'd have an urge to lop those connectors off the amplifier module PCBs, shortening the modules, if they prevent the modules from fitting nicely.
Totally enjoyed your videos. Very informative!
Hi Can you please tell me the equivalent transistors of B1254 (2SA1263), D1894 (2SC3180). its really hard to find to me..
Great video! That was quite complicated fix. If I could fix some amplifiers, it could be just shorted output transistors and emitter resistors or shorted bridge rectifiers. :)
I wonder if those could replace convergence Ic stk's in a Toshiba projection tv.
I'd like to replace a STK4121II (18 pins) with a TDA7264A (11 pins) but TDA don't have a by-pass pin and L and R IN (negatives) too. Is it possible? There are modules to buy or to DIY?
Thanks!
Thanks Jordan,,, that was really good. btw,,,,, congrats on the grand.
I’m glad I stumbled across this video as I’m just about to do the same to my R-300. Question, and this is for you Jordan or anyone else. You removed the emitter resistors from the board as your TDA7293 had emitter resistors on it. I’m using a TDA7294 and using a very common board that is used with these. They do not have a built in emitter resistor and I see that most boards for the 7294 don’t. I see that people hook up their speaker direct to the outputs of these boards. So, should I too remove the emitter resistors? I’m guessing they’re not needed???
I would look at the tda7294 datasheet and see if they have an example circuit. If thr example shows emitter resistors, leave them in and wire the output accordingly
@@JordanPier thank you for the suggestion, I did, but the thing is I also looked at the data sheet for the 7293 and in the example circuit for that I didn’t see any emitter resistor for that device either. Which is weird seeing they were on your board. Also weird they call it an emitter resistor considering both devices actually have a mosfet output stage.
Does anyone know the p/n of this yuan-jing module. I can't find one like this, only far more complex ones which I definitely don't need.
Can u do a video on how to test the actual stk module to check and see if its faulty or not
Transistors and stuff like that, but right now, we'll stick just to transistors... but how well do they survive outdoors??? I know where there's a few old devices just laying around rotting. I've considered going out and harvesting some parts off of them. Oh yeah, how about power transformers?
Outdoors, bad.
The problem primarily is that moisture accumulates on the leads of the transistors and begins to corrode them. The corrosion propagates up into the transistor body, breaking the hermetic seal and damaging the intermals.
Moisture can build up in the transformer housing a compromise the enamel on the windings. You can bake one at a low temperature in the oven, like 120-150 degrees Fahrenheit (if your oven allows for a low setting) for an hour or two to get the moisture to burn off.
Listening to this video with my homemade stk442-090 amplifier, but I had luck to get original IC from 90s :)
thanks for this video < i have sansui AU-X111 Integrated Amplifier
the stk 4151x not available i can equivalent to Tda7293 and how i can loop the TA7317 Protector ic to make relay on > for last minute for this video i cant see and understand what you test or check
thanks >
Check the service manual for operating voltages and make sure it's no more than +-35vdc.
NEVER BYPASS THE PROTECTION CIRCUIT.
@@JordanPier
thanks for your cooperation the stk 4151 x not available i can replacement to stk4151II > i think same pin assessment . thanks
@@E.M.Center you need to know supply voltages for you unit and make sure they correspond with safe operating voltage range of the module (max of (-+35)
You then Google the datasheet for your stk, look at the pinout and wire it up
please help! Can I replace power amplifer stk032 with another power amplifer? Thank you very much!
@Jordan Pier great job!!!!
Hi Jordan, how does one measure if the stk is bad ? I have an akai am a2 with no relay engaging. Almost all the pins read aprox 40 volts on the stk. I know how to determine faulty output pnp npn transistors but how do i measure these stk modules ? Kind regards
Look up the datasheet on your stk, look at the pinout. Usually if the output pins aren't centering at zero and your power supplies are good then the device is bad
Jordan Pier Thank you for the swift reply ! The chip tests out as bad but luckily i have an exact chip laying around :) The akai am a2 rails run quite hot at 40volts pushing the stk unit to its limit. So i asume this will be a returning problem..
That chem wicks better then all the other brands I tried ,pricey but worth it,may I ask what size are you useing.The one I ordered was a little skinny .
Hi Jordan, enjoyed your videos. I am installing two TDA7294 bds. in a Wersi organ power chassis. It has two inputs that went into the old OM961 amp. modules, inverting and non-inverting. Which input should I connect to the TDA7294 circuit bd? I am thinking the non-inverting? And, it has a bootstrap wire, that also went into the OM961. Do I use the bootstrap? Thank you, Jack.
I would use the non inverting input
Not sure if you would need the bootstrap. Most boards have it built in and just take a rail voltage through a circuit.
If you don't get any sound upon power up but the amp centers then you might need the bootstrap.
@@JordanPier Hi, If I do need the bootstrap, should I solder directly to pin 6 at the TDA? Thank you, Jack
@@jackcallahan2799 I'd look at the tda7294 datasheet. They have the bootstrap decoupled to the output at pin14 through a 22uf capacitor.
@@JordanPier Thank you I will take a look. If it is decoupled, I should connect bootstrap. Do i understand you correctly?
@@jackcallahan2799 give it a shot as long as it's decoupled. I forget if it's a clamp function to prevent transients during startup or what....
Sir good day so my concern is i have a power amplifier Technics and the power IC is STK 2068 II but i have a problem which is i cant buy this kind of power IC so pls i need to replace but how can i order and how...many thanks...
Not that simple.
You need a schematic diagram to find out if it's possible to installed another module type. Voltages are crucial. Then you need to discover whether modules would fit on your heatsink. Sometimes there is not enough room...
@@JordanPier Hi sir thank you very much for your opinion or idea well sofar im still finding out this power IC STK 2068 II but if you have an idea pls try to help me many thanks and more power...
@@angelitogalope1930 Dont waste your time I spent 3 months geting my STK from the USA and it only lasted a month. Everything in the market today is fake china shit. Better you open your bad STK and see if you can fix it. Or go this route. Or go with 5200/1940 transistors. (The transistor route will need a lot more space though. )
@@ronchinoy but sound way better
You are numero 1.
What you should was just remove to two inner fins and mount them Horizontal on the heat sink. Great video though, nice work.
I would do exactly the same, except if I was working at night and it was not a big idea to turn on angle grinder at that time ....
hi jordan
i have an old akai am u02 amp with the stk 3042 which has started clipping the left channel when it heats up , ive used freeze spray which puts the clipping led off until the heat builds but getting a new stk is near impossible.... can i fit these TDA modules
Check power supplies per the schematics. Save limits for these are +-35v. You may have to chase ground loops like I did.
@@JordanPier thanks jordan
@@JordanPier found it !! dry joint on one of the darlingtons . leaving it on all night on a soak test . fingers crossed
@@mactheweld awesome. Heres hoping it holds up!
add paste flux to ordinary wick for the same performance . i use oaty plumbers paste flux . i also REMOVE it ...
manufacturers did not care to remove flux and shit worked for 30years but every single one on youtube comments cries if flux is left on a repair
are those mono or stereo modules?
Mono
There’s room for a fan on the back of the heatsink
tda rocks...but dear? why don't you think about replacing with tda8950 class d amplifier???
Sunt integrate foarte bune,👍👍👍⭐⭐⭐
Alguien me podría decir donde puedo encontrar esos TDA de biena calidad aquí en México, ya que los consigo por 6.5 dolares pero son Chinos.
"Mouser Electronics" Se enviará a México. Debería poder comprarles el TDA7293, pero tampoco estoy seguro acerca de la placa.
Can anyone recommend where to buy a STK 3076? thanks
Call Electronica in Colorado. Talk to Bill. 303 322 3037
He may have a legit one. Won't be cheap.
@@JordanPier Hi Jordan, thanks for the reply. I did speak to someone at Electronica who claimed to have an after market one but I wasn't familiar with their reputation. The man spoke with an obvious Chinese accent and I'm sorry but I've been warned SEVERAL times from veteran techs NOT to buy Russian or especially Chinese parts. I'll call Bill however and see what he has to say. Thanks again.
Hi Jordan. This is the best video by far. I just blew my Kenwood STK4172II. I am going to upgrade to this module. Two questions: Can I increase the amp watts from 100 to perhaps 200 or more watts.
Can I look for a 12v power source on the amp and add a pc fan just to cool down the amp.
Power is dependent on supply voltage. If looking for 12vmake sure amp draw from fan doesn't overtax power supply
Does the tone control still work?
Yes.
Great video. I'm gonna do this on a Sankyo SRC-2020. Do I no longer use the feedback and bias wires? Thanks
Jumped out of pre-amp into small amp and everything checks out good. Your fix would be great on this.
Matt, essentially that's all you'd do. Take the preamp out and feed it to the module
Ok, thanks
These amplifiers with these power output modules like this don't last very long I had a Technics and everytime I will blow a module they was very expensive I think around $80.00 on the end I threw the Technics away I brought me a Onkyo amplifier it's been like two decades and up to this day it's still working.
What does it sound like?
I didn't really notice any difference from the original stks
Just tell the audiophiles that you removed an integrated circuit and installed “discrete components” and they’ll ‘hear’ a difference and even pay you more ;)
Perfect i didn't know that this is possible !? 😕😯
уф. я уже подумал здесь будут шоколадку анатомировать. но... все банально просто.
Подскажите, распиновка какая. Объединил 0 и минусы входов и выходов, питание + 15 на оба модуля , минус с 6 тоже на оба модуля. 1 пин вход L , 15 пин вход R. При включении лампочка ярко горит, но стоит откинуть провода питания + и -. С одного из модулей они работают раздель каждый. В чем беда?
Pinout please
Very good
Sanyo Electric, which manufactured the "STK Power Pack", has gone bankrupt.
Sanyo Electric is a Japanese company.
Πως καθαρίζουν. Τα κυκλώματα ενός σ
So that is how a solder wick is supposed to work... I could not believe my eyes, I am throwing out all the wick that I have at the moment..
Bora Yurtoren really? lol. i do like this - i put wick on rosin flux, put soldering iron on the wick to heat it up a bit , so the flux melts and soaks into the wick. then the wick sucks up solder very good.
Super sar
Bad assembly work. It would have been enough to remove two fins from the heatsink to put the modules side by side horizontally and solve all the problems. Pessimo lavoro di assemblaggio. Sarebbe bastato eliminare due alette dal dissipatore per mettere i moduli affiancati in orizzontale e risolvere tutti i problemi.
a test music !!!
That 'scope is disgusting. Shame on you!
Fake STK... , just open it, heard that even TDA7293 can be found fake these days , for a value around 3 USD ....sad
Yo compré uno de 6.5 dólares, consideras que pudiera ser falso? Bueno en realidad es chino
28:40 a bird?