Just found Chris tonight , literally had my mind blown in this video. I'm wondering if some other vintage stereo repair guys go the extra mile like this and actually test the equipment as well as he does? To say you do it , and actually doing it.......two different things.
Doubtful, in my area, it can take many months, or a year or longer to get a piece of gear into a shop. They are doing the bare minimum, I have friends, and they charge top dollar.
Thank you for the video Chris... I just pulled the trigger on a Siglent SDM3045X DMM... I also have a Rigol o-scope coming along with a UNI-T UTG962E Arbitrary Waveform Generator, and a bunch of other stuff. 33 years as a truck driver, shade tree mechanic, home owner, electrical, plumbing, etc... Tools up the wazoo. I discovered the vintage audio a year ago, two Sansui units, a 4000 and a 2000, they will be my first projects. I want to learn these repairs, as the stress of trucking and years in the oil fields have taken their toll on my body. Here in my area, shops are backed up for months, and it is not uncommon to have a year or longer wait. I know a few local guys that are doing these repairs out of their homes, and are backlogged for months themselves. I see a market here, just need to hit the books and really learn this stuff. Not afraid to dig in to a piece of gear, just need the practice and time. Simple stuff, crawl before I walk and then run. Thanks again for the videos Chris!
Hello, I hope you are well, I follow your channel very carefully, they are a great help for those of us who are not technical, they are a great help, I am very pleased to share your great knowledge, detail and patience with us.
@@mikeschlup5279 I sprayed all the pots with cleaner about a year ago. The volume pot started getting scratchy. I did a visual inspection of the caps, looked for leakage, corrosion, signs of over-heating. Vacuumed everything out.. All looks fine but one doesn't really know until you get it on a scope. I know a local repair dude; serviced my Trace Elliot Twin Valve bass head. 🙂
Beginner question. I've worked on a Marantz 1040 and it seems to work perfectly, all knobs and buttons are clean now and it outputs 24.9W/channel, bias set to 20mv and the other setting to 0v as per manual. The only thing I don't understand is when the input knob is on anything else but the source, you can hear the source leaking in mono through the speakers. Turning the volume to the middle lowers that sound. Is this normal behaviour ? Thanks for your video's.
Wow! Intense stuff! My son has a Luxman L-3 that blew his speaker and I measured 40 volts DC on the left speaker terminal. I'm trying to get him to toss it because he has so many amps but he thinks he can sell it to somebody that can fix it. I just want it out of my garage. LOL
Man, I'd love to purchase it from you if you can send it to Florida and your son is willing to let it go. Shoot me an email at mrbrain1733@gmail if your interested.
I am working on a "readers digest" brand 8-track am/fm stereo. When they soldered the parts to the board, they folded the leads over on to the traces- then soldered. UGH! Nightmare! Is this typical of 70's type hi-fi?
This is very cool.. Great info and well explained. Chris ..can I set up my scope for this (is it software for digital scope ? ) or is this some software for a bench DMM ?
Thank You. I have a Siglent 3045X DMM that I connect via it's USB connection to my Win 10 computer. I use Siglents Software utility called EasyDMM to capture what the DMM is reading to the computer. I then use a program called Flashback Express which allows you to capture and save the video data on your monitor to your computer. I then use Divinci Resolve to edit the video that you see on UA-cam.
@@vintageaudioaddict Thank you ! I may now get a bench dmm. Been thinking about it, if not for the form factor this is yet another use. Great content on your channel Chris ! I'm restoring an sx-737. It's been fun until I got to the lamps :- ) All ok now though !
Chris, Excellent info as always! Sir, I would like to ask about how you captured the voltage changes. I've wanted a strip recorder for many of the same reasons for a very long time. Bummer I can't afford a recording scope yet. Many thanks and please have a great day.
Thank you. I have a Siglent 3045X DMM that I connect via it's USB connection to my Win 10 computer. I use Siglents Software utility called EasyDMM to capture what the DMM is reading to the computer. I then use a program called Flashback Express which allows you to capture and save the video data on your monitor to your computer. After that I use Divinci Resolve to edit the video that you see on UA-cam.
@@vintageaudioaddict Awesome Chris! Thanks a million. Keep up your great work. I plan to use your advice to help me correct a NAD 214 amp that is running much warmer than my cool running 214 that even sounds a bit better. All the very best, Kevin
Not normally when playing music but these spikes affect the overall quality of sound that you hear. With a steady tone or just sitting at idle with the volume turned up some, maybe?
I’m starting to wonder if my Pioneer receiver hasn’t started to do this. I thought it was just transients coming from the Bluetooth receiver because that’s all I ever run through it these days. What failing components are usually behind these spikes and offsets?
Lots of different failures can pop up in the older audio gear that are caused by a variety of reasons including defective transistors and capacitors. To start, I would check in the service manual for your receiver and see if it contains C1451 transistors. If it does that would be something to check out.
@@vintageaudioaddict Thanks. Looks like no C1451s in the Pioneer SX-880 but I will haul the thing down to the bench for some investigation one of these days.
Very interesting. I am not a tech, so over my head. I recently bought a Luxman L100 and a L580 and both had (R) channel issues in the preamp section? Distorts then fades then goes silent. Do all techs check what you are showing us?
Thanks for watching. A lot of techs don't because time is money. Many times folks who bring in equipment for repair don't want to pay anything extra. They just want the problem that it was brought in for taken care of.
There are a ton of tantalum caps and 2SC870 transistors, (IIRC), in the L100. I think I replaced 52 transistors alone on one plus all of the caps. Not easy, but WELL worth it. Outstanding unit!
Part of the issue was caused by "Change On Sight" Transistors in the pre/power amp that have been known trouble makers for many years. The other issue was a regulated power supply problem that was also caused by a defective transistor. This issue was unrelated to the transistor issue in the Pre/Power Amp section.
Had these on one amp as well.... In my case it was the filter caps, having internal connection problems... I removed them and tested them separate....some times it was good for minutes and then randomly draw some several 100mA dropped its voltage and came back good for minutes...never seen that before..and the other one was ok doing the same tests.... I left the faulty one on my lab-power supply for several hours under voltage and current control... Sometimes it even produces surges up to 500mA.... Strange... Now let see what the problem here... 😉 😊
It almost looks like an ECM spike. like the ones satellite providers sent out to burn pirated equipment. A spike like that can easilly be produce digitally, can it? Like in a cd for instance.
Thanks. I know I didn't get into details about the cause. I plan to do a complete video on this SA-9900 in the future that will include in detail what caused it. My goal in this video was to try and explain that this issue can be in any of the older audio gear. It doesn't matter the brand or model. All of the manufactures used the technology of the day, in this case the 1970's. Using similar design techniques as well as using the parts available most of the brands/models are more similar than different. Now to answer you question. Part of the issue was caused by "Change On Sight" Transistors in the pre/power amp that have been known trouble makers for many years in vintage audio equipment. The other issue was a regulated power supply problem that was also caused by a defective transistor. This issue was unrelated to the transistor issues in the Pre/Power Amp section.
Hmm, interesting, I didn't know that this issue could even happen... Is this exclusive to vintage Pioneer amps, or is this a common problem among pretty much ALL vintage amplifiers?... And the real question here is what exactly causes it, AND how do you go about fixing this issue?!
I know I didn't get into many details about the cause. I plan to do a complete video on this SA-9900 in the future that will include in detail what caused it. My goal in this video was to try and explain that this issue can be in any of the older audio gear. It doesn't matter the brand or model. All of the manufactures used the technology of the day, in this case the 1970's. Using similar design techniques as well as using the parts available most of the brands/models are more similar than different. Now to answer you question. Part of the issue was caused by "Change On Sight" Transistors in the pre/power amp that have been known trouble makers for many years. The other issue was a regulated power supply problem that was also caused by a defective transistor. This issue was unrelated to the transistor issue in the Pre/Power Amp section.
Love all of your videos I’ve seen so far. Very informative. Coincidentally I just got a JVC ja s77, my second and it was working then I checked and adjusted the basic alignments. This unit has 3 that you can do with a multimeter. main amp center, main amp idling, and equalizer amp center. Well, the right channel of the idling current supposed to be 4.4 mvolts and it was around 50 mV so I adjusted down but wouldn’t come below 23 mV. This caused the right channel not to work at all. Adjusted back up further away from nominal and it would work again, but that channel was heating up more than the left. Anyways had to send it back. Might of been that potentiometer because it was erratic but because it wouldn’t come down enough probably more wrong than just the pot? Wasn’t going to pay full price for something broke.
Thanks for sharing. Vintage units like your JVC were built to last but after all of these years there are going to be issues with them. Most of the problems can be solved and they can operate for many more decades.
Some "change on sight" transistors in the pre and power amp section along with a power supply issue that was also a transistor issue. Thanks for watching.
Well, multiple problems that moved me in various directions. I plan to do a video on the repair but it was a combination of the known "change on sight" transistors in this unit along with a power supply issue. I did replace the original filter capacitors.
I did change out the old electrolytic capacitors but the issue was caused by "Change On Sight" Transistors in the pre/power amp that have been known trouble makers for many years in vintage audio equipment. The other issue was a regulated power supply problem that was also caused by a defective transistor. This issue was unrelated to the transistor issue in the Pre/Power Amp section.
Just found Chris tonight , literally had my mind blown in this video. I'm wondering if some other vintage stereo repair guys go the extra mile like this and actually test the equipment as well as he does? To say you do it , and actually doing it.......two different things.
Doubtful, in my area, it can take many months, or a year or longer to get a piece of gear into a shop. They are doing the bare minimum, I have friends, and they charge top dollar.
Thank you for the video Chris... I just pulled the trigger on a Siglent SDM3045X DMM... I also have a Rigol o-scope coming along with a UNI-T UTG962E Arbitrary Waveform Generator, and a bunch of other stuff. 33 years as a truck driver, shade tree mechanic, home owner, electrical, plumbing, etc... Tools up the wazoo. I discovered the vintage audio a year ago, two Sansui units, a 4000 and a 2000, they will be my first projects. I want to learn these repairs, as the stress of trucking and years in the oil fields have taken their toll on my body.
Here in my area, shops are backed up for months, and it is not uncommon to have a year or longer wait. I know a few local guys that are doing these repairs out of their homes, and are backlogged for months themselves. I see a market here, just need to hit the books and really learn this stuff. Not afraid to dig in to a piece of gear, just need the practice and time. Simple stuff, crawl before I walk and then run. Thanks again for the videos Chris!
Hello, I hope you are well, I follow your channel very carefully, they are a great help for those of us who are not technical, they are a great help, I am very pleased to share your great knowledge, detail and patience with us.
Excellent video!
Thanks for your expert analysis Chris, I learn something every time I tune in to your channel...
Kirk, thank you so much for your kind words and for watching.
Thanks for the tip! I've had my NAD 3155 since the mid 80's and it doesn't seem to 'punch' as dynamically as I remember .. It's due for a tune-up!
Your welcome. Thanks for watching.
I have one too...deoxit all the switches.. don't know where to start after that...
@@mikeschlup5279 I sprayed all the pots with cleaner about a year ago. The volume pot started getting scratchy. I did a visual inspection of the caps, looked for leakage, corrosion, signs of over-heating. Vacuumed everything out.. All looks fine but one doesn't really know until you get it on a scope. I know a local repair dude; serviced my Trace Elliot Twin Valve bass head. 🙂
@@DoghouseFunkBlaster65 I would send it anywhere. At some point. Just had to spend 3400. to pass e check..would have bought a nice Yamaha I.A.
Thank you for your time with this video; I always learn watching your video's.
Glad you like them!
Excellent video as usual, Chris!
Thanks Don
Beginner question. I've worked on a Marantz 1040 and it seems to work perfectly, all knobs and buttons are clean now and it outputs 24.9W/channel, bias set to 20mv and the other setting to 0v as per manual.
The only thing I don't understand is when the input knob is on anything else but the source, you can hear the source leaking in mono through the speakers. Turning the volume to the middle lowers that sound. Is this normal behaviour ? Thanks for your video's.
Wow! Intense stuff! My son has a Luxman L-3 that blew his speaker and I measured 40 volts DC on the left speaker terminal. I'm trying to get him to toss it because he has so many amps but he thinks he can sell it to somebody that can fix it. I just want it out of my garage. LOL
Man, I'd love to purchase it from you if you can send it to Florida and your son is willing to let it go. Shoot me an email at mrbrain1733@gmail if your interested.
My brother's Luxman L2 fried 2 speakers due to the DC at the output. The output transistors shorted and a couple of 220 ohms resistors burnt.
The dreaded DC offset..... This and bad filter caps are the most common issues I see....
I am working on a "readers digest" brand 8-track am/fm stereo. When they soldered the parts to the board, they folded the leads over on to the traces- then soldered. UGH! Nightmare! Is this typical of 70's type hi-fi?
Yes that sounds right.
Can you tell this neophyte what you are looking at and how you set it up.
This is very cool.. Great info and well explained. Chris ..can I set up my scope for this (is it software for digital scope ? ) or is this some software for a bench DMM ?
Thank You. I have a Siglent 3045X DMM that I connect via it's USB connection to my Win 10 computer. I use Siglents Software utility called EasyDMM to capture what the DMM is reading to the computer. I then use a program called Flashback Express which allows you to capture and save the video data on your monitor to your computer. I then use Divinci Resolve to edit the video that you see on UA-cam.
@@vintageaudioaddict Thank you ! I may now get a bench dmm. Been thinking about it, if not for the form factor this is yet another use. Great content on your channel Chris ! I'm restoring an sx-737. It's been fun until I got to the lamps :- ) All ok now though !
Chris, Excellent info as always! Sir, I would like to ask about how you captured the voltage changes. I've wanted a strip recorder for many of the same reasons for a very long time. Bummer I can't afford a recording scope yet. Many thanks and please have a great day.
Thank you. I have a Siglent 3045X DMM that I connect via it's USB connection to my Win 10 computer. I use Siglents Software utility called EasyDMM to capture what the DMM is reading to the computer. I then use a program called Flashback Express which allows you to capture and save the video data on your monitor to your computer. After that I use Divinci Resolve to edit the video that you see on UA-cam.
@@vintageaudioaddict Awesome Chris! Thanks a million. Keep up your great work. I plan to use your advice to help me correct a NAD 214 amp that is running much warmer than my cool running 214 that even sounds a bit better. All the very best, Kevin
Hello! Can those things be audible or by playing a sine tone for a couple of minutes and monitoring the volume level?
Not normally when playing music but these spikes affect the overall quality of sound that you hear. With a steady tone or just sitting at idle with the volume turned up some, maybe?
I’m starting to wonder if my Pioneer receiver hasn’t started to do this. I thought it was just transients coming from the Bluetooth receiver because that’s all I ever run through it these days. What failing components are usually behind these spikes and offsets?
Lots of different failures can pop up in the older audio gear that are caused by a variety of reasons including defective transistors and capacitors. To start, I would check in the service manual for your receiver and see if it contains C1451 transistors. If it does that would be something to check out.
@@vintageaudioaddict Thanks. Looks like no C1451s in the Pioneer SX-880 but I will haul the thing down to the bench for some investigation one of these days.
Very interesting. I am not a tech, so over my head. I recently bought a Luxman L100 and a L580 and both had (R) channel issues in the preamp section? Distorts then fades then goes silent. Do all techs check what you are showing us?
Thanks for watching. A lot of techs don't because time is money. Many times folks who bring in equipment for repair don't want to pay anything extra. They just want the problem that it was brought in for taken care of.
There are a ton of tantalum caps and 2SC870 transistors, (IIRC), in the L100. I think I replaced 52 transistors alone on one plus all of the caps. Not easy, but WELL worth it. Outstanding unit!
And what would be the cause for these spikes?
Part of the issue was caused by "Change On Sight" Transistors in the pre/power amp that have been known trouble makers for many years. The other issue was a regulated power supply problem that was also caused by a defective transistor. This issue was unrelated to the transistor issue in the Pre/Power Amp section.
How can I find a good shop to service my vintage amp and pre amp? I really have no idea where to begin to look.
Try to Google "Vintage Audio Repair" See if anyone comes up in your area.
Had these on one amp as well.... In my case it was the filter caps, having internal connection problems... I removed them and tested them separate....some times it was good for minutes and then randomly draw some several 100mA dropped its voltage and came back good for minutes...never seen that before..and the other one was ok doing the same tests.... I left the faulty one on my lab-power supply for several hours under voltage and current control... Sometimes it even produces surges up to 500mA.... Strange... Now let see what the problem here... 😉 😊
It almost looks like an ECM spike. like the ones satellite providers sent out to burn pirated equipment. A spike like that can easilly be produce digitally, can it? Like in a cd for instance.
Wow vintage gear looked so imposing and classy
This is a cliff hanger…… my knowledge tells me it aint filter capacitors, rather in signal path….. waiting for analysis 😅
I would suspect leaky capacitors.
Ended up being transistor related but I did replace all of the old electrolytic capacitors. It was time.
great video chris but , you never told us what you did to resolve the issue.
Thanks. I know I didn't get into details about the cause. I plan to do a complete video on this SA-9900 in the future that will include in detail what caused it. My goal in this video was to try and explain that this issue can be in any of the older audio gear. It doesn't matter the brand or model. All of the manufactures used the technology of the day, in this case the 1970's. Using similar design techniques as well as using the parts available most of the brands/models are more similar than different. Now to answer you question. Part of the issue was caused by "Change On Sight" Transistors in the pre/power amp that have been known trouble makers for many years in vintage audio equipment. The other issue was a regulated power supply problem that was also caused by a defective transistor. This issue was unrelated to the transistor issues in the Pre/Power Amp section.
@@vintageaudioaddict much respect. thank you chris
Hmm, interesting, I didn't know that this issue could even happen... Is this exclusive to vintage Pioneer amps, or is this a common problem among pretty much ALL vintage amplifiers?... And the real question here is what exactly causes it, AND how do you go about fixing this issue?!
I know I didn't get into many details about the cause. I plan to do a complete video on this SA-9900 in the future that will include in detail what caused it. My goal in this video was to try and explain that this issue can be in any of the older audio gear. It doesn't matter the brand or model. All of the manufactures used the technology of the day, in this case the 1970's. Using similar design techniques as well as using the parts available most of the brands/models are more similar than different. Now to answer you question. Part of the issue was caused by "Change On Sight" Transistors in the pre/power amp that have been known trouble makers for many years. The other issue was a regulated power supply problem that was also caused by a defective transistor. This issue was unrelated to the transistor issue in the Pre/Power Amp section.
How would people not hear a 100mV spike going to the speakers?
I can't answer your question but thousands of folks around the world are listening to their vintage gear with this issue.
thumbs up!
Thanks for the visit
Love all of your videos I’ve seen so far. Very informative. Coincidentally I just got a JVC ja s77, my second and it was working then I checked and adjusted the basic alignments. This unit has 3 that you can do with a multimeter. main amp center, main amp idling, and equalizer amp center. Well, the right channel of the idling current supposed to be 4.4 mvolts and it was around 50 mV so I adjusted down but wouldn’t come below 23 mV. This caused the right channel not to work at all. Adjusted back up further away from nominal and it would work again, but that channel was heating up more than the left. Anyways had to send it back. Might of been that potentiometer because it was erratic but because it wouldn’t come down enough probably more wrong than just the pot? Wasn’t going to pay full price for something broke.
Thanks for sharing. Vintage units like your JVC were built to last but after all of these years there are going to be issues with them. Most of the problems can be solved and they can operate for many more decades.
I would say noisy transistors. Pioneers have a history of them.
Yup, that was part of the problem. Had a power supply issue that was the other part. I'm going to do a full video on the SA-9900 in the future.
Not Yamahas
Electrolytic caps no doubt.
Some "change on sight" transistors in the pre and power amp section along with a power supply issue that was also a transistor issue. Thanks for watching.
Let me guess filter capacitor failure.
Well, multiple problems that moved me in various directions. I plan to do a video on the repair but it was a combination of the known "change on sight" transistors in this unit along with a power supply issue. I did replace the original filter capacitors.
Leaky transistors.
Yup, you are correct.
Corrosion or oxide that bulitd up on legs of element, enters the enclosure of elemejt and corrupt the semoconductor inside.
negative feed back and bad caps
I did change out the old electrolytic capacitors but the issue was caused by "Change On Sight" Transistors in the pre/power amp that have been known trouble makers for many years in vintage audio equipment. The other issue was a regulated power supply problem that was also caused by a defective transistor. This issue was unrelated to the transistor issue in the Pre/Power Amp section.