Hey there, Tony. Thanks so much for showing that PACE Lead Bender tool. I ordered one, and it makes fitting parts onto a PCB or even P to P wiring so much easier. Thanks again. I work in a shop repairing mostly guitars but also tube amps. Love your vids, because they’ve helped me with somewhat of a blind spot I had with repairing solid state gear as well. Just means more customers. 👍🔊😊🎶
I like your banter Tony!! The extra bits were nice to see...but "our conversations" are almost what I get most out of your videos! ..I won't stop watching ;-) I REALLY appreciate the time & effort you put into your vids!!! THANKS!!!!
@ 13:00 That output transistor configuration is more like a "Cascode" configuration, used by Nelson Pass in his Threshold 800A amp dating back to it's production in early 1975. If you notice, the transistors closest to the power rails are biased by their own resistor divider network, which is separate from the inner transistors variable bias , and the transistors being in series with the outer transistors being biased on already, helps compensate for the miller capacitance of the series connected transistors, giving them a higher fT / transistion frequency, then they would normally have (w2aew has a good video on this) The outer transistors AF base signal is then driven by the common output rail of the inner transistors closest to it.
I have a feeling that Tony had a person make a comment like I was presented with awhile back, that stated that I talk to much, so, we get the silent treatment. 🤣 All I know, in in the things he shares with us while chatting, he often drops valuable bits of information and shared experiences that can't be found in those videos where you see someone tack-solder 20 components together with some inane music playing in the background. I've just learned to be myself, disregard negative comments and carry on with my presentations as I see fit, as IMO, the content is not about the presenter as much as what they are working on and how and why they are doing what they are doing to make things work.
I love watching your quality workmanship. The care and attention to detail that you take is an inspiration. I was always in far too much of a rush. My days of doing electronics are well past due to my bad health, so I enjoy it vicariously through your hands. Thank you.
12:00 Most PDF-readers allows you to select only a part of the sheet, and print only that and scale it to the full size of your paper. That way you can make it even bigger, and get rid of unnecessary things on the page.
Dalbani in just about every catalog had a reverse ECG cross. Had to be careful though and look up the specs for the suggested parts. Dalbani was a semiconductor parts wholesaler mostly catering to electronic repair shops. I saved those pages.
That board was a nightmare to work on! Reminds me of an "Expert" RF power amp, where the PCB holes were nearly same dia as component leads, and lead free solder, of coarse.. I will get the stainless pins you showed. Much carnage in your board.. I have the same old ECG sub manual, btw.. Nice, but I am careful when looking up an ECG sub and translating that to yet another one having the same ECG sub, of coarse..
Hi Tony, the different PCBs are odd - it looks like it's made up of two amps. I use a curve tracer (NI 210) to measure the semiconductors on the board. It has already happened to me several times that the diode test showed the correct values, but the curve was bent and the diode seemed to have added resistance. I bend the leads of the power resistors before inserting them into the PCB and create a small stop so that the resistors are fixed mechanically - I wanted to get pliers to bend the leads, but when I saw how much it costs, I continue to make locks using round pliers. The caliper for determining component lead spacing is awesome, never seen a tool like that - thanks for the demo - I have a fixed template (various sizes). Thank you also for showing the faulty parts on the schematic, so we can get an idea of what happened on the board - an excellent idea. Considering what faults you found and also thanks to the modifications you are planning, I can't wait for the sequel Nice day 🙂 Tom
Nice video, thanks. Can you share the brand and the model or part number for the tool you use to measure and bend component legs, the one that looks like a caliper?
Great video, I love your method of fault finding and working through schematics of these classic amplifiers. With schematics easily available I thought of using one to create my own boards and amplifier. What models would you consider to be classic? Something medium power class AB, or class A.
Hi Tony. At 6:22, you can make out a date (or at least the month and day), “Jul 12” near one of the metal can transistors with the black “starburst” heat sinks.
Hi Tony. I think perhaps a few more explanatory words would help those of us with impaired sight to understand what you are doing. I see you raising the schematic from time to time but no idea what you are pointing to or why and hand gestures are no substitute for the power of language. Thanks.
Merci for this nice video. Very pleasant this new mode. What happened to the card being so burnt out? Taker of the reference in your transistor book? You don't change the carbon resistors? The one on the right in particular. Sorry for my bad english...
All of these TO-3 (?) transistors and the arrangement is like ... ART :D Especially with the cooling-fins! Looks like monoliths. Thanks for the 2nd video! By the way, do you have any suggestions what one could look for to locate/reduce static noise? I have an old "Fisher AMP" with static noise (speaker and headphone) and it wont change much with the VOL-Slider ... its audible with 0 VOL and 100 VOL, with AUX, with Phono, Tuner ... input does not matter. Best wishes from germany!
I did several troubleshooting videos (Pioneer SX-750, SA-9100 and some others I can't remember at the moment) where I showed how I troubleshoot static and shot noise on a transistor. Although you can use a multimeter, it really shows up well on an oscilloscope.
A quick and dirty way is to find the collector of every (driver) transistor in the main amp (not the power transistors, they are not often noisy), and while listening, heat that wire/print pad for just one second with your solder iron. Most times the noise will go up significantly when you hit the culprit. ! Take care NOT to short out things... "Cold spray" (in a can, half a second on the body of the transistor) could be a follow up.
About these trimmer pots for audio gear: I never understood why the manufacturers used slider contacts for the middle contact instead of a fixed braided wire. You only turn them a few times in their lives, and then you have one of the two possible problem sliders out of the equation, and even the most problematic one.
Hi Tony, I have some question? for the 2n5415 - why did you search for a replacement ? 2n5415/16 are easy to find? Did I see right ? - the resistor in the current source r319 - burnt? how can that happen especially if Q306 is still ok? what does cr310 do? some kind of protection that cuts peaks off?
CR309 & 310 provide voltage limiting for Q403 & Q404 Primary driver transistors and provide a current path to the complimentary current source transistors Q309 & Q310. I searched for a replacement to show one method for doing so. I also didn't have the 5415 transistors on hand. The ones I found in my stash were essentially the same transistors. R319 was a 1/4 watt transistor. It did its job and failed (hopefully) before the transistor did. The shorted output transistors caused excessive offset and the diff pair was unable to compensate for it. This caused excessive current on Q306/Q305. Q305 is referenced to the negative DC rail and the shorted output/driver transistors placed excessive positive voltage at the base and collector of it. This made it not be a current source anymore and overloaded the resistor. This is just my best guess. I won't know if anything else is faulty for sure until I test it out. I want to see what happened, rather than just "shotgun" all the components.
@@xraytonyb thanks Tony FYI: you can test the board w/o the power pack - with some jumpers , says somewhere in the service manual Your failed transistors are the same ones that were super leaky in my 510. I wouldn’t be surprised if the two input differential amp xtor have very different gains 🤔
I don't understand why you just don't use a bank of capacitors Bank of eight capacitors instead of two filter capacitors much better way of doing it. you can use higher value if you put a soft start module in as well so you could run 100, 000mfd upgrade and put a 3 amp bridge rectifier in
It's not going to make any audible difference. 3 amp rectifier bridge on that amp? I don't think so and what's wrong with the old part or a direct replacement? The art of restoring a vintage amp is to not hack it up. Modifications to fix obvious engineering or detrimental old technology problems are fine, but this isn't one of them. JMO.
Hey there, Tony. Thanks so much for showing that PACE Lead Bender tool. I ordered one, and it makes fitting parts onto a PCB or even P to P wiring so much easier. Thanks again. I work in a shop repairing mostly guitars but also tube amps. Love your vids, because they’ve helped me with somewhat of a blind spot I had with repairing solid state gear as well. Just means more customers. 👍🔊😊🎶
I like the change in presentation, but maybe a little commentary on what is vibrating between your ears👍
I like your banter Tony!! The extra bits were nice to see...but "our conversations" are almost what I get most out of your videos! ..I won't stop watching ;-) I REALLY appreciate the time & effort you put into your vids!!! THANKS!!!!
Great watching and always informative, you could chat a bit more though sometimes even the rambling thoughts are helpful.
I agree 100%
@ 13:00 That output transistor configuration is more like a "Cascode" configuration, used by Nelson Pass in his Threshold 800A amp dating back to it's production in early 1975. If you notice, the transistors closest to the power rails are biased by their own resistor divider network, which is separate from the inner transistors variable bias , and the transistors being in series with the outer transistors being biased on already, helps compensate for the miller capacitance of the series connected transistors, giving them a higher fT / transistion frequency, then they would normally have (w2aew has a good video on this) The outer transistors AF base signal is then driven by the common output rail of the inner transistors closest to it.
I have a feeling that Tony had a person make a comment like I was presented with awhile back, that stated that I talk to much, so, we get the silent treatment. 🤣 All I know, in in the things he shares with us while chatting, he often drops valuable bits of information and shared experiences that can't be found in those videos where you see someone tack-solder 20 components together with some inane music playing in the background. I've just learned to be myself, disregard negative comments and carry on with my presentations as I see fit, as IMO, the content is not about the presenter as much as what they are working on and how and why they are doing what they are doing to make things work.
That needle desoldering tool looks handy. For 4 bucks shipped, got the set coming on the slow boat from china.
Estimated delivery date is May 3. Must be a really slow boat.
I love watching your quality workmanship. The care and attention to detail that you take is an inspiration. I was always in far too much of a rush. My days of doing electronics are well past due to my bad health, so I enjoy it vicariously through your hands. Thank you.
12:00 Most PDF-readers allows you to select only a part of the sheet, and print only that and scale it to the full size of your paper.
That way you can make it even bigger, and get rid of unnecessary things on the page.
That's really cool. Thank you Tony and have a great day!
Dalbani in just about every catalog had a reverse ECG cross. Had to be careful though and look up the specs for the suggested parts. Dalbani was a semiconductor parts wholesaler mostly catering to electronic repair shops. I saved those pages.
A start! Enjoyed.
That board was a nightmare to work on! Reminds me of an "Expert" RF power amp, where the PCB holes were nearly same dia as component leads, and lead free solder, of coarse.. I will get the stainless pins you showed. Much carnage in your board.. I have the same old ECG sub manual, btw.. Nice, but I am careful when looking up an ECG sub and translating that to yet another one having the same ECG sub, of coarse..
Hi Tony, the different PCBs are odd - it looks like it's made up of two amps. I use a curve tracer (NI 210) to measure the semiconductors on the board. It has already happened to me several times that the diode test showed the correct values, but the curve was bent and the diode seemed to have added resistance. I bend the leads of the power resistors before inserting them into the PCB and create a small stop so that the resistors are fixed mechanically - I wanted to get pliers to bend the leads, but when I saw how much it costs, I continue to make locks using round pliers. The caliper for determining component lead spacing is awesome, never seen a tool like that - thanks for the demo - I have a fixed template (various sizes). Thank you also for showing the faulty parts on the schematic, so we can get an idea of what happened on the board - an excellent idea.
Considering what faults you found and also thanks to the modifications you are planning, I can't wait for the sequel
Nice day 🙂 Tom
"The calliper for determining component lead spacing is awesome..." 👍🏼
Grate video Tony would like to see more videos like this.
Nice video, thanks. Can you share the brand and the model or part number for the tool you use to measure and bend component legs, the one that looks like a caliper?
I showed it in the video. I held up the case with the make and model number written on it.
Great video, I love your method of fault finding and working through schematics of these classic amplifiers. With schematics easily available I thought of using one to create my own boards and amplifier. What models would you consider to be classic? Something medium power class AB, or class A.
need talking Mr Xry
19:30 I ran into this problem with an Audiolab m-dac: high quality 4-layer board with an inner ground plane; a nightmare board to work on. 32:29 👍
Those first boards were made the day before my 11th birthday.
Then we are the same generation, I was already 11 years old in 2 months.😄
Thanks!
Hi Tony. At 6:22, you can make out a date (or at least the month and day), “Jul 12” near one of the metal can transistors with the black “starburst” heat sinks.
Looks like cold case for Tony to Solve.
Or an Epson Workforce WF-7620 for the tabloid printing.
Hi Tony. I think perhaps a few more explanatory words would help those of us with impaired sight to understand what you are doing. I see you raising the schematic from time to time but no idea what you are pointing to or why and hand gestures are no substitute for the power of language. Thanks.
Thumb up: good, thumb down bad, hand motion to the side: failed so throw away. He's just showing part number on schematic.
6:35 i see a partial date on the collector board, maybe . 6 - 25 ... upper right between the labels.
Merci for this nice video. Very pleasant this new mode. What happened to the card being so burnt out? Taker of the reference in your transistor book? You don't change the carbon resistors? The one on the right in particular. Sorry for my bad english...
All of these TO-3 (?) transistors and the arrangement is like ... ART :D Especially with the cooling-fins! Looks like monoliths. Thanks for the 2nd video! By the way, do you have any suggestions what one could look for to locate/reduce static noise? I have an old "Fisher AMP" with static noise (speaker and headphone) and it wont change much with the VOL-Slider ... its audible with 0 VOL and 100 VOL, with AUX, with Phono, Tuner ... input does not matter.
Best wishes from germany!
I did several troubleshooting videos (Pioneer SX-750, SA-9100 and some others I can't remember at the moment) where I showed how I troubleshoot static and shot noise on a transistor. Although you can use a multimeter, it really shows up well on an oscilloscope.
@@xraytonyb Thanks! Gonna check those videos!
A quick and dirty way is to find the collector of every (driver) transistor in the main amp (not the power transistors, they are not often noisy), and while listening, heat that wire/print pad for just one second with your solder iron. Most times the noise will go up significantly when you hit the culprit. ! Take care NOT to short out things... "Cold spray" (in a can, half a second on the body of the transistor) could be a follow up.
About these trimmer pots for audio gear: I never understood why the manufacturers used slider contacts for the middle contact instead of a fixed braided wire. You only turn them a few times in their lives, and then you have one of the two possible problem sliders out of the equation, and even the most problematic one.
👍
👍😍
Actually that is the smaller Weller
Is it muted? How did you make it completely silent?😛
Thanks😊
Outputs wired that way......isn't that somewhat discrete darlington....ish????
Hi, nice tool to measure component whole distances and bending tool , what is it called, where can I get one ? thanks
Yes, I want one too!
Hi Tony,
I have some question?
for the 2n5415 - why did you search for a replacement ? 2n5415/16 are easy to find?
Did I see right ? - the resistor in the current source r319 - burnt? how can that happen especially if Q306 is still ok?
what does cr310 do? some kind of protection that cuts peaks off?
CR309 & 310 provide voltage limiting for Q403 & Q404 Primary driver transistors and provide a current path to the complimentary current source transistors Q309 & Q310. I searched for a replacement to show one method for doing so. I also didn't have the 5415 transistors on hand. The ones I found in my stash were essentially the same transistors. R319 was a 1/4 watt transistor. It did its job and failed (hopefully) before the transistor did. The shorted output transistors caused excessive offset and the diff pair was unable to compensate for it. This caused excessive current on Q306/Q305. Q305 is referenced to the negative DC rail and the shorted output/driver transistors placed excessive positive voltage at the base and collector of it. This made it not be a current source anymore and overloaded the resistor. This is just my best guess. I won't know if anything else is faulty for sure until I test it out. I want to see what happened, rather than just "shotgun" all the components.
@@xraytonyb thanks Tony
FYI: you can test the board w/o the power pack - with some jumpers , says somewhere in the service manual
Your failed transistors are the same ones that were super leaky in my 510.
I wouldn’t be surprised if the two input differential amp xtor have very different gains 🤔
Hello Tony I am working on a Pioneer SX780 do you have a copy of the bottom of the main pc board on line part I need is missing
maybe just clean the pots
ASMR 'Lectronics Repair with Tony. ™
I make a terrible mime.......
@@xraytonyb LOL. Just let the.heater drone do the talking...
I don't understand why you just don't use a bank of capacitors Bank of eight capacitors instead of two filter capacitors much better way of doing it. you can use higher value if you put a soft start module in as well so you could run 100, 000mfd upgrade and put a 3 amp bridge rectifier in
what's your youtube channel?
It's not going to make any audible difference. 3 amp rectifier bridge on that amp? I don't think so and what's wrong with the old part or a direct replacement? The art of restoring a vintage amp is to not hack it up. Modifications to fix obvious engineering or detrimental old technology problems are fine, but this isn't one of them. JMO.