Hello, I was hoping someone might help me to choose some suitable good quality capacitors for my old SAE P101 preamp.
I bought it about 10 years ago, at which time it worked, but had quite a loud background hissing noise. So I put it away for later repair - which is now 🙂
When I plugged it in now, it did switch on, but no sound came through. Hmm, maybe stuck speaker relay I thought, and had a closer look inside: Here I quickly discovered, that it basically needs a complete capacitor replacement. Many have leaked, and the rest soon will I imagine.
(see pics)
So the question is, which caps to use?
Since this will take me quite a few hours of work, I would like to get the best possible result (within a reasonable budget). What would be the best to use for this unit? Nichicon Muse? Elna Silmic? Or...?
And should I use the same type allround, or eg. one type for the PSU, and another for the audio circuits?
Any assistance would be greatly appreciated 🙂
I bought it about 10 years ago, at which time it worked, but had quite a loud background hissing noise. So I put it away for later repair - which is now 🙂
When I plugged it in now, it did switch on, but no sound came through. Hmm, maybe stuck speaker relay I thought, and had a closer look inside: Here I quickly discovered, that it basically needs a complete capacitor replacement. Many have leaked, and the rest soon will I imagine.
(see pics)
So the question is, which caps to use?
Since this will take me quite a few hours of work, I would like to get the best possible result (within a reasonable budget). What would be the best to use for this unit? Nichicon Muse? Elna Silmic? Or...?
And should I use the same type allround, or eg. one type for the PSU, and another for the audio circuits?
Any assistance would be greatly appreciated 🙂
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Just what I was going to say. Larger radial caps are often held down with glue for mechanical reasons. Can you post a picture of the worst single case of a leaky cap. Lets walk through fixing the problem before cap replacement. It also looks like the outputs have been replaced at some point.
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jvhb,
I'm in the process of doing the same thing on that exact same version of the P101, do you have a schematic for that version? I have a schematic for the version without the TO92 transistors in the line stage, the rest of the schematic is real close.
For capacitors I used Panasonic FCs for power supply and decoupling, and Nichicon Muse for the bi-polars.
In your pictures there are no heatsinks on the TO92 transistors in the line stage, you might want put some on your parts list. They are the four transistors just about dead center on the PCB, close to the big black ribbon cables. One of the 2N5087s went noisy on me, heat related? Mine has heatsinks from the factory.
I'm also searching for some of the rectangular LEDs, one of mine lost it's tip, still works though.
Craig
I'm in the process of doing the same thing on that exact same version of the P101, do you have a schematic for that version? I have a schematic for the version without the TO92 transistors in the line stage, the rest of the schematic is real close.
For capacitors I used Panasonic FCs for power supply and decoupling, and Nichicon Muse for the bi-polars.
In your pictures there are no heatsinks on the TO92 transistors in the line stage, you might want put some on your parts list. They are the four transistors just about dead center on the PCB, close to the big black ribbon cables. One of the 2N5087s went noisy on me, heat related? Mine has heatsinks from the factory.
I'm also searching for some of the rectangular LEDs, one of mine lost it's tip, still works though.
Craig
Just glue you say! Well great if that is indeed the case 🙂
I'm no expert, but is still looks very suspecious to me. Look at the second picture, P1040400, in full size (not fit to screen).
This captures the worst area pretty well. The cap in the top left corner has a whole miniature river of brown stuff running on to the PCB. Is that really just very sloppy glue work? So much for the fabled SAE quality I guess...
But in any case, now that have it opened up, I would like to change at least all the larger caps in any case. So the original question stil stands: Which type(s) to use?
Craig, that is quite a coincidence! Can you post some nice nude pics of yours? Also the output section, which does indeed seem worked on in mine. Would like to know if the correct/best components have been used, or if I also have to replace these..
I have emailed Jim (the SAE guy) about schematics. According to his website, he has them for P101. Hope he will respond. Will definitely add the missing heat sinks also.
I'm no expert, but is still looks very suspecious to me. Look at the second picture, P1040400, in full size (not fit to screen).
This captures the worst area pretty well. The cap in the top left corner has a whole miniature river of brown stuff running on to the PCB. Is that really just very sloppy glue work? So much for the fabled SAE quality I guess...
But in any case, now that have it opened up, I would like to change at least all the larger caps in any case. So the original question stil stands: Which type(s) to use?
Craig, that is quite a coincidence! Can you post some nice nude pics of yours? Also the output section, which does indeed seem worked on in mine. Would like to know if the correct/best components have been used, or if I also have to replace these..
I have emailed Jim (the SAE guy) about schematics. According to his website, he has them for P101. Hope he will respond. Will definitely add the missing heat sinks also.
I got my schematics from him also so it will be a different version. What is the output section you are referring to? If it is the heatsink assy., that's part of the power supply, two series pass transistors for the regulated high voltages, + and - 28VDC and two monolithic regulators, 5VDC and 12VDC. I just pulled it all apart, cleaned, new mica insulators, and thermal compound.
I don't have a camera so no pics.
CRT
I don't have a camera so no pics.
CRT
To bad you don't have a camera. Would almost send you a cheap one, so so I could have a good look at your P101
jvhb,
I put it all back together and now have low output on both channels. The xsistors in the line stage I thought were 2N5087 and BC237. I only replaced the 2N5087s, the numbers were very faint and partially missing due to the heatsinks scrapping the numbers. Would you please check the numbers on your xsistors, they're the ones closest to the relays. Thanx.
Craig
I put it all back together and now have low output on both channels. The xsistors in the line stage I thought were 2N5087 and BC237. I only replaced the 2N5087s, the numbers were very faint and partially missing due to the heatsinks scrapping the numbers. Would you please check the numbers on your xsistors, they're the ones closest to the relays. Thanx.
Craig
Problem solved and it's all because of that damn glue. I replaced all of the rectifier diodes that were corroded from the glue. All of the power supply diodes were 1N4004s and I thought CR12,13,15 and 16 were also, well it turns out that CR12 and 13 are 11 Volt 1 Watt zeners. Without a schematic for this particular version I had to go back retrace everything I did and finally found two diodes that were marked differently, the zeners. It didn't help that all of them were the glass type, usually zeners stick out like sore thumb. They do now!!!!
Craig
Craig
One more thing I didn't realize, if the preamp is plugged in it's ON, 24/7 and those TO92 xsistors run very warm without the heatsinks. Get some heatsinks, I can tell from your pics that yours have already been replaced at least once.
Craig
Craig
I just found the zeners on the schematic, they're in power supply. In the amp they're not close to the main supply, oh well.
Craig
Craig
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Hi, I just noticed that something has gone wrong with my last post (#7). It was much longer - but I don't recall it precisely now :-/
I did have one idea/question: Would it be worthwhile to replace the problem TO92 transistors with TO220 types? These are stronger, and I could also fit a better heatsink with screw mounting. What do you think? - keeping in mind, that I would to keep this P101 running for decades still.
Also, I wanted to ask you if the transistors in the PSU section (on the black heatsink), look correct/good to you? They seem to have been replaced, so I just want to be sure that the right type (and quality) has been used..
Should probably mention, that I only have a basic knowledge of electronics, so I may need to have some things "spelled out" 🙂 I have done a fair bit of soldering over the years though, so am pretty confident in my ability to change these components. But fault finding, other than very obvious stuff, is beyond me. So not sure what a "zener" is, or what it does 😛
Do you have the schematic in electronic form? Could you perhaps email it to me? I haven't heard from Jim yet... I could probably (hopefully) make better sense of your last posts, if I had the schematics as support.
I will be glad to check any components on mine if you need me to, but you got the problem solved yes?
I did have one idea/question: Would it be worthwhile to replace the problem TO92 transistors with TO220 types? These are stronger, and I could also fit a better heatsink with screw mounting. What do you think? - keeping in mind, that I would to keep this P101 running for decades still.
Also, I wanted to ask you if the transistors in the PSU section (on the black heatsink), look correct/good to you? They seem to have been replaced, so I just want to be sure that the right type (and quality) has been used..
Should probably mention, that I only have a basic knowledge of electronics, so I may need to have some things "spelled out" 🙂 I have done a fair bit of soldering over the years though, so am pretty confident in my ability to change these components. But fault finding, other than very obvious stuff, is beyond me. So not sure what a "zener" is, or what it does 😛
Do you have the schematic in electronic form? Could you perhaps email it to me? I haven't heard from Jim yet... I could probably (hopefully) make better sense of your last posts, if I had the schematics as support.
I will be glad to check any components on mine if you need me to, but you got the problem solved yes?
Just remembered another question: Which model did you use to replace the "NONPOLAR" type caps by the phono input? Can you use the regular Nichicon KZ for this also?..
- not quite sure about the whole polar/nonpolar stuff 😕 - will have to do some reading on that ..
- not quite sure about the whole polar/nonpolar stuff 😕 - will have to do some reading on that ..
I can't answer your transistor question because I don't know exactly their purpose as the schematic different. There isn't much room in that area and you'd have to do some pin bending to get the TO220s to fit as the pin out is different.
I replaced all of the non/bi polar (the grey ones) with the bipolar Muse beacuse I had most of them in stock. I also had in stock most of the polarized ones in Panasonic FCs. I do a lot of repairs and the Panasonic FCs have most values and sizes covered.This is not an end all or super high end preamp so my choices were decent ones. I think I replaced 82 in total. If it was an all out attempt I would have ditched all of the ceramics in the audio path also.
The power supply xsistors/regs are as follows, left to right, 2SA1111, 2SC2591, LM340-12, and LM340-5. It probably looks messy because it's hard to get all of the pins lined up with the holes in the PCB.
PM me with your email and I'll send you the schematic.
Craig
I replaced all of the non/bi polar (the grey ones) with the bipolar Muse beacuse I had most of them in stock. I also had in stock most of the polarized ones in Panasonic FCs. I do a lot of repairs and the Panasonic FCs have most values and sizes covered.This is not an end all or super high end preamp so my choices were decent ones. I think I replaced 82 in total. If it was an all out attempt I would have ditched all of the ceramics in the audio path also.
The power supply xsistors/regs are as follows, left to right, 2SA1111, 2SC2591, LM340-12, and LM340-5. It probably looks messy because it's hard to get all of the pins lined up with the holes in the PCB.
PM me with your email and I'll send you the schematic.
Craig
PM sent..
Yeah I know this will never be a super high end preamp, but I like the look, and have the matching poweramp 🙂
The "ceramics in the audio path", is that all the standard little resistors with stripes on them? So if I wanted to go a bit further that just cap upgrade, that be the next logical step? And what would I replace them with? Metal film type? Can you point me in the right direction here?.. Specific product type/numbers would be great 🙂
Yeah I know this will never be a super high end preamp, but I like the look, and have the matching poweramp 🙂
The "ceramics in the audio path", is that all the standard little resistors with stripes on them? So if I wanted to go a bit further that just cap upgrade, that be the next logical step? And what would I replace them with? Metal film type? Can you point me in the right direction here?.. Specific product type/numbers would be great 🙂
The ceramic capacitors are the little tan colored discs, the pf sizes would be upgraded to silvered mica, and the uf values would be some sort of film capacitor. All of the resistors are already metal film so not much in the way of noticeable upgrade there. Schematic is on the way.
Craig
Craig
Hola, Tambien estoy restaurando un SAE P101, Tengo el manual de servicio pero parece ser de otra revison, Los transistores (Q15-Q14 y Q114-Q115) Que estan proximos a unos reles, En el manual de servicio no figuran, Estan compuesto por (BC237 y 2N5087) No se si son los originales, Alguien podria decirme si son los correctos de fabrica? Gracias.
Hi, I'm also restoring the SAE P101 unit, I have the manual but apparently another Revison, Transistors (Q15-Q14 and Q114-Q115) who are we coming one relay in the Service Manual are not listed are Compound ( 2N5087 and BC237) do not know if they are the original, someone could tell me if the right are made? Thank you.
Hi, not sure if I understand you correctly, but here is a picture of the small transistors (that run hot) discussed in the thread. A970/C2240. In my unit they were GR grade, but not sure if that is correct.
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