There are two of these caps labeled CP-C 0.1uf (k), 400wv nichicon Japan capacitor. After extensive searching I could not find out what the CP-C stands for. According to the service manual they are ceramic capacitors and are pictured in the manual so are the original caps. I have never seen ceramic caps that look like this. They like an axial electrolytic about two inches long but does not have polarity. I tried to upload an image on Imgur but for some reason it would not let me. It just looks like a standard Elna grey electrolytic axial capacitor. So why then would the service manual say it is a ceramic? It is connected from the number 1 and 2 power output transistors on the heat sink of my Sansui 3300 receiver to chassis ground.
I just got this link from IMGUR 
@john-barron I’ve never seen such a ceramic capacitors that look like this either. Which makes me think that they appear to be rather OIL filed capacitors, WV400 definitely stands for Working Voltage (400 Volts). I don’t Know what CP-C stand for but it could be anything in relation to the capacitor designation or some kind of grade such as long life, standard life, or some other parameters such as operating temperature, tolerance, etc. (just a wild guess)
PS: In my post above I meant to write OIL “film” capacitors (Not OIL filed). Here is typical example of an OIL film Capacitor:
https://ictrictr.tistory.com/6462
Note: The sleeving color shouldn’t have any relevance (I don’t think it has) (K) might stand for tolerance (10%)
@ovi4 Yes you are right about the tolerance. I did find out that it is a 10% capacitor and while I did find in many forums (which by the way I hate to get information from forums because mostly what you get is opinions and not facts) that this is not a ceramic and some recommended several alternatives I could not find on either forums or Nichicon or other manufacturer websites what exactly this is. I suspect it is not a ceramic and that the labeling in the service manual is incorrect. I just want to be sure of what it is incase I have to replace them that I don’t replace it with the wrong thing and burn out the transistors which are all good. One person on Audiokarma said it was a film cap and recommended to replace them with WIMA MKP4 0.1uf 400wv caps and said these are superior to the original CP-C .1 400wv caps. But how can I be sure? The link you provided does describe what I have. I suppose one option would be to pull one out test it and then cut it open to see what is inside. Or I could just replace them with the WIMA caps if need be and hope for the best.
Well, one thing I’m sure of: considering that these are 400V caps (I assume they are in the Pioneer SX939) and they work at a voltage way below their rated voltage chances are they are still good. But to find out if they are leaky or not you can employ the Cap Leakage Tester (if you still have in working order) and switch it to the forecasting mode). It would be interesting to know (since you did not mentioned in your previous post) where they are located as in: (what are the cap numbers written on the schematic) so we can work out what they actually do. As for WIMA caps “wima” is a German manufacturers and are known to make good quality caps MKP4 have a “Poly-Propylene Film” as dielectric (but no oil). And yes they make a good replacement candidate.
@ovi4 No these are not in the sx-939. The sx-939 is finished and it turned out to be a transistor that was put in wrong. Once it was corrected everything worked. but I could not do the alignment so I found someone about 80 miles from me that has a shop that can do the alignment and I sent it to him to finish it. Hopefully when he is done aligning it, it will be a great unit. This cap we are talking about is in my Sansui 3300 which I stated in my first post on this capacitor at the end of the paragraph if you go up you will see that.
The cap numbers are C023 and C023 on the schematic for the Sansui 3300. Here is a link to the schematic https://imgur.com/a/x94oYwU the caps are at the bottom marked C023 and C024. They are connected to the collector of the NPN output power transistors and chassis ground. I will pull a cap and test it. Will let you know what I find.
@john-barron fist of all, I’m glad that you finally managed to get to the bottom of the problem you were having with the Pioneer SX939 as when reading your capacitor enquiry post I automatically assumed that you are still working in it. 👍
Secondly, I had a brief look @ a copy of the Sansui 3300 Service Manual (that I already had on my PC). and it seems that C023, and C204 are in parallel with the main supply rail (one for each power amp. channel) suggesting that their role is to act as decoupling caps only! (to basically filter out any potential noise on the supply). I know that you were concerned in case they short they might take out some of the “potentially hard to find” original power audio output transistors but that won’t be the case. Being in parallel with the power rail, in the event that they go shorted or excessively leaky, they won’t do much damage to the amp at all. IE: if C023 goes short it would simply take down (burn) the protection fuse F002 (4A) and similarly if C024 goes bust it would simply blow the protection fuse F003 (4A). So, as you can see not much damage at all. If anything I’ll be far more concerned with testing/replacing the output electrolytic caps . C851, C852 (2200uF/80V) if needed. If they go short or extremely leaky they are the ones that could surely cause some serious damage either burning some “precious speakers” (by directly sending DC to the speaker windings) or destroying some power output transistors in the process.
@ovi4 Yup amazing how forgetting that the replacement transistor is not pined out the same and putting it in wrong can cause so such a headache. But you did point me in the right direction. thank you.
Sansui 3300
Ok so replace C023 and C024 with the WIMA MKP4 0.1uf 400wv caps or can I just use the yellow Illinois film caps of same uf and same voltage as I already have them in stock.
I planned on changing out C851, C852 and C018 1000uf 50v caps as they all tested either weak or bad. But what do you think about C016 the main cap coming off the bridge rectifier 3300uf 100v. I tested it in circuit with a tool called Capacitor Wizard which does in circuit ESR and it tested good. However I did not take it out of circuit and test it for leakage. Do you think I should just change it out because I’m doing all the other caps and it should be just good policy to do so or just leave it?
@john-barron for C106 as having 3300uF capacity testing it for leakage (with MCL’s cap leakage tester) would not be relevant as you’ll be spending forever to do it. MCL’s leakage tester is not really intended for caps bigger than say…100uF as MCL has actually said in some videos. Testing the cap for the actually capacity value IE: with your Brymen multimeter on capacity function would be a good idea.
Here is the thing: if you know the rated caps tolerance, take the capacity value with your Brymen. It has to be within the rated tolerance !. In case you read a capacity that is (NOT Lower!) but rather higher than the rated tolerance, then that is (9 times out of 10) a very good indication that the cap is leaky and it needs to be replaced, but if is within the tolerance I (personally) would leave it in circuit. As for the C023, C024 I would happily employ the Illinois caps since they are of a respectable trust and quality and, a very low leakage.
@ovi4 quick question I am looking for a replacement for this transistor 2sc281B and have found this on Mouser, part number 610-BC108B or manufacture number BC108B PBFREE from manufacture Central Semiconductor. Do you think this is a suitable substitution? The original is a T01 package and this is a T18 both are similar. Someone on Audiokarma suggested a T92 package transistor BC548B but they are no longer available and this T18 looks closer in specs but I could be wrong. link https://www.mouser.com/ProductDetail/Central-Semiconductor/BC108B-PBFREE?qs=u16ybLDytRYYe8zUrXDBlg%3D%3D Here is a link to the original transistor which is also no longer available https://www.datasheetcatalog.com/datasheets_pdf/2/S/C/2/2SC281.shtml
@john-barron It is hard to say for sure about an equivalent that it really works or not. Is always the case of try and see. It is sometimes equally important before any buying decision to actually know what equipment comes from where in that equipment is? Low noise preamp, power amp preamp, power supply regulation, electronic switch, timer, oscillator, buffer circuit, etc. and also the voltage it operates on that part of the circuit. This ultimately plays a big role in decision. I’ve literally just looked up Mouser and BC548B is available: https://eu.mouser.com/ProductDetail/Diotec-Semiconductor/BC548B?qs=OlC7AqGiEDlb2ZtlMo%252BmFQ%3D%3D
Now, looking at the specs datasheets for all 3 transistors it looks that both BC548B or BC108B are good candidates I cannot see a reason why not. However, I would go for a BC108″B” or a “C” because they are known to have the noise floor a little lower and also a better shielding since the capsule is made of metal and this is important when dealing with extra low signals such as phono stages or audio Cassette tape players or any minuscule signals for that matter.
PS: when fitting new equivalents always beware of the pinout. You don’t want to fall into that trap again. Do you ?… 😉
This is a schematic [img] 
[/img] showing the power transformer of my SANSUI 3300 with the output wires color coded Blue, Brown and purple.
See in the schematic it shows the Blue wires going to the Bridge rectifier with the Brown going to the F-1434 Board and one purple to ground and the other purple wire to 1434 board.
But that is not how it is currently connected. I noticed that when I bought the amp that it had been worked on before. It currently has the purple wires going to the Bridge Rectifier with one Blue wire one going to ground and the other blue wire going to the 1434 board and both Brown wires going to the 1434 board.
First since voltages are not shown on the schematic what should they be on Blue, brown and Purple wires with 120v going in to primary side ?
Second should I reconnect the wires according to the schematic, switching the Blue and Purple back to what the schematic show; Blue to Bridge and purple to ground and 1434 board ?
Thank you for any help.
@john-barron Hi John. If what you say is correct and that someone before you has indeed soldered the wires in the wrong order you should indeed put them back according to what is showing on the schematic. However, keep in mind that before any attempt you have to make sure that the transformer is the original one and not some kind of similar replacement (recovered from other similar equipment and that the colors just happen to be different but voltages are in fact correct. So first of all, what I would do is see if is any serial number or part number (combination) visible on the transformers body and look in the service manual to see if that part number matches. If it does then… that is a good indication that the transformer is in fact original. Now analyzing the power supply schematic there are some things you need to take notes on. The blue winding should be the one that would provide power for the Power amplifier module (F-1180F) since the filtering caps connected to that bridge rectifier have the highest voltage rating *100V DC so…in theory the blue pair should provide the highest voltage output between the 3 windings Id. say somewhere around 45 – to – 55V AC but if you have the service manual there should be some info regarding some testing points. If you look closely there are some circles marked with lettering as from A to…. so they are possibly testing points that the manual would most likely refer to. Going further the purple pair is only there to provide power to all the incandescent lights (nothing else) and you should measure somewhere in the ballpark of 5-7V AC. Now the brown-gray-brown combination/winding should feed all the rest of the modules : F-1267C etc., etc. and you should measure somewhere around 27-35V AC (brown to brown) and half of that if measured against Gray.
@ovi4 Ah I never thought to check if it is the original transformer. But it is, it says SANSUI with the correct serial numbers for the original so it is good. I pulled all the wires off and checked voltages for each color and here is what I got. Brown wires 68V ac, Blue wires 6.8v ac, Purple wires 54v ac and the Brown to grey 33.6v ac.
So does this mean that the color code on the schematic is wrong and that the purple wire should stay on the Bridge Rec? as the Blue is the only wires that have low voltage for the incandescent lights at 6.8v ?
And last why does the brown wires with the highest voltage 68v go to the 1434 board shouldn’t the highest voltage lines go to the 1180 board?
As for testing points the manual does have a section for that but all it shows is the points where adjustments are made and nothing on voltages. The letters and numbers in circles are just reference points that show where one point connects to the next point on the schematic where they are broken.
Or is it the case where the highest voltage is needed to drive the speakers?