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Ok thanks for that info. I have just checked and he has them both listed currently so I will tack some on to my fuse lamps order.

I have commonly seen KSA1381 and KSC3503 mentioned as subs for the uniwatt transistors. Are you able to comment which would be better suited out of these and the pair you suggested?

Thanks I will add those subs for the uniwatt transistors to my order list. Ah yes I do remember encountering a failed 2sc984 biasing transistor in a Pioneer sa-1000 I repaired recently, I can’t remember what I replaced it with in the end. Interesting to know that Affinity for artifacts had some...

That certainly looks much tidier. The large pigtail fuses are definitely very crammed. Yes sorry, I meant the service bulletin revision appears to have been applied on this board. The more I read about this driver board the more I learn about it’s issues that need addressed. I will indeed just...

I know these are failure prone and it’s a good idea to replace them all so I will likely end up doing this as a precautionary measure. For the purpose of fault finding I did lift the leg of a few on that right channel to test their value and the ones I checked seemed pretty close. I will indeed...

Trimpots are still original, their operation still seemed quite stable however maybe that ones minimum resistance has drifted. I think I will indeed just replace them all regardless. I will also check the value of some more resistors in that part of the circuit. All other components on the board...

Last week I finally bought myself a 9090 receiver locally. After a quick inspection and audition I handed over my dollary doos. However when I got home and set her up it quickly became apparent that there was an issue with the left channel, audible crackling/popping/humming that I didn’t notice...

Thankyou very much for all of your knowledge and guidance with this project, it was greatly appreciated! Definitely a learning experience for me, luckily a very rewarding one in the end. Just to summarize this whole thread for anyone reading along: The amp initially had a high bias issue in...

Ok firstly I must apologize as I broke the rules again today, I powered it up and…. It lives once again!!!! I had a rare child free/work free day so I decided to make the most of my time. I replaced all the shot transistors with the new ones I had on hand as per the subs previously listed. I...

The replaced transistors at Q12 & Q14 are both testing fine, I do have a couple of new spares for those too. I have new ksc3503d’s to replace Q8, and I have 2 new outputs plus 2 good old outputs that I can use for the time being. The only thing I’m missing is something to replace Q10 with.

Ok I’ve managed to spend some time with the amp today and I believe this is where we currently stand: Q16, Q18, Q10 and Q8 are all dead. All resistors on the board test within 2-3% of rated value. All other transistors and diodes appear to test ok.

I had a few spare minutes last night after work so I had a quick poke around and discovered that Q10 appears to have failed. I pulled it from circuit and it’s identifying as 2 diodes in my component tester and showing shorted on the dmm. Whether this was a result of the main issue or the cause...

Haha yes I am absolutely willing to accept direction and I regret my 'gung ho' decision to power it up yesterday.. Just to confirm, the cooked channel now is the 'even numbered' side of the board. I did ensure both bias trimmers were set to minimum before powering up. So the resistors you would...

So.. my parts order arrived the other day. I installed all 4 new drivers on heatsinks with isolators as per the above subs. I installed 2 new outputs on the right channel (to replace the cooked ones) but left the 2 original outputs on the left channel. I did not yet replace Q5, Q6, Q7, or Q8...

Ok thanks for that, I will place an order over the next couple of days. Yes I was shocked at the price of the TO-3 devices! The MJ21194g was even more expensive but out of stock most places. I have gone through testing components and it appears to be only Q12 and Q16 that are shorted. I’m fairly...

Hello @markthefixer , I hope you had an enjoyable Christmas.. Just wondering if you have had a chance to review the SA-1000 transistor subs at all? I’m looking to put in an order with digikey at the moment as I need some parts for another amp also. I’m looking to go with: 2sc484 > ksc2073tu...

I don’t understand exactly what you mean about the ground being split? But I will read up about it. I haven’t replaced any capacitors in the amp at all yet, just some transistors on that main amp board so far. Thanks for the link to the filter caps, looks like they might be my only option...

The ac/dc coupling switch made a very slight difference to the offset temporarily but not much. I believe I did check it with the pre amp disconnected previously but I will check that again too. Last time I was testing it was getting to around 300mv on the left channel, I put the amp aside for a...

Ok thanks for that, yeah I did suspect that if the leaky filter cap was to blame it would likely affect both channels but I wasn’t certain. I did actually start looking online for replacement filter caps and they do indeed seem quite hard to find, most stores (mouser/ digikey etc) seems to be...

My 1152dc is reading very high dc offset in the left channel from the speaker terminal. It climbs to almost 1vdc within a few minutes with the trimpot at minimum position, the right channel is ok. So far I have replaced all 2sa872 & 2sc1775 transistors on the main amp board with closely matched...

Ok no problem, thanks for that. Yeah all good, I’m in no rush now so I appreciate you taking the time to look into it. Either way I’ll be waiting for delivery which is going to be shocking right now as you said. The only local stores I have are Jaycar or Altronics but their stock is limited and...

I found an old SA-1000 BOM list on here that states the following subs: 2sc484 > ksc2073tu 2sa484 > ksa940tu 2sc1080 > mj21194g or mj15024g Are you able to advise is these are still the most suitable subs or if there are any better suited ones available? I notice ksc2073tu is a to220 case so...

Sorry I think I initially said the right channel was the problem channel but it was actually the left channel. (The one with odd numbers was the faulty channel) That’s what makes this latest episode most confusing, Q11 tested good but Q12 tested as a resistor. But the apparent good transistor...

I’ve had a very puzzling and tragic turn of events.. I pulled Q11 & Q12 and tested them in my little component tester. Q11 (the bad channel) tested fine but Q12 (the good channel) was reading as a resistor somehow. I decided to switch them regardless, turned it on and connected my meter. The...

Yes I believe I took that set of transistor voltage readings that morning and then swapped out the outputs that evening, the glue Pioneer used on the mica washers was a real pain to remove too! Ok yep I shall swap Q11 to Q14 from side to side this evening. If that has no effect I can measure a...