Another Identifying Transistor Help Thread

[badwithnames]

Hello all,
I'll be doing a few restorations (SX-950, SX-880, SA-8800) in the near future and have been doing a lot of learning here on the AK forums. I've got a decent parts list going for all my projects but am having issues when it comes to what exactly I need to be replacing for semiconductors so I'm here looking for guidance.

Firstly, how does one know which transistors are common points of failure or faulty? Next, how do I go from a transistor part number in the service manual to finding a suitable replacement on say digikey or mouser? And lastly, how/what should I be testing for in the currently installed, potentially failed transistors? I've got a Fluke 77 that "should" be able to test diodes but if I need to get a specific tester for transistors I don't mind. For example, I grabbed an Atlas ESR70 because the fluke wasn't cutting it to properly test the capacitors.

Another question that I had is in regards to choice of capacitors (can create another thread if warranted)... while doing my replacement parts list I came across a few different audio specific series from Nichicon and was wondering if anyone had used them and their thoughts/concerns, specifically with the bi-polar in signal paths. UES (bi-polar, High Grade) vs UKZ (Premium Grade) vs UFG (High Grade Standard) vs UKA (High Grade Audio Equipment, Wide Temperature Range)
https://www.nichicon.co.jp/english/products/pdfs/e-ues.pdf
https://www.nichicon.co.jp/english/products/pdfs/e-ukz.pdf
https://www.nichicon.co.jp/english/products/pdfs/e-ufg.pdf
https://www.nichicon.co.jp/english/products/pdfs/e-uka.pdf

Thanks in advance!

 

[markthefixer]

Atlas ESR70.. hmmm good choice (i have one)
may I suggest an eventual Atlas peak DCA55 or DCA75 as a semiconductor tester.

Transistors are never tested in-circuit.
resistors are better read with one leg disconnected.

The lists represent the best efforts of experienced techs and what they have observed elsewhere and here about failures.
Some are rather infrequent - until it hits YOU...
Then there's "reverse engineering", figuring out what they did and maybe inferring what they had in mind. That's usually a BSEE level thing.
It's also why Pioneer may use the same transistor number in two different places, and the recommended replacements in the list are DIFFERENT from each other.
Different things are demanded of each.

Transistors are "cheap" - especially considering the effort need to disconnect something misbehaving off the shelf and open on a bench somewhere.
Then there's the wear and tear of digging through the unit just to GET to the things. Might as well just do it ONCE.

The lists (older) are a bit less convenient, parts series have been discontinued, others are out of stock with long lead times.

Go to the Tuning Fork section, and read it thoroughly. Read it again a year from now and you might be surprised at how much more you get out of it.
It was intended to get the techs out there a little better "tuned" to Pioneer. The technical "ground rules" as it were.

 

[12344321]

I recommend you start with this series. Its long, but it will get you going better than any one of us csn explain.

 

[badwithnames]

Atlas ESR70.. hmmm good choice (i have one)
may I suggest an eventual Atlas peak DCA55 or DCA75 as a semiconductor tester.

Thank you! I was looking at the DCA55 or DCA75 but didn't know if there were better options from other manufacturers, might as well pick one up with all the work I've got on my bench. I came across a recommendation for the ESR70 from a blog called "Oleg's Vintage Audio". He does a great job describing and documenting his process, I feel very lucky he's already done two of the three units I'm restoring.

Transistors are "cheap" - especially considering the effort need to disconnect something misbehaving off the shelf and open on a bench somewhere.
Then there's the wear and tear of digging through the unit just to GET to the things. Might as well just do it ONCE.

This is exactly what I'm thinking, I only want to do this once. As you know it's tedious work to remove each board and ensure everything goes back in it's proper place, so I'd prefer to replace everything I can while I've got them removed. I've done basic capacitor swaps and I plan on replacing all caps while I'm in there, I just don't know if I should be attempting to do all the semiconductors as well.

The lists (older) are a bit less convenient, parts series have been discontinued, others are out of stock with long lead times.

I noticed this so I plan on uploading my more recently updated BOM's once I'm done. Still deciding on which series of capacitors I'd like to use for electrolytic.

 

[badwithnames]

I recommend you start with this series. Its long, but it will get you going better than any one of us csn explain.

I appreciate the video very much! I'll give it a watch tonight.

 

[badwithnames]

Go to the Tuning Fork section, and read it thoroughly. Read it again a year from now and you might be surprised at how much more you get out of it.
It was intended to get the techs out there a little better "tuned" to Pioneer. The technical "ground rules" as it were.

Thanks again for pointing out this gem! Holy cow, I initially pulled that up and saw the first attachment about resistor codes and didn't think twice about it. Moved right on past that thread and on to my searching. Grabbing all of these right meow!

 

[larryderouin]

Marks rule of thumb is a bit old (dated probably 20 years plus now) . Each type is correlated to a Pioneer "type" in para's. I've been using it as a guide for over 15 years now, and my rehabs/restorations/rebuilds all are still going strong. This listing is NOT ONLY for PIONEER. I've used it on Sansui's, both S.S. and Tubed, 50's and 60's FISHER Tube and Solid State, Allied 395, various consoles (Magnavox, Zenith, RCA, etc.)

If you can't find a UPW/UHE in a size, look at the UPW datasheet, and it'll give you alternatives in the same family (UPS, UPV, UPM etc.) Same with pretty much any Nichicon cap. Pull the datasheet's and sub in that family as needed.

ECQ's are almost extinct. WIMA MKP/MKS are damn good subs. Small, cheap, work very well, and popular.

MARKTHE FIXER Cap rules of thumb (nichicon)

I use upw, uhe for general caps including signal coupling in that order depending upon stock "cea"
I use ues, uep & uvp in that order for bipolar depending on stock
I use ukl for low leakage caps (in sensitive areas they reduce the noise floor)"ceanl", "cssa", "csza"
0.1uf to 2 uf I use stacked film where they fit: DFS and ECQ

solid aluminum and tantalum caps get stacked film when possible, or ukl's otherwise. "cssa" "csza"

c?B means it's an axial cap = one lead on each end
c?a = radial = both leads on one end