Pioneer RG-1 transistors

[Oldskoolfan]

Recently worked on my RG-1 upgrading caps and transistors, deep cleaning etc...
Had purchased a resto kit off ebay (first apparent mistake). All the original transistors are NLA so substitutes were supplied as follows;

KSC1845 for 2SC1312
KSC945 for 2SC945

No substitute was supplied for the 2SA725 transistors.

Found KSA992 for 2SA725 was recommended by people on that other site (2nd apparent mistake).

While the unit appears to be functioning, the meters are constantly pegged with no input signal.
My gut tells me that KSA992 is not a good substitute.

Could someone take a look at the subs and let me know if these are the best substitutes?
I kept all the old transistors so I can put them back in if no betters sub is available/recommended.

Thanks, Harold

 

[sweatybetty]

Apparently the 992 is the best replacement
https://audiokarma.org/forums/index.php?threads/2sa725-726-transistor-question.724890/
992 pin out shows ECB
https://www.onsemi.com/pdf/datasheet/ksa992-d.pdf
Where 725 shows BCE
https://www.alldatasheet.com/datasheet-pdf/view/1164012/ETC1/2SA725.html

Are you sure that the new 992's are installed correctly?

 

[Oldskoolfan]

Apparently the 992 is the best replacement
https://audiokarma.org/forums/index.php?threads/2sa725-726-transistor-question.724890/
992 pin out shows ECB
https://www.onsemi.com/pdf/datasheet/ksa992-d.pdf
Where 725 shows BCE
https://www.alldatasheet.com/datasheet-pdf/view/1164012/ETC1/2SA725.html

Are you sure that the new 992's are installed correctly?

Yes, but if I did get them in wrong I got them wrong on both channels. I will go back and look again.

 

[Oldskoolfan]

Figured out my problem on my RG-1

I had 6 KSC945 transistors in wrong because the pinout on the datasheet did not match the actual transistors.
KSC945 datasheet pinout shows 1. Emitter, 2. Base, 3. Collector. Actual test of transistors showed 1. Emitter, 2. Collector, 3. Base which matches the 2SC945 pinout.

Had to pull and test all 6 to verify. Wound up pulling 6 KSC1845 (2SC1312 replacement) and 6 KSA992 (SA725 replacement) as well to test/verify pinout which were as per datasheet.

Anybody else run across errors like this? I guess i'll start doing QC checks on parts when I order them.

 

[laatsch55]

All the time....

 

[Syborwolf]

How did it sound after the recap and transistor change? I have one on my bench, just replaced all the caps and noticed a lot of the transistors have blackened legs. I figure I better change them now too.

 

[Oldskoolfan]

How did it sound after the recap and transistor change? I have one on my bench, just replaced all the caps and noticed a lot of the transistors have blackened legs. I figure I better change them now too.

Sound seems cleaner. More open. No more "pumping" and improved gain.

 

[WOPL Sniffer]

How did it sound after the recap and transistor change? I have one on my bench, just replaced all the caps and noticed a lot of the transistors have blackened legs. I figure I better change them now too.

yep, if the transistors have black legs, get em out before the shennanigans begin. We have found that this black "corrosion" will eat the legs and it's usually where you CANT see when they have been eaten through.

 

[wattsabundant]

yep, if the transistors have black legs, get em out before the shennanigans begin. We have found that this black "corrosion" will eat the legs and it's usually where you CANT see when they have been eaten through.

Yep, same here. That is one of few exceptions to my rule that semis are run to fail. I see people buying these repair kits on EBAY and change out every transistor and diode. Changing out diodes and transistors that haven't failed does not improve reliability. The potential damage to the board and infantile failure negate benefit.