Transistor sub question... I'm confused, again...

S

silverHalo

Member
Moved on to rebuilding the EQ Amp board....
The transistor listed are 2SC632A-71, 2SC632A-81 (see board layout pic.) I believe they are Sony transistors ... I can find the data sheets for 2SC632A but nothing with a -71 or -81. Their cases are slightly different, but I can't find any documentation on either. Anyone know about these little guys?
I can get original 2SC632A's, will they work????
Thanks!
 

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sH, That might be a date code, 71,81. Sanyo seems to also have made that transistor. I just googled the number, as you probably have too. I gleaned this looking at the suffix #. Dave
 
The Data sheet says the Sony made them.. but haven't been able to find a Cross-reference database for Sony. Would be nice if they had semi-conductor website for referencing things like this.
 
Upon further research, I found that TR601 & TR602 are really 2SC458's (at least thats whats on the board now). The third error I've found in the service manual so far. I guess when I'm done with this receiver I will release an updated and definitive 5000x Service Manual with all the corrections.... sheesh. The TR603/604 are marked with the 71, and the TR605/606 are marked with the 81 underneath the C632A marking. It seems like a date code, but I've never seen date codes listed in a service manual before. What gives??
 
The 2SC458 is the highest-failure small-signal transistor in the history of audio. They develop collector-to-emitter leakage big time.

I generally replace them with 2SC2240 or 2SC1345.

Best,

Fred Longworth
 
silverHalo said:
Moved on to rebuilding the EQ Amp board....
The transistor listed are 2SC632A-71, 2SC632A-81 (see board layout pic.) I believe they are Sony transistors ... I can find the data sheets for 2SC632A but nothing with a -71 or -81. Their cases are slightly different, but I can't find any documentation on either. Anyone know about these little guys?
I can get original 2SC632A's, will they work????
Thanks!
Click to expand...

Hi,
The (optional) suffix ndicates that the type is approved for use by various Japanese organisations while the last 2 nos. are either for commercial purposes or date of mfg. I believed the nos. -71 or -81 will be of no importance on the transistor performance (also these digits are never mentioned on any JIS book transistor manuals).

Regards!

http://www.engplanet.com/redirect.html?3809
http://www.necel.com/en/faq/f_tr.html#0002
http://www.elexp.com/t_tranmk.htm
http://www.qsl.net/yo5ofh/doc/transistor_codes.htm
 
silverHalo said:
Upon further research, I found that TR601 & TR602 are really 2SC458's (at least thats whats on the board now). The third error I've found in the service manual so far. I guess when I'm done with this receiver I will release an updated and definitive 5000x Service Manual with all the corrections.... sheesh. The TR603/604 are marked with the 71, and the TR605/606 are marked with the 81 underneath the C632A marking. It seems like a date code, but I've never seen date codes listed in a service manual before. What gives??
Click to expand...

Here are my findings with the Japanese substitution manual and are equivalent to each other:

2SC632A Sony
2SC458 Hitachi
2SC1815Toshiba
2SC1685 Matsushita
2SC900 NEC
2SC1740LN ROHM

Regards!
arsenio
 
Thanks for all the great information everyone!
Looks like I'll just go with the regular 2SC632A's and then swap out the 2SC458's with either the 2sc2240's or 2sc1345's recommend by Fred. We'll give it a shot and let you know what happens! Thanks again!
 
silverHalo said:
Moved on to rebuilding the EQ Amp board....
The transistor listed are 2SC632A-71, 2SC632A-81 (see board layout pic.) I believe they are Sony transistors ... I can find the data sheets for 2SC632A but nothing with a -71 or -81. Their cases are slightly different, but I can't find any documentation on either. Anyone know about these little guys?
I can get original 2SC632A's, will they work????
Thanks!
Click to expand...

I don't know what SilverHalo ended up doing here, but I do have in hand a revised version of the schematic, one that reflects the replacement driver boards (F-6013) in lieu of the original faulty boards.

For the board SilverHalo mentions, my schematic indicates:

Tr601 and 602: 2SC458LG(c) or 2SC632A-71

Tr603 and 604: 2SC632A-71

Tr605 and 606: 2sc632A-81

In other words, whoever wrote this didn't believe that the -71 and -81 suffixes were just date codes.

Also: I don't know that this thing is an EQ board. I think it's the phono stage.

Ecaroh.
 
Phono preamps have EQ (according to RIAA) in them to correct for the way vinyl records are made versus how the music should sound. So sometimes they're called EQ boards. Can't help you on the transistor suffixes.
 
noveltone said:
Phono preamps have EQ (according to RIAA) in them to correct for the way vinyl records are made versus how the music should sound. So sometimes they're called EQ boards.
Click to expand...

Yeah, the RIAA = EQ thing crossed my mind later. The term EQ board is new to me; I somehow guessed he meant tone controls. Thanks.
 
I'm having some problems with TR601 & TR602. Can you tell me what you used (all transistors on that board) and how were the results? Thanks
 
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