SA-9900 Output transistors + Refurb help

If you need to replace an STV-3H, there is a seller on eBay located in Germany who carries them (item 321845661752).

You will also want to be careful with the AEX-003 posistors which are equally fragile.
do you recommend I change them as well ?
 
Sajjad, I am just finishing a SA-9900 restoration of all caps and transistors from LesE's BOM list. The restore went well and it's a great sounding amp. I'm chasing a small hum gremlin at the moment before i call it complete.
If you need any photos or reference measurements let us know.
 
Sajjad, I am just finishing a SA-9900 restoration of all caps and transistors from LesE's BOM list. The restore went well and it's a great sounding amp. I'm chasing a small hum gremlin at the moment before i call it complete.
If you need any photos or reference measurements let us know.
Thank you ever so much for your kind offer. If you have taken any pictures during the process they will certainly help me.
Thanks
Sajjad
 
i do not have foil side of Amp card. I'd need to open it up again. I'll see if i can get it in the next day or two.
From what i remember there was only one wire jumper on the foil side, joining D15 to D19 replicating the trace along the top edge of the card. The balance of the foil was as shown in the Service Manual.
 
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i do not have foil side of Amp card. I'd need to open it up again. I'll see if i can get it in the next day or two.
From what i remember there was only one wire jumper on the foil side, joining D15 to D19 replicating the trace along the top edge of the card. The balance of the foil was as shown in the Service Manual.

That's Ok, but no need to make a special trip into your amp. I just thought maybe you already had a shot of it saved.
 
i do not have foil side of Amp card. I'd need to open it up again. I'll see if i can get it in the next day or two.
From what i remember there was only one wire jumper on the foil side, joining D15 to D19 replicating the trace along the top edge of the card. The balance of the foil was as shown in the Service Manual.
Thank you very much for the pictures. Very helpful. I can now comfortably work on mine.
 
If you need a hi res version of a picture send me your email address on a private message.

the service manual recommends removing the secondary front face plate to service the preamp cards. I didn't, but in in hind sight is probably a good idea. Either way works.
 
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Would some one please guide me.

Power Supply board AWR070
Power supply regulators have been replaced by BD911 and BD912
Should I leave them be or change them to something more suitable ?
Also is there any way to check the power supply before connecting everything together?
Thank you
 
I think I'd use the BD911 and BD912 transistors for now as long as they aren't blown. They are rated at Pt=90W @ 25C, ft=3 MHz and Ic=15A which should be more than adequate IMO.

You pretty much have to reassemble the amp in order to test the power supply. Besides, you really want to have the power supply outputs loaded as a proper test.
 
I am still waiting for parts from Digikey, delayed due to adverse weather. I have not given up on this project as yet.
 
Dear All, I have almost re-build it and have following 3 questions, please help
  • What goes on Pin 7 of protection board?
  • What goes on pin 2 on power amp board?
  • thee are 2 light pink coloured wires coming from PIN 4 of PS board, one is connected to Pin 5 of AWR 77 and other was tucked under by previous owner/repairer, where should this wire be connected?
DBT is ready and I am itching to fire it up once I find out about above issues.

Many Thanks
 
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@Hipocrates thank you, question not 1 and 2 answered.
regarding question no 3, there are 2 light pink wires coming from AWR-070 Pin 4 and one of them is going to AWR 0770, Pin 5, where does the other pink wire go ?
once again thanks a million
 
Dear All, I have almost re-build it and have following 3 questions, please help
  • What goes on Pin 7 of protection board?
  • What goes on pin 2 on power amp board?
  • thee are 2 light pink coloured wires coming from PIN 4 of PS board, one is connected to Pin 5 of AWR 77 and other was tucked under by previous owner/repairer, where should this wire be connected?
DBT is ready and I am itching to fire it up once I find out about above issues.

Many Thanks

Wire connections between the boards are laid out in both the block diagram and the schematic of the service manual.
 
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@glen65 , thank you for all your help so far. Its not that I am being lazy, I cannot decipher it. I can trace it to AWR-077 but on the right fork it just does not make sense to me. Please guide me. Thanks
 
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