Sansui G-8700DB Output Transistors Replacement?

buglitter

Member
Hi all,
I need your advice on this one. I just found out that my Sansui G 8700BD has two different sets of output transistors. One is TOSHIBA 2SD551/2SB681 on one side, and the other is D733/B697K (I believe) is made by SANYO DENKI.

Two 2SB697K are bad, and I wonder what would be the best option for replacements?

I am tempted to get two 2SB697 listed (as old stock) on eBay, but afraid of getting some counterfeits. However if I were to replace with MJ21193G/ MJ21194G, do I have to replace all 8 outputs?

Appreciate your input!

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Going to new on-semi pairs is fine. While its nice to have the same on both sides, you only need to do the 4 on the damaged side. I would not recommend recommend just replacing the 2 bad 2SB transistors. You should also make sure to check the drivers, and any other transistors and diodes on the bad side for failure as a result of the bad outputs. Check the large emitter resistors (0.47, 0.33 etc) and any others that look overheated, or are the fusable type. Usually resistors that fail in the amplifier are in the 4.7 ohm, 10 ohm, 120 ohm, 180 ohm ranges, as a result of a shorted or leaky transistor.

Good luck
 
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Thank you both!
I have decided to do a full restoration, and I am planning to replace all outputs with MJs. Mouser is currently out of MJ21194G until May, so I will have to wait a while. I probably will get those from Digikey. Meanwhile do you have any suggestion for the parts? I really want to rebuild the power supply with more beefy components so this monster would last at least another 20 years.
 
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