Issue with Mitsubishi DA-A30 power amp

[Enrico Fermi]

I bought a Mitsubishi DA-A30 power amp. It developed distortion on the right channel only. I took it to my local tech.He replaced both driver transistors 2SB382 and 2SD537 the transistor before the one driver 2SC1904 and the diff. amp dual FET 2SK109 . When he powers up amp it opens a junction on the 2SB382 driver transistor. He replaced 2SB382 again and it did same thing.If he powered up amp slowly the transistor would hold but if you did a normal start-up it would open the junction again on the 2SB382 driver transistor.Tech had amp for a couple of months with no success so I paid the checkout fee and the parts he replaced and got amp back..Any ideas would be a surely appreciated. Thanks, Bill

 

[petehall347]

what substitutes were used ?

 

[Enrico Fermi]

what substitutes were used ?

I believe tech used exact replacements but not sure. I will contact him. Thank you for the swift reply.

 

[Enrico Fermi]

I believe tech used exact replacement parts, but not sure. I will contact him. Thanks for the swift reply.

 

[petehall347]

ask where he got the replacements from as they are obsolete .

 

[DaveVoorhis]

Sounds like the replacement semiconductors are fakes and/or not up to spec.

 

[Enrico Fermi]

Tech claims he used exact replacement parts and they were hard to find. I will contact him again. The more emails I send, the more he is getting agitated. He has been an electronics tech for 30 plus years so I have no reason to doubt his ability. Every other piece I have taken to him for repair, he has been able to fix.

 

[Enrico Fermi]

Should I try another tech and explain situation to him and show him the parts that were replaced. The other tech did give me the parts he replaced and there are part #'s and name of manufacturer on them.

 

[Enrico Fermi]

Tech claims he used exact replacement parts and they were hard to find. I will contact him again. The more emails I send, the more he is getting agitated. He has been an electronics tech for 30 plus years so I have no reason to doubt his ability. Every other piece I have taken to him for repair, he has been able to fix.

Any fellow members in the KC. MO. who want this amp for free, please contact me. My name is Bill 816-308-6460

 

[Enrico Fermi]

Ended up taking amp to another tech in town.This was a big mistake.The guy ended up blowing up both channels and said it would cost $390.00 to rebuild both channels. Beware of Vintage Turntable & Stereo in Independence MO. After the fact, I read many bad reviews on yellow pages about this shop.