Replacing Transistors in AKAI PS-200M

[Vlad_9_]

Hello,

My father has an Akai PS-200M amplifier that was broken for a long time.

Manual: https://www.google.com/url?sa=t&rct...e-Manual.pdf&usg=AOvVaw02BuNeixx956kpqqjDq80S

He's trying to repair it now. His friend inspected it and we need to replace 8 transistors. He said we should get 2x 2SB645 and 2x 2SD665 per channel. Here's the image from the internet. This is not our image.

Now, I can't find 2SB645 and 2SD665 in Europe. I've only found them in China and I'm afraid to order from China because of the stories about fake and low quality transistors. But I've read that instead, we could use MJ21195 and MJ21196. Here:
http://audiokarma.org/forums/index.php?threads/replacing-transistors.601895/
Also mentioned on another forum for a Marantz 2330B receiver.
Also, looking at this image above, it's low res but I think that the code for the lower-right transistor begins with MJ211... ?

I just wanted to check here if you think it's ok to use those transistors instead for this AKAI as well. And if so, does anyone know of a reliable/reputable place to buy them in EU or USA?

I've found them at Digi-Key, USA. Are they ok? The shipping cost is a bit high because I'm in Europe but it's bearable.

Thanks for reading, hope someone can help.

 

[Bratwurst7s]

Hi Vlad, welcome to Audiokarma. I can't help you with your question about the 2SB645/2SD665 but I can state that DigiKey is a reliable and trustworthy supplier. I've ordered from them many times and they are always fast and there are no concerns with them regarding fake parts. If your order is €50 or more shipping is free to Europe. Usually I receive my order in 3 to 5 days here in Munich. The same goes for Mouser. I like them even better than DigiKey because they accept payment with PayPal and use FedEx, so I usually have my order in my hands in 2 to 3 days.

Cheers,
James

 

[Vlad_9_]

Thanks James! I'll take a look at Mouser too.

 

[slimecity]

There wont be any issues getting new genuine MJ21195 and MJ21196 from the big suppliers like Mouser, Digikey.

However before replacing transistors outright, you really should test the original transistors in the Akai, out of circuit, to ensure that they are actually causing the problem.

 

[avionic]

MJ21195 and MJ21196 from the big suppliers like Mouser, Digikey.

Concur..

 

[avionic]

His friend inspected it and we need to replace 8 transistors. He said we should get 2x 2SB645 and 2x 2SD665 per channel.

Sounds like the shot gun approach to me.

 

[avionic]

Welcome to AK Vlad.
I hope the friend knows what he is doing. Just out right replacing the output transistors. Usually doesn't get the job. done. Thats a good chunk of coin that may not fix the "root cause".

 

[Vlad_9_]

Yes, father's friend is doing repairs of amplifiers so I guess he knows what's he doing. He did say he needs to replace more parts but he already has those.

I have contacted the guy who did the repair seen at the picture in my first post, He says he did indeed use MJ21195G and MJ21196G. So I've ordered them from Mouser.

Thank you all for advice. I hope it all works fine in the end

 

[nick_ville]

I

Yes, father's friend is doing repairs of amplifiers so I guess he knows what's he doing. He did say he needs to replace more parts but he already has those.

I have contacted the guy who did the repair seen at the picture in my first post, He says he did indeed use MJ21195G and MJ21196G. So I've ordered them from Mouser.

Thank you all for advice. I hope it all works fine in the end

I'm sorry to drag up an old thread, but I also have an old PS 200m amp that is in need of repair. I had the amp at a shop, but they didn't spend the time to get it fixed in the end. I think they have replaced the output transistors, and some other parts, but I'm waiting to receive the amp back and have someone else look at it. Were you guys able to get the amp up and running? I'm curious as to the root cause of the problem, blown transistors, etc. Thanks in advance!