Need help with output transistor layout Marantz 1200!

daveyh

AK Subscriber
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Years ago I pulled the output transistors from my Marantz 1200. Now I cant remember how they were installed. I am going to put some NPN--- MJ21194G and PNP - MJ21193G in to replace the old ones but need to know which ones go where. I have misplaced my notes and can't find anyone who has taken pictures of how they were installed online.

I have included a picture below of the layout left to right.

Can someone help me please....
 

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Not sure if this helps, but Bob Speece (wlhd1610) rebuilt my 1200. Here is a before and after pic of the outputs that Bob sent me. Unfortunately, I can’t read the after pic. If you can determine which is NPN and which is PNP, the before pic might help. Otherwise, check with Bob. He can probably tell you.
Steve


Left amp before
op before left.jpg



Left amp after
op after left.jpg
 
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If I recall correctly the left side amp board had the pnp’s on top with the two npn’s on the bottom and the right side were the opposite (boards are mirror images but reversed in actual mounting).
That would put the two npn’s on top and the two pnp’s on the bottom on the right side amp board.
Don’t forget that there are around 6-8 Technical Service Bulletins to do/check on the 1200.

Bob
 
I found that the 2520’s are the PNP and the 2519’s are NPN, so sounds like Bob’s memory is pretty good.:D
 
Great. Thanks guys!

Bob:

Can you tell me where I can find the Technical Service Bulletins?
 
Got it fixed! Had to rebuild the right amplifier board with updated driver transistors because of obsolete parts.
 
Awesome! Are you going to do a complete rebuild?

I've already recapped both amplifier boards, the phono board, power supply, the rectifier board and installed a new relay. I also put in all new output transistors. I have had this and worked on it to long. Time to move on to another project. :)
 
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I've already recapped both amplifier boards, the phono board, power supply and rectifier board with a new relay and installed all new output transistors. I have had this and worked on it to long. Time to move on to another project. :)
:thumbsup:
 
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