CR-820 output transistor locations.

Either the SM is wrong, or the last chop shop installed them wrong.

Does anybody have a pick of their installed outputs without the heat sink covers on?

I am at home on meds for relaxation because of a heart/stress issue, and they make me loopy.

Any way, any help would be appreciated.

Rob

Take it easy Rob. Hope you get that heart/stress under control..

avionic said:

Take it easy Rob. Hope you get that heart/stress under control..

Click to expand...

Thanks.

Rob

Hello ROB

You are right, regarding indications in service manual :thumbsdn:
But it is very easy to know what is right and what is wrong :scratch2:
Just delete all the 4 output transistors ( 2SD427 or 2SC1403 for NPN type ) and ( 2SB557 or 2SA745 for PNPtype) .
Take your voltmeter and put the black (-) to ground and RED (+) to each collector on each power transistor socket :yes: . Switch the power on and note wich collector has positive voltage (this is for NPN = +42V) and negative voltage (for PNP = -42V)
Easy !
Make a mark with an adhesive tape on both positive and switch the power off .
Then discharge the electrolytic cap in the power supply( with a resistor ! never made short circuit ! :nono . Put the right output transistors at the right place and now switch the power on !

With the front of the receiver at the right, they are oriented (left to right) SD427, SB557, SD427, SB557. So a 557 is at the front, 427 at the rear.

Here are the centre two. Receiver front is to the right...



Hope that helps!

Thanks for taking the time to reply and take/post pics.

Rob

happy to help!
:thumbup:

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