Memphis 16-MCD1500 repair help

[Perry Babin]

Where on the secondary side do you read 2.5v?

Are there any shorted output FETs?

 

[Lerch256]

 

[Lerch256]

Reading 2.5v on those legs off the transformer... Have 12v on the other side ....

All the fets are brand new .. I tested all of them before I installed to make sure .. thanks

 

[Perry Babin]

What voltage do you read on the shields of the RCA jacks?

Re-check the FETs. If there is a drive problem, the FETs can fail immediately when the amp is powered up.

Do you have a scope?

 

[Lerch256]

Ok I'll remove them and check .. I do have a scope .. I'll check and see what I have one rca jacks.. thanks

 

[Lerch256]

Ok so I removed all the output fets.. they all checked good on my tester .

I had accidentally soldered a bleed resistor in front of one of the fets to another and bridged that so that's where the fault was coming from

Now I have drive on one side and not the other.. so I swapped out the drive cards and it has drive on the other side and not the other...

So I figured the problem in in this drive card... I removed and replaced all the transistors.. still no drive .. I've narrowed it down I believe to an inductor .. but I don't know what size it is to be able to purchase a replacement

 

[Lerch256]

That's it .. it shows up bad .. I removed the one from the other card it test good or at least says it's an inductor.. see pic 2

 

[Perry Babin]

11uH?

After zeroing your meter, check resistance out of the board. You may want to pull multiple with the same markings to confirm readings.

Your tester may not have enough resolution to determine the value.