ANYONE FAMILIAR WITH THE MCS 3125??

Rex Runner

Tobes of Hades lit by flickering torchlight
Replaced the filter caps
Large watt resistors in area of rectifiers got hot
replaced 2 of them
Still in protect
 
Does this model have transistor outputs or STK outputs?
 
Ok, I'll try to help you out, but if this is over your head, I recommend taking the unit to a repair shop.

First, Check voltage at your filter caps. Make sure BOTH sides have their +/- 63 volts. If you do not, turn unit off and locate the short (either wiring to the Amp boards or something with the amp boards or outputs)

Second, we need to see if there is DC coming from the Left or Right outputs. If there is, you have issues with the amp section of that channel.

Third, is there approx. 14 volts after R553 (100K) on the board?

Ill post a schematic that will help guide you
MCS 3125 schematic 4.jpg
 
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Because R553 is standing up and down to save space I can only read 1 side which is 63v
 
Why did you replace the filter capacitors? If it's in protect it's likely got a problem on the amplifier board (shorted outputs, drivers, etc.) rather than the power supply.
Resistors are fine to get hot if their job in the circuit is to drop a lot of voltage. My amp has a few that get over 120f but that's what they are there to do and they are within their rated wattage so no need for worry.
 
Filters caps were bulging and leaking
Worst set I have ever seen
Ill post pics
 
Ive read several threads on AK where replacing diodes and/or transistors on protect board was the issue. 2 of the resistors got so hot it melted the solder underneath
 
Those have definitely vented. Add those to your shopping cart.
 
I may not have measured correctly
You sent (2) photos of test points
Am I measuring the (2) lugs in each photo?
Or measuring (1) lug from each photo?
OR. Each lug to ground
 
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