Sony XM-2252HX

[mike49504]

Im working on this amp.

I have a strange issue with it.

The amp has no output So i checked for rail voltage.

The outputs they are using are FX50SMJ and FS70SMJ.

Rectifiers

F10P20F
1:-52.1
2:-.03
3:-52.0

F10P20F
1:-0.3
2:52.2
3:-0.3

Outputs
FX50SMJ
1:0
2:-12.6
3:0

FX50SMJ
1:-14.5
2:-52.0
3:-12.6

FX50SMJ
1:-0.18
2:-13.2
3:-1.8

FX50SMJ
1:-15.0
2:-52.0
3:-13.3

FX70SMJ
1:1.8
2:13.1
3:0

FX70SMJ
1:14.7
2:52.2
3:13.1

FX70SMJ
1:15.2
2:52.0
3:13.5

FX70SMJ
1:1.8
2:13.5
3:0

Any ideas on what i need to check for since this amp has no output and different reading on the outputs??

[Perry Babin]

This amp uses a cascode output configuration. The voltages you have appear to be OK. You need to trace the signal through the preamp section to the amp section.

I'll assume that you've tried running all of the controls through their entire range and confirmed that the op-amps have both positive and negative supply voltage.

[mike49504]

Ok thanks Perry,

I found a bad solder joint amp works again.

[ppia600]

Those are powerful amps, seems like they should have a great reputation but you can get them for pretty cheap.

[Perry Babin]

Don't buy one that has (or possibly has) shorted outputs. No direct replacements are available (as far as I know). PacParts shows the OEM parts. They're $45.78 each.

[glen65]

Originally Posted by Perry Babin

Don't buy one that has (or possibly has) shorted outputs. No direct replacements are available (as far as I know). PacParts shows the OEM parts. They're $45.78 each.

Will these work?
FS70SMJ-2

FX50SMJ-2

[Perry Babin]

They appear to be identical to the original part numbers.