Phonic 1062 mixer amp,2006

1 channel only Elektrotanya SM is for the linear ps version and also lacks the power amp schema in full etc, no other schema found. I've not tried powering up since on receipt , removed from the cab. Exploring cold first. As ps rails are paralleled for the PAs, the ps must be ok. What are the 2 black epoxied lumps labelled POD1062X that look like epoxied torroidal chokes. But according to the (wrong) 1062 version schema they are an IRFP250, presumably 3 pins, 1 pin obscured. Rail switching between 40V and 70V rails + & - on power demand. Anyway cold testing , seemingly as inductors , one is s/c and the other o/c which explains why a toroid with 2mm diameter wire wrapped around it can be o/c with no hot spot,at least, to be seen. So if mainly a powerFET, what else , not suggested on the schema, would be under the epoxy? in this pic with red Xs all o/p devices test cold DVM-D ok, so a shorted rail switcher makes sense and goes into protect mode on one channel but there is 2 of these POD1062X per channel and only 2 here, unless 2 in one pack, explains the difference in overlays , other than the POD number , also different datecodes on each, but would require 6 pins each then, 4 hidden. Will power up on the bench and then remove all those screws to explore the hidden side of the board

That PCB looks remarkably similar to the one I recently repaired in this item:

You might have more luck with a studiomaster schematic than I did, I only found a useless partial copy, but I didn't look very hard as the problem was the output relays. One had no continuity anywhere, the other was intermittent, so I suggest you change both whilst you are in there.

This is what was in the Studiomaster:

This might confirm or deny my suspicions they are the same PCB.

Cheers,

Gareth.

1 channel only Elektrotanya SM is for the linear ps version and also lacks the power amp schema in full etc, no other schema found. I've not tried powering up since on receipt , removed from the cab. Exploring cold first. As ps rails are paralleled for the PAs, the ps must be ok. What are the 2 black epoxied lumps labelled POD1062X that look like epoxied torroidal chokes. But according to the (wrong) 1062 version schema they are an IRFP250, presumably 3 pins, 1 pin obscured. Rail switching between 40V and 70V rails + & - on power demand. Anyway cold testing , seemingly as inductors , one is s/c and the other o/c which explains why a toroid with 2mm diameter wire wrapped around it can be o/c with no hot spot,at least, to be seen. So if mainly a powerFET, what else , not suggested on the schema, would be under the epoxy? in this pic with red Xs all o/p devices test cold DVM-D ok, so a shorted rail switcher makes sense and goes into protect mode on one channel but there is 2 of these POD1062X per channel and only 2 here, unless 2 in one pack, explains the difference in overlays , other than the POD number , also different datecodes on each, but would require 6 pins each then, 4 hidden. Will power up on the bench and then remove all those screws to explore the hidden side of the board

IIRC, In the Studiomaster, X and Y were just 2 toroid chokes, but not covered in epoxy.

No hidden transistors there.

Gareth.

Looks as though those black lumps will remain a mystery,I powered up ps and pa and test feed passed through both ch. So unless an intermittant problem in the pa , problem is in the mixer part, along with absent phantom supply, so off with all that mixer hardware instead of all those pa screws