On 26/05/2014 23:32, Gareth Magennis wrote:
"N_Cook" wrote in message ...
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
http://www.diverse.4mg.com/phonic1062.jpg
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:
http://www.studiomaster.com/product-...xer-series/57/
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:
http://uk.farnell.com/jsp/search/pro...sp?SKU=1333638
This might confirm or deny my suspicions they are the same PCB.
Cheers,
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