How and where do you guys find schematics that you need to get a job done?
I have made a post here and one in the other schematic Usenet newsgroup for
alt.binaries.schematics.electronic, plus a couple of web boards and have
come up with nothing.
So do you make a polite request in a Usenet newsgroup (Which one(s)? Or
post a request on a web board or forum, if so which ones, or do you just
give up and scrap the job or try to work without it. Many jobs can be done
without them but someimes you really have to have the service manual or at
the very least, the schematic diagram.
Right now I am doing a "Carver Creation" with that Carver "magnetic field
core" power supply; a Sunfire True Subwoofer Super Junior that has a blown
amplifier in it. Both F1 & F2, 4A 250V fuses are open and the output
transistors, Q7 2SC3181 & Q11 2SA1302 are shorted. I have cut these
transistors from the board and they are indeed shorted. The MOSFETS; Q10,
Q12, Q21, & Q24, IRF640, appear to be dead shorted between main terminals 2
& 3, the gate on terminal 1 averages about 160 ohms to the main terminals 2
&3. I have removed them from the board for further testing and found that
two of them were indeed shorted. The good news is that I have tested with
my Fluke meter some of the small SMD components near the output section and
can find nothing burned, shorted, or open. Everything else looks good but
for the two large output transistors, 2 of the TO220 MOSFETS, and 2 GMA 4 A
fuses.
I am afraid to try to fire this thing up when fixed because of that Carver
"magnetic field core" power supply, I cannot variac it up slow and watch
the current nor can I use a 100 watt light bulb in place of the main fuse.
It seems to be a matter of replace the for sure bad ****, check all around,
pray, keep fingers crossed, plug it in and watch for smoke.
Any ideas on how to get the schematic, service manual, or tips on working
on this small beast? I am between jobs so I cannot afford to just buy the
service manual, even if it were indeed available.
--
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