On Thu, 1 Oct 2020 15:21:36 -0700, David Farber
wrote:
On 9/21/2020 8:55 PM, David Farber wrote:
On 9/21/2020 12:00 PM, legg wrote:
On Mon, 21 Sep 2020 09:57:39 -0700, David Farber
wrote:
On 9/21/2020 8:34 AM, legg wrote:
On Mon, 21 Sep 2020 09:59:22 -0400, legg wrote:
On Sun, 20 Sep 2020 22:17:29 -0700, David Farber
wrote:
Actuslly, the second relay looks more like a line voltage
selector. It will close for line voltages below 180VAC.
It looks like this unit isn't power factor corrected.
If that's the case, then you could do a quick fix by
relocating the voltage select relay to the inrush
position, short out the old voltage select relay
contact position, then place a large sticker on
the back indicating "100-130VAC INPUT ONLY".
RL
What an ingenious workaround! I'll definitely check out that relay swap
option.
By the way, the user informed me the model was not purchased in 2000. It
was purchased in 2009. There is a schematic for that year but it looks
incomplete to me. I've uploaded it to:
https://app.box.com/s/ch670hnsrtoswqhebtrye95n2vw5ktre
Thanks for your reply.
The following schematic covers models:
DCM1540L
DCM2000L
DCM3000L
DCM3800L
B2000 Rev J
https://cdn.shopify.com/s/files/1/04...0revj.pdf?2645
It has a line input and power stage looks similar to the
one you're fooling with, but I don't see a tube section
inserted anywhere.
You can wade through other Carvin docs:
https://carvinaudio.com/pages/power-amplifier-schematic
The older B2000 had a 60Hz transformer power supply, unlike
your unit.
RL
That's a great find. I wonder if the schematic I found earlier in my
research,
https://cdn.shopify.com/s/files/1/04...feb10.pdf?2161
interconnects with this new one you found.
Thanks for your reply.
--
David Farber
Los Osos, CA
Schematic is he
https://cdn.shopify.com/s/files/1/04...0revj.pdf?2645
I finally was able to figure out where all the power supply components
were hiding. They were obscured by the heat sinks. The culprits were
Q800 and Q802. Their part numbers are STGW30NC60W and they were both
shorted across all three terminals.
Check the gate components, if the fets fail. They don't always
survive.
The primary housekeeper around Q803 should run independently, with big
fets out of circuit, so you can check basic control and drive circuits
without a lot of risk (taking in mind it's still a primary-connected
circuit.
RL