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.
I still have one issue that needs resolving. I performed an in circuit
diode test across D809 and D810. They both read 105 ohms (regardless of
the polarity of the probes). In essence, connecting either one of those
diode's terminal with one probe and then connecting the other to ground
yields that same 105 ohm reading. On the other side of that bridge diode
circuit, D811 and D812 yield normal front to back in circuit diode
readings. Desoldering any of the components is quite a chore because of
the double-layered board. I am stumped trying to figure out the
troubleshooting path of least resistance here. I haven't ruled out that
the 105 ohm reading may just be normal but my gut feeling says it's not.
Thanks for your reply.
--
David Farber
Los Osos, CA