12002: 2" OT

[Strat78]

Did you resolder that 100k V3B plate resistor, it looks like it might not be making a connection at the turret with the 82k.

[vh junkie]

Check your HT fuse. Post your power tube socket voltages. Also voltages at the 2w 10k resistors.

Basic power flow:
Diodes, Fuse, Choke, Screens, (2) 10k res, PI, through sleeved wires on board to next 10k, etc.
From memory... think this is right... find out where the power is interrupted on its way to pin 1 on the preamp tubes.
When checking for heater glow, look thru the holes in the sockets...

[vanhalen5150]

Did you resolder that 100k V3B plate resistor, it looks like it might not be making a connection at the turret with the 82k.

Yeah did that. No change.

[vanhalen5150]

Check your HT fuse. Post your power tube socket voltages. Also voltages at the 2w 10k resistors.

Basic power flow:
Diodes, Fuse, Choke, Screens, (2) 10k res, PI, through sleeved wires on board to next 10k, etc.
From memory... think this is right... find out where the power is interrupted on its way to pin 1 on the preamp tubes.
When checking for heater glow, look thru the holes in the sockets...

With no power tubes in I dont have any voltage on the power tubes. The HT fuse looks fine, but Ill have to get another to try. Nothing at the 10k's.

Changed testers and put new batteries in both.

Do I need to lift things from the board to test for continuity? Start at secondaries from PT? I may need to lift the power board as well to check the wires on the bottom. Should have put those on top as well.

[vanhalen5150]

Odd because I was getting really high voltages on 2 days ago. Didnt leave it running for long that way, just a minute. Could the caps be smoked?
Only thing I changed was the 470K to a 470ohm resistor last night. Then nothing.

Booked the weekend for "amp recone diagnosis".

[vanhalen5150]

The only voltage on the power tubes sockets is the DC voltage bias at -42. Bias resistor/diode is about 100 AC.

[vanhalen5150]

With lights out looking into top holes of preamps, only the v3 is glowing. Shouldn't all 3 be if the heater wires are at 3.0 vac?
On v1 pin 1 there is still nothing. If I flip on the standby, voltage starts to climb quickly, from 0 to over 200. Didn't wait to see if it levels out somewhere.

[vh junkie]

Who made your OT? The wiring looks correct for a Marstran, wrong for a ******. Should not have done any damage, unless you had the power tubes in... You can check you HT fuse with an ohmeter... SB 0 ohms

[vanhalen5150]

It's a ****** OT. It's wrong?

[vh junkie]

Scratch my previous thought about the Marstran.
My 12xxx is a ****** 1.5" with the red/white going to the tubes.
Strat78 12xxx is a ****** 2" with the red/brown going to the tubes.
So yeah, its probably wrong.

[vanhalen5150]

Really? I'll check that out Junk. I thought I had that correct.

Canadian Thanksgiving weekend. Gravy and amps for me.

[Strat78]

Hold on, isn't that Chris's 2" OT? The wire codes I posted were for Chris's OT.

[vh junkie]

Yep, Chris' 2"... I think the OT wires should look like your pics... not mine cause mine's a 1.5"...

I did not see your posting for the OT, just the PT.

Might be able to check with a an ohmmeter... the "power tube wire" to "power tube wire" reading should be twice that of either "power tube wire" to the "center tap"(B+ wire)... power tubes must be out to check this...

[vanhalen5150]

I don't think I understand what you mean.

[vh junkie]

Which part?

If you have a two inch ******, it should be wired like strat78s:
Red/Brown going to the power tubes, white to the HI-V.

These wires form the center tappped primary of the OT.
SHould be:
Brown(tubes)->White(CT, HI-v)->Red(tubes)
As such the resistance from Brown to Red should be twice as much as from Brown to White, or White to Red.