Peavey 6505+ preamp tubes not glowing faint sound

[g1]

Post #5 has the heater circuit for what this amp is supposed to be. Looks like parallel arrangements, maybe the 2 branches are in series?
Nothing common to V3 & V6 heaters.

[Enzo]

Post #5 has the circuit for the 6505+ 112 COMBO, Redline reports he has a 6505+ head, which has series DC heaters on the preamp tubes.

[Amp Kat]

Should be easy to figure which one you have. If you pull one tube and the others go out you have series connection. On the schematic Peavey gives the total number of VDC so take that number and divide it by the amount of tubes and that is the voltage drop across each tube. If you go to each tube (with them all in ) and measure voltage across pins 4 & 5 you should get that voltage. If I'm not mistaken that amp runs 12.6 vdc on the preamp tubes but not positive about that. Also believe they run a 50 volt elevation circuit on pin 1 and the splitter tube or at least the 5150 did so if you find that voltage that's what it is but it would be from ground potential.

[g1]

Post #5 has the circuit for the 6505+ 112 COMBO, Redline reports he has a 6505+ head, which has series DC heaters on the preamp tubes.

Sorry Enzo, I mistakenly figured if it were the wrong version, someone would have pointed it out by now.
Can we get the correct schematic up in here?

[Jazz P Bass]

This should be the same.

5150 Head.zip

[Enzo]

That's a 5150 COmbo.


Here:
http://bmamps.com/Schematics/Peavey/...ice_Manual.pdf

[Redline]

So how can 2 tubes not be getting heater voltage and the rest are in series? That's really frustrating. Could it be the actual tube sockets?

[Jazz P Bass]

I reread this post.

I thought that you stated that V1 was not receiving the proper voltage.

Which 2 are out?

[Redline]

I reread this post.

I thought that you stated that V1 was not receiving the proper voltage.

Which 2 are out?

I was wrong. V3 and V6 are out.

[Enzo]

Four of the preamp tubes are wired in series across the two 24v supplies, two across +24v, and two across -24v. The other two run on AC 6v.

If you look at the schematic, V3b heater is wired to -FIL, which is -24vDC. Now look down at V3a, where the other end of the heater is wired to FILA. FILA is just a drawing shortcut, it is pin 5 of V6, then pin 4 is the other end of V6 heater, which is ground. SO V3 and V6 are in series between -24v and ground. The other two are wired similarly across +24v.

It is of course possible you have a bad socket, but I really would first suspect R49 in the power supply. That is the resistor between the real -24v supply and the -FIL. 4.7 ohms.

[g1]

And swapping around tubes the problem stays with those sockets?
Have you resoldered those sockets?

[Redline]

And swapping around tubes the problem stays with those sockets?
Have you resoldered those sockets?

Yes and I did resolder all sockets.

[g1]

And the resistor Enzo mentioned in post #25 ?

[Redline]

And the resistor Enzo mentioned in post #25 ?

Just checked r49 and it's fine.

[Jazz P Bass]

First off, have you checked the fuses?

If good, break out the voltmeter and verify that +FIL is +24 Vdc and -FIL is -24Vdc.

Peavey_EVH_5150-II_Heater Voltages.pdf