5150 evh fuse F3 f4

[Blosterc]

Hi Enzo and thank you very much for your time!!
now the pot seems to work fine. but I have very low sound and the bass mid treble and post lead, does not work ...
pre and amp seem disconnected .... in fact the preamp out is similar in volume (low and without eq) ..
also the v4 valve seems to be off ... and there is hum at low volume .. I replaced v4 and it made a lot of light ( like a light bulb) with high volume hum..

I can bypassed K3 relay with connect pin 2and 4 for have signal out return?
I would like to test the power amp...
Because k4 and k3 look dead.

[Blosterc]

P.s. the rhythm pot... is removed ... but the pot lead post , started to burn ...
immediately i have rotate it... and stop burning...

[Enzo]

Now with the pot removed, did you try measuring for voltage on the holes where the pot used to be?

[Blosterc]

Hi, no because connection under main board...
but I can connect three cables for measuring..

[Enzo]

You know, the legs of the pot might be soldered under the board, but each one connects to some other part, and the parts have leads on top of the board you can probe.

[Blosterc]

Hi,

I measured ... zero on all three pins .. also on other pots. the only one is post lead:
pin 1-2 = -25v
pin 2-3 = +25v
pin 1-3 zerov

[The Dude]

Test post (please ignore).

[Blosterc]

Hi, 0v... On three pins..
I Have measure on j56 j67 about 48v
About 20v on jack foot switch (jack not fully inserted)..
about 10v on power relay (k2c, k1c) and about 2/3v on k3c...(not switch) and K4 0v (not switch)

All tube light on... Led all on...
But only hum Maybe preamp tubes fail?
I have test with 10 12ax7.... But only hum..
I would like test power amp... But k3 not switch...

Thank you

[Blosterc]

Hello ,
news:
fuses do not burn,
touching pin 6 of v5 with a tester, I hear the sound, if the ecc83 in v5 is inserted halfway, (as if not to make contact with the second valve half) hum disappears and a good volume is heard.(check ground of V5?)
however bass, mid, treble do not work ..
doesn't work post gain Thank you

[g1]

Schematic attached.
I'm not sure what you mean about 'v5 inserted half way', with the series arrangement of the heaters, that should make V1,V2, and V5 all stop working I think.

[Blosterc]

Thanks for schematic!
Sorry.. i have inserted "half way" V3..not V5..
So, i think without pin 6/7/8....
Now fully working without tone stack and light hum...
check all way of V3?
Thank you

[Blosterc]

Good morning,
can anyone tell me why c14 or c60 (also C13 and C10) on the diagrams are capacitors and instead on the amplifier they are resistors?
and if I go to measure c14 or c60 the measure is open ??
Thank you

[Helmholtz]

They measure open because they are caps.
Small value caps can look like resistors.

[Blosterc]

ok but these are not resistors(first photo)?

[Helmholtz]

It's not possible to tell from looks.
When they measure open, they are no resistors and from the circuit, resistors wouldn't make sense in this place.