Crate Blue Voodoo No Output

[CW4 Powell]

I am a soldier stationed at Ft. Gordon Ga. I have a Crate Blue Voodoo 6212 that suddenly went silent. The power lights illuminate as well as all the tubes. I checked the cable going to the speakers and it checked good. The speakers are wired parallel. I checked and replaced all the fuses (One of the fuses labled 1/4 amp Norm F2 was open). I checked for signal through the effects return (still silent). I plugged the effects send into another amp in an attempt to see if I could send a preamp signal to the other amp (still silent). I ohm'd R2 and R4 and they were in tolarance (470 ohms +/- 10% @ 5 watts) I pulled them out to isolate them they were within spects reinstalled (still silent). Replaced all tubes with known good (still silent). What gives??? Any help would be greatly appreciated. Thanks, Richard

[nosaj]

disconnecct your speakers and touch a 9volt to the terminals you should hear some noise if the speaker is good, no noise speaker is fried.

jason

[oc disorder]

Hi CW4 Powell and welcome to the forum.
After you try nosaj's suggestion which it could be , my musings are as follows
As F2 is in the cathode path at one of the output tubes
I suspect you had an internal short in one of the tubes which took it out.
Two things I would check first are:-
1. The bias supply (approx -62 volts at junction of C57 ,R103 & R111 and aprox
-50 volts pin 5 6L6 ) to make sure the new tubes don't cook ! redplate !!
2.The HT or high voltage supply (caution shock hazard)which may explain
why it doesn't work.

Aprox. 490 volts between the junction of D17,C48,R113 & R11 , and ground.
From this point there is a string of dropping resistors R115 620 ohms 3 watts,
R107 5K6 3 watts and R100 10k 2 watts. All these would most probably be
wire wound except maybe the 10 k.
At the end of the "chain" there should be aprox 320 volts D.C.
Again I should point out that this is a shock hazard.
If the H.T. is missing it's like having the amp permanently on standby!

The schematic is here
http://music-electronics-forum.com/t8494/
I am led to believe the Crate BV 60 is the same as the 6212.

Hope this helps
O.C.

[Amp Kat]

Make sure the HT fuses are not blown. There may be some fuses inside the amp that could be blown also which could have been caused by a bad tube so did good changing the tubes. It is also possible that the tube took out a screen resistor and opened up the HV feed. Either way be careful if you go inside as this is a monster amp and could have HV stored in the filter caps.