Blue voodoo problem... unbelievable!!

[zeegler]

I'm stepping out for dinner and a movie, but when I get home I'll respond in depth to this. Have you checked the internal fuses yet?

That's the first thing you should do for sure. Discharge those caps, and get a meter in there starting from the power cable. Just check continuity (remember to have the power and standby switches in the ON position and the amp unplugged though) You might get lucky and find a break in the circuit somewhere.

[Cygnus X1]

Well, my opinion is this.
Don't touch anything and get a bench estimate.
Define your terms (in dollar amount), and if it is out of reach then get it back and we will work on it.

Good or bad, the BV series is a good bang for the buck amp, one of the few that Crate really did OK on.
In other words, though it is tempting, don't mess with it until you get an estimate from a shop.

And, if you need a comma, I'll give a few, for free.

[warlok]

Yes, I checked the fuses. The schematics only show 2 each 1/4 amp, 250 v but mine has 4 (all good). And then the white one is the 6.25 amp slow blow on the schematic. Can't see through it (it's solid white), but it shows continuity (reads just over 1 ohm) on my meter. How do you know when that one is blown? Just check with a ohm meter? Or does it turn white when it blows? I've never seen a white fuse before.

EDIT: Just realized the schematic I have is for a BV60. The 1/4 amp fuses must be for the lights behind the tubes (2 for a BV60, 4 for a 120). Got the schematic for the BV120, white one is a 10 amp, not 6.25.

[Cygnus X1]

White colored fuses are usually higher rated, like 5 amp or more.
The white is a protective coating to protect against heat.
If the fuse is showing continuity then it is generally ok.

[warlok]

OK. I called tech support and they gave me a few things to check. I (very nervously) chased the power all the way through the circuit board. For some reason, the standby switch works now but no tubes or lights. With all knobs at 10, it's got 472 volts going into the output transformer (red, blue, and brown wires at the board) but nothing coming out to the orange green and black wires. Anyone who saw schematic can see what I'm talking about. So sounds like the output transformer is bad but I'm gonna call crate and verify that tomorrow. They do sell them and are in stock (drdestruction - if that helps you too).

The one thing that's bugging me is if I have voltage (460-ish volts) going into the tube board, and the same coming out, why are the tubes/lights not working/glowing? It goes into the output transformer after the tube board... I don't get it.. What am I missing? I had the voltmeter's black lead clipped to the case ground. Is it possible that there's a bad ground on the board and the circuit is open but I was able to read voltage because I was using the case ground?

[Cygnus X1]

That sounds about right for a B+ reading on the OPT.
Humor me:
With the power off:
Choose one of the power tubes.
Whatever on is easiest to reach the pins cleanly-make sure you aren't contacting anything but those two pins.
(Pin 2 is the second one counting clockwise looking at the bottom of the socket from inside the amp starting with the indexing tab. Same with pin 7. Just count clockwise).
If the socket is surface mounted or you can't see the tab then set your meter to ohms and look for continuity between two pins. They should have low resistance-normal. If they are 5 pins apart from each other then you found them. Be careful there is high voltage DC around there!

Clip a lead on pin 2. Now clip the other lead on pin 7.
Use alligator clips if you can!
Set your meter for a 6V reading range.
Now turn the power on.
You should have about 6.3 volts AC (or DC) between pins 2 and 7.

If you don't, then the heaters aren't working.

[warlok]

Hey Cygnus. Do you mean the pins on the tube itself? I don't see how I can do that with the tube installed (mounts flush in socket). I can either pull the tube and probe into the socket holes. Or I can see plainly the bottom solders of the tube sockets and the 2 junction things with 13 pins each (where they pin through the board). I can check there without taking anything else apart. Will that tell you what you're looking for? I can do that when I get home.

Is the "heaters" the "filament" on the tube board schematic (goes to pins 2 and 7 on tube sockets).

[Cygnus X1]

Hey Cygnus. Do you mean the pins on the tube itself? I don't see how I can do that with the tube installed (mounts flush in socket). I can either pull the tube and probe into the socket holes. Or I can see plainly the bottom solders of the tube sockets and the 2 junction things with 13 pins each (where they pin through the board). I can check there without taking anything else apart. Will that tell you what you're looking for? I can do that when I get home.

Is the "heaters" the "filament" on the tube board schematic (goes to pins 2 and 7 on tube sockets).

I have to run (work).
Yes, filament = heaters.
You can do it from the top with the tubes out.
Remember to count COUNTERclockwise from the tab for pin 2, then pin 7.
We are not measuring to ground, we are measuring between those two pins on the 6L6.

I said what you are looking for: 6.3 volts.

No heater means the tubes will not work.
Just a hunch.

[warlok]

OK. I'll try it when I get home.

[warlok]

There is continuity between pins 2-7 but no voltage. I also checked the 2 yellow wires from the power transformer where they go into the board at "filament" (J30 and J28 in the schematic) and there's no voltage there. On the tube board schematic, the 2 junctions (13 pin things), here's whats there: pin 9 of bottom one=463v, all 4 OP xformer pins=463, pins 3-4 on top (signal input) = -38v, nothing at any other pin (cathode returns or filaments). What do you think? Power transformer?

There's also a yellow wire from the OP xformer that goes to J50 on the board (between the green and black wires from the xformer) that has nothing, don't know what it does.

[warlok]

I looked at a marshall output transformer and it has all the same wires as mine and looks like the yellow one is for the cab impedence switch.

Would you assume/confirm that if the 2 yellow wires from the power transformer for the filament have no voltage, that's the problem and I need a new power transformer? Would that have anything to do with voltage going in but nothing coming out of the output transformer? Or is that a separate problem?

[Cygnus X1]

There is continuity between pins 2-7 but no voltage. I also checked the 2 yellow wires from the power transformer where they go into the board at "filament" (J30 and J28 in the schematic) and there's no voltage there.

What do you think? Power transformer?

There's also a yellow wire from the OP xformer that goes to J50 on the board (between the green and black wires from the xformer) that has nothing, don't know what it does.

Not sure about J50 right now.

First I'd replace that F6 slo-blo fuse.

Then if that makes no difference the I would disconnect the
two yellow wires and the green center tap & quickly check for voltage. Clip to green, and one of the yellows, check for AC voltage.
Then again green to the other yellow.

No voltage there means there's something wrong with the PT. (Open winding).
If there is voltage there then there's another problem downstream.
You should be getting 3 volts a.c. yellow to green.

HTH.

[warlok]

It's fixed!!!

I don't have the slightest clue what the fuck just happened. I pulled the yellows for the filaments and the green tap (J51) and checked for voltage. Got some weird reading (found soon after the meter was on the wrong setting), so turned the power off and for whatever reason, checked voltage at B+ and there was voltage that was was draining down. That never happened so I figured what the hell. Hooked the wires back up, turned on the power, and everything was lit. Plugged in the Dinky and low and behold the sweet sound of metal!!!! So I did what any smart guy would do, I grabbed a stick and poked at it... lol. I poked and prodded at anything I could reach to see if anything would stop it from working but it didn't even hiccup. Put it all back together, rocked out for 15 minutes, all still good.:ROTF:

I don't know what fixed it so I may just be waiting for it to happen again, but I can't find anything wrong now. I'll push it more later but all is good right now. So I'll just be happy with the $0.00 fix and hope for the best... Thanks again to all who helped. Especially Cygnus. I really, really appreciate it!!!

[jdr94]

hellz yeah!! thats what i'm talkin bout. glad you got it back in action!!

[warlok]

Kinda stupid but with all the work and frustration the last few days, I feel like a kid with a new toy and got permagrin!! WooHoo!!