Crate Vintage Club 60 PT

[Hicks86]

My buddy and I have had this Crate VT60 for a while and its just been sitting in our practice space for the whole time. His brother in law picked it up somewhere and then found out it has a bad transformer. I don't know where he got that info, but it seems to be a common problem for these. I've seen that you can get a replacement for around $200, but the amp is not worth that much to me. I'm just going to turn it into a cabinet if the $200 transformer is the only option. I just wanted to pop in here and see if anyone had any alternate thoughts or ideas on this. I've heard that sometimes its not the PT but some diodes, but I don't really know how to check that. Thanks!

[The Dude]

The first thing I'd do would be to test the transformer and verify that it is bad. You wouldn't want to spend $200 on something you don't need.

[Helmholtz]

Please find and post schematic.

[The Dude]

Here ya go.

VC60.pdf

[Enzo]

FIND OUT what is wrong with it, don't assume it is a transformer with zero evidence for that.

There are plenty of non-technical people out there who just assume any time an amp doesn't work, it must be a transformer. I think "transformer" is the only tech word they know.

[Helmholtz]

I miss the ground connection of the HV -CT.

[Hicks86]

I just brought it home late last night. Its been sitting in a corner for a few years. I haven't had a chance to test anything yet. Just going off what I was told so far. I'll check the transformer tonight.

[J M Fahey]

I miss the ground connection of the HV -CT.

You are right, but itīs a drawing error, it is certainly there and connected to power supply ground.

[Hicks86]

I took the amp apart last night and immediately saw that one of the 2 larger tube sockets had burn marks on it. I don't know what voltages I should be seeing on the power transformer to test for. I realized after taking it apart that I am an idiot and I didn't plug it in beforehand to see what it was doing. I had a long time ago but I can't remember what it did. Got trigger happy with my screwdriver I guess. I'm going to put it back together and see what it does if I plug it in and hook up a guitar to it. I don't know much at all about tubes and tube amps. If there is a burnt tube, will there be no sound or just bad sound?

[Helmholtz]

I assume you are familiar with high voltage safety precautions.

Pull power tubes, check for correct mains fuse and turn on. If it doesn't blow the fuse fuse, measure heater voltage between H1 and H2 (J32/J34).
Nominal value is 6.3VAC +/-5%.

[drewl]

Have one of these with the typical blown PT.

Replaced it with a generic Weber and for the low voltage I used a Fender Frontman 15 pt that was just right and fit nicely inside.

I'm not surprised the originals go bad, the low voltage circuit powering the DC filaments really sucks some current.

After about an hour or so the 12 volt regulators were crapping out, hot as hell.
They were 1 amp versions so I bumped them up to 1.5 amp ones I have.

I wonder if it would be better to use a couple 5 watt zeners like Fender does with the Hot Rod series.

Maybe a low current fan.

Maybe some thermal grease between the heat sinks.