Crate Stealth 50

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Crate Stealth 50

Postby Blair » Mon Nov 05, 2007 9:29 am

Hey guys,

One of my friends dropped off a guitar head. A Crate Stealth 50 designed by Lee Jackson. It has no sound output, but the tubes are old. I cannot find a schematic for the life of me. It uses 3 X 12AU7s and 4 X 6V6s.

The main input is no functional at all, and when I hook up the aux input, I can hear the music a bit, but not through the speaeker, but the OPT. What would cause this? Anyone know a good source for the schematic for this amp?

Thanks,

Blair
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Postby EWBrown » Mon Nov 05, 2007 10:37 am

f you canhear sound emanating from the OPT, go no further, without connecting some kind of load to the OPT secondary. Otherwise the OPT can arc-over inside and short out.

I'd look for a blown "open" speaker, or a bad connection between the OPT secondary and the soeaker. Especially check the little flexible wires between the speaker's terminals and the voice coil, sometimes these get over-flexed or corroded, and go "open".

It's easy enough to check the speaker with an ohmmeter. It should have a low resistance, between 2 and 8 ohms DC.

/ed B in NH
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Postby Blair » Mon Nov 05, 2007 10:57 am

Thanks Ed, but I already ran a continuity test on the OPT, and the speakers are very good. I used them all weekend while cleaning out my garage.

Maybe there is something going wrong as you suggest with the speaker selector switch or something in the ouput path. I'll check it out.

Blair
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