Valvecaster problem - Could use some help

[BJM]

Hi everyone,

I could use some advice.... I've built a Valvecaster, 9 volt, original schematic and added a 7809 voltage regulator and a true bypass 3DPT switch with a led. I put the whole thing in a wooden box,  it worked o.k. but a little noisy/humming so I thought it would be better in a metal enclosure. I've desoldered most of it, put everyhting in an aluminium box and resoldered everything. And now it stopped working  .

No sound (of course) but what' s weird (at least for me, but I'm new to building this stuff) I can measure voltages, 12 volt from an old laptop adapter before the regulator, 8.8 after it and the led lights up when the switch is on. Only without the tube in its socket. With the tube in, no sound, the led doesn't light and the voltage after the regulator is 0.3 volt. Also the tube doesn't glow. I've checked the wires, everything looks o.k. Does this mean the tube's broken? Is it possible to test the tube? I don't have the stuff for that, only a multimeter so any advice is welcome

Thanks,

BJM

[GibsonGM]

It's hard to say, BJM, but sounds a lot like you have a short.  If it is simple to do, I would 'unhouse' the circuit, see if it works sitting on a table.   Maybe bypass the regulator, too...use a battery for a short test, if possible.   

Usually when you rehouse something, the errors come from breaking a wire, and something touching something else that it should not...a short somewhere WOULD dump your voltage down that low.  Tubes are pretty Tough!   I suspect a short.

You could try using your DMM, no power applied to circuit....check for continuity from regulator output to ground...one of a few tests you could make...

[BJM]

Thanks GibsonGM,

It's working again. I've also replaced the resistor for the Led with a higher value. Only thing is noise when turning the gain knob but I've read somewhere that's normal.

BRgds,

BJM