Metropoulos Forum

My Metroamp JTM45 quit making sound after a couple years of sounding great.. I tried some new tubes and it still doesn't work.. I checked the resistance for the OT.. Red Wire is the C.T. Here is what I have found
Primary
Brown to Red Wire 129.8 Ohms
Blue to Red Wire 102.8 Ohms
Brown to Blue Wire 231 Ohms

Secondaries are all around 1.3 Ohms

I am thinking that the OT is shot Because of the different readings on the primary.. Any opinions would be very helpful.. Thanks

Have you tried changing the HT fuse? I've had them were they looked ok, but when replaced turned out to be bad. I only say this because sometimes we overlook the obvious. With a blown HT fuse, the amp will power up, but no sound.

Switched in a new fuse ,still nothing

It's not uncommon at all for one side of the primary to read a little higher than the other (I think the difference can actually tell you which side goes to which tube, but I can't remember which wasy was which right now....)

Voltages?

Remove power tubes.

Switch your standby switch to "play" mode.

Set your meter for AC volts and measure your PI output signal from ground to right where the PI coupling caps connect to the 220K "bias feed" resistors. Strum some chords...you should see about a 40-50VAC swing at both resistors. If you measure around this voltage, this rules out anything in the preamp. If not, then your issue lies somewhere in the preamp/phase inverter upstream of the power amp.

If you've ruled out the preamp, switch the amp off and measure resistance to ground at the speaker jack without the cab connected. If you measure an open circuit here, check continuity across the impedance selector switch (should read 0 resistance between the speaker jack tip connection and whichever terminal the switch is set to).

Well.. I feel kind of dumb.. It was tubes V1 socket.. Needed a good cleaning and retensioned.. Hey save me 125 bucks.. Thanks for the help everybody..