Need Help With Maggie 64-03-00 Tuner/Preamp...

[racfan9]

Hello Everyone,

Do all the tubes in this tuner need to be installed in order to test for sound through the Aux inputs? I've got the 6eu7's in it but still getting no sound. One other question shouldn't the 3 dial lamps work also without the tubes?

Thanks,
racfan9

 

[RWood]

Hey, Terry, I'm not familiar with that chassis offhand, but I believe you are correct that the 6EU7 tubes are for the preamp and so a non-radio input should work. Tuner tubes need not be present as this is not a series-string circuit as far as I know.

The dial lamps work by having their socket mounts grounded to the chassis. So first check that they are. If not the bulbs could be bad, get new #47 bulbs. OR since they run off the same filament circuit that powers the tuner and preamp tubes it could mean that you have no filament voltage.

The filament voltage comes through the umbilical from the power amp, as does the power switch wires and the B+. All of these functions and voltages etc can be tested by measuring the pin voltages on those 6EU7s. If you are comfortable doing that safely, report back here what you find for al, of the pins. The quick test would be to check for cathode voltages - if there is a few volts DC there then the tube is conducting and filament and B+ must be present. Pins 4 and 9.