Phonoland

I have not been able to find any help in the troubleshooting guides for my current problem. Each time a record is mounted and begins to play there is no sound! I then have to turn the machine off while it is playing and a "pop sound" is heard from the amplifier. Then when I turn the mahine back on there is sound and the record plays with sound until the next record is mounted and begins to play, at which point there once again is no sound until I again shut the machine off wait for the "pop sound" from the amp and then turn the machine on again?

Any ideas how to resolve this problem will be appreciated.

Thank you
Darrell

Additional info, when I first selected records there was a "humming sound" coming from the area of the latch solonoid. After approximately 15 records had been selected (and the on/off routine had been followed to restore sound) the "humming sound" coming from the area of the latch solonoid disappeared and now the machine does not lose any sound when mounting a new selection?

Darrell,
Strange--the latch solenoid, is not connected in any way, to the sound system---least it should not be--
Next time you have no sound---sneak the rear door open carefully and look at the 5U4 tube--is it lit ?
Ron Rich

Darrell, I think you have two unrelated things going on.

The humming latchbar solenoid is fairly common in any AC relay or coil. It generally caused by loosening of the laminates in the core or loose coupling parts. Not serious, but the latchbar solenoid should -not- be left on continuously.

Since you lose sound in both channels, we must look for a common cause.

With machine playing but no sound:

First, try playing the machine with the mute plug removed to eliminate the mech's contacts are culprit.

Next, take your volt meter and measure the voltages on the filtering capacitor C120 A-B-C-D

Then look at C 121 and C122 these are the low Dc caps that power the preamp and bias the 6973 tubes. BTW: if the 6973's are glowing with red plates you have found the problem: bad rectifier or open resistor.

---Be careful when working on a hot chassis as there are lethal voltages. Use only one hand (to hold the probe) do not allow the other hand to touch anything on the machine.

Rob/NYC

Mark checked the 6973 tubes and found two of them to be defective. Replaced 6973 tubes and I have not had the problem again

Many thanks to all for their assistance.

Best
Darrell