HELP - TEAC A-500 Pause Solenoid Just Won't Stop Firing

[Pub Sub]

Hey all!

I have browsed this site for a while, but today is the day of my first post as I am in need of some assistance!

I have been trying to repair a TEAC A-500 cassette deck for a while now without success.

My issue is this:

The deck auto pauses like it's trying to make its own music! When the play mode is engaged, the solenoid that is in charge of pausing the tape movement fires and retracts in a vicious loop. It is usually of a consistent pace wherein it will fire then retract then fire again within 1 second. Sometime it deviates from this slightly, and sometimes it will pick up to a very quick cycle. If I start the machine with the timer auto start engaged, it will sometimes play for a good long while without any issue of auto pausing.

Things I have tried in my troubleshooting with limited knowledge:

• Check reed switch- The counter works and the reed switch works (tested with multimeter.)
• Replace belts - Belts have been replaced with appropriate new aftermarket belts offered by a reputable belt kit dealer.
• Cleaning - All rubber and plastic transport mechanical parts have been cleaned and appear to be operating as required when in the play mode. I have liberally sprayed contact cleaner on boards and connectors that I think come into play here.
• I have observed the voltage to the motor and it stays steady while in the play mode, whether the pause solenoid loop is in motion or not.
• The voltage to the pause solenoid is 37.8v when the play mode is not engaged and the machine is on, and it drops down to 33.2v when the play mode is engaged and it begins to play correctly. When the solenoid firing loop begins, the voltage drops down further and fluctuates between 27-29 volts quickly.

As stated, I don't really know what else to check and am hoping that someone can give some guidance. I have the service manual, schematic, and user manual, but I'm not knowledgeable enough to use the schematic to its full potential.

Thanks for any help you can offer.

 

[skywavebe]

Look at the solenoid drive as that is what is going wrong and then go back from there. Most likely a bad cap around a control section or a shorting transistor but the transistor would stay shorted so it sounds like bad cap- has the power supply been recapped yet. Someone in my past had this issue and I think he said he found a bad cap. I would have to see the unit to tell you further what it is.