Did My Solenoid Fry in my RCA VDT-350?

[Doug]

the tape end lamp is in part of that circuit. its possible if its open the circuit will not turn on the solenoid which would protect the tape.
check that bulb.
doug

[Alex KL-1]

'bout the various transistors for solenoid: some group conducts first fro fast and strong mechanical magnetic force in the solenoid. Then, the others engage permanently with lower voltage. I see it in various cassete tape players and R2R, for not needing overdissipate the solenoit, since when it is already engaged, the needed force for maitain is much lower.

[TinCanAlley]

Originally Posted by Doug

the tape end lamp is in part of that circuit. its possible if its open the circuit will not turn on the solenoid which would protect the tape.
check that bulb.
doug

Bulb is working. I replaced that over a year ago and it is still working.

[TinCanAlley]

Well I believe I have found the culprit. I found a transistor in the transport circuit that is labeled as "Emitter Follower." It is 2SC1847Q NPN and when I test it, no matter what leg combination, I get no readings. I believe this to be the one that keeps the solenoid energized as it is the only one with a special heatsink that I believe is needed as it is energized during the entire play session and must get pretty hot.

As for the transistor, it isn't available anymore and NTE has a replacement (NTE373). I'm sure there are others that will work, but I don't know enough about comparing old to new to make a decision. If anyone with knowledge of better replacement choice wants to chime in, I'm open to getting the best replacement.

Thanks!

[redk9258]

Look at TTC004B. That looks to me like a good sub.

https://www.mouser.com/ProductDetail...eZ2DvzIw%3D%3D