Wanted Technics SH-400 CD-4 Demodulator Parts Unit

[BigAlt]

Looking for a Technics SH-400 CD-4 Demodulator Parts Unit. Need one of the Seperation Controls as I obtained a unit that has one of the Seperation Controls that is completely frozen and needs replacement. As might be expected Technics ( Panasonic ) has long discontinued this part.

 

[Doug G.]

There is almost always a way of getting "frozen" pots unfrozen. If it's the shaft, applying penetrant several times will usually free it up. In fact, the shaft is about the only thing that can "freeze" It's very unlikely the wiper would ever get stuck to the carbon track.

Doug

 

[BigAlt]

I've tried penetrant with no luck. I've also tried light tapping. This control should not only turn but also push in and out locking when in but still able to turn. It's stuck in the in position and won't turn or unlock. The shaft appears to be slightly bent.

 

[Doug G.]

Oh, you know what? I forgot about, if some parts of the pot are made of zinc alloy castings (Zamac), they can swell up and stick. If the body is made of this and the shaft passes through (are the shafts brass? I have an SH-400 but it's been a long time since I had it apart), the shaft could get stuck. I guess the only way to free it, then, would be to remove it, support it somehow, and tap the shaft out with force. Then you would have to redrill the hole and reinsert the shaft.

I can see, with these particular pots (pushing in and out), it may be difficult to do that without damage.

Doug

 

[BigAlt]

The pot and the assembly that locks the knob in the pushed in position are a complete assembly soldered to a circuit board. I can remove the assembly but I don't think that the pot is repairable. That's why I'm looking for a parts unit.
Al