Here's a Newcomb EDT-15C solid state classroom record player from 1970 that I just obtained. I've cleaned and lubricated the drive mechanism and I'll soon address the cartridge and amplifier problems. The 89T cartridge is shot and the holder is damaged; so, I'd be looking at around $30 to get a sapphire tipped LP/78 cartridge and a holder. Lately, I've noticed 89T's are getting expensive and Gary no longer has the diamond LP/sapphire 78 version. So, I'm thinking of replacing the whole thing with a Pfanstiehl P228 cartridge and I'll probably have to modify the input circuit, since the P228 is not as hot as the 89T. It's now being said that the current P132, P226, and P228 are all the same cartridge and put out .5V Vs. the 1.3V of an 89T. I'll do some experimenting to see what works best. In another thread, someone mentioned removing the .001 uf input capacitor are adding a resistor in series with the capacitor. I like the idea of using a P228 cartridge because it is a true stereo cartridge and I won't be forced into replacing the whole cartridge when the needle becomes worn.
There is also a fairly loud waterfall sound coming from the speaker that is especially noticeable when no record is playing or during soft passages. I suspect this is due to a noisy transistor (probably germanium, I haven't checked yet). I'm sure my friend the oscilloscope will come in handy for this one.
