[Ron Ramirez]

Progress report:

I still have not ordered any parts. I was out of town all day yesterday, so nothing happened at the workbench yesterday.

This afternoon, I decided to see if I could get into the off-on switch to try shooting it with DeoxIT. I could not get the switch off the back of the dual volume control, so I drilled a tiny hole in the side of the switch and sprayed some DeoxIT in that way. It didn't help. So it looks like I will have to use a control from a junker set to get a working switch.

So...while the 700-T was on the bench, I removed the MPX board, decided that I could get a .047 uF, 630V metalized film cap to fit in part of the space formerly occupied by PC401. It fit by folding one of its leads over and installing it as a radial mount cap. I also installed individual resistors to replace the three that were built into PC401. I didn't have a 2.7K so I took a chance and used a 2.4K. Oh, and yes, I replaced C419 with a new 1 uF cap. I only had a regular electrolytic on hand so that is what I used. I'll replace it with a new mylar cap later.

I hooked up the speakers, plugged it in, and turned the thing on.

I now have a working MPX decoder!

Now, here's the odd thing about that LED light. Prior to trying it out today, I pulled the 390 ohm resistor out that I had in parallel with the LED, and temporarily installed a 1K as Mondial had suggested. Now, the LED gets bright on a stereo station, then dims when tuned off station...but remains lit dimly when off station. It also remains dimly lit when switched to PHONO, TAPE HEAD or AUX.

So I guess I'll have to go back to an incandescent bulb. Darn it. I really wanted to use an LED here, but it doesn't look like I can in this particular set.

The original was open, so I'll have to find a bulb. (Hmmm...I wonder if that 440-T junker has a good bulb?)