The Fisher Saga Continues - Act III -

 Been working on this post since right after Thanksgiving. I'm making very good progress on the Fisher, and will most likely power it up this weekend.

I have to admit that this receiver needed more work than I expected. It showed signs of being repaired at least twice before, and while the work was of acceptable quality, two of the transistors were a substitute type with different specs. Then I found the under-rated capacitors. A couple of them were open, ten or so were leaky, some showed signs of heat distress, and one appeared to have lost a very tiny amount of dielectric fluid.

Oh, and there were two resistors that had lost their smoke.

I managed to get the tuning mechanism back together, and restrung the dial cord. This had been hanging over my head since I started working on it. The service manual diagram didn't match what was in the receiver, so I used my "Before" photos to see how the gears on the main tuning capacitor fit together, along with a tabbed thrust washer, and how the dial cord was strung. This started when the shaft that goes into the main tuning capacitor came out in my hand and dropped two small parts out as I was trying to diagnose why the tuning was so sloppy. The OEM dial cord was stiff, dried out, and brittle. It made the tuning feel "gritty". AND the tuning mechanism is not documented, with the drawing in the Service Manual not matching how the receiver was built.

 

 

 And now that the front panel and knobs are cleaned and back on it, it's starting to look like a receiver again....

Among other non-documented changes were four capacitors on the Power Amp Board, along with two resistors and a capacitor attached to it, and two small inductors on the bottom of the Power Amp Board. Took a while to trace those parts out, figure out why there were there, and make notations on the schematic.

ALL of the electrolytic capacitors on the Power Supply, Power Amp, Preamp/Tone, Equalization and FM/MPX boards have been replaced. Eleven aluminum electrolytic capacitors in the FM Multiplex section were replaced with tantalum electrolytic capacitors for improved frequency response and stability, and six more on the Tone and EQ boards were changed for the same reasons.

These had failed and were very "leaky".

And while these still appeared to be OK, how many of them are on the edge of failure after 40-some years?

The gooey looking stuff on one end of the larger capacitors is NOT leaking electrolyte. It's a glue used in assembly to keep larger, heavier parts from coming loose before the board is soldered. It's also used in high-vibration environments to keep the parts moving around and cracking their soldered connections to the board.

ALL the wire wrap connections were inspected, and soldered. There were a half dozen that were coming unwrapped, and most of them showed signs of distress.

All the controls and switches were cleaned and lubed with DeoxIT D5 or Fader F5, as appropriate.

All panel lamps were replaced. Yes, I could have replaced them with LED's, but that would involve making a little Rectifier/Filter board as the lamps are fed with 8 Volts AC.

So stay tuned, kids for Act-IV..... The Power Amplifier Autopsy.....

I greatly appreciate my friend's patience and understanding in this. We never really discussed what "Fixing It" can entail. I sympathize with him, as I have numerous friends who had the I Went For A Brake Job, ANNND...experience.

Yes, there will be an Epilogue, probably called something like "Testing And Delivery"...