01-03-2020, 03:07 AM
Quote:This is where a decent digital camera comes in handy. I take pictures of the underside of the chassis as close as I can and still get a sharp focus. This is a great help to remember what is connected where. I de-solder everything connected to any condenser blocks and make a careful drawing showing what goes where. I then remove the condenser block entirely. I place it with the filling side down on a little tray made from aluminum foil, and put it in a low oven, about 250F. I let it sit there for about a half hour. This melts out all the black goo. I remove it, and then pull out the old guts with a pair of needle nose pliers. Once they are out, it is just a matter of replacing them with new ones. The new yellow poly caps are a lot smaller than the old paper ones, so this is no problem. I fill the extra space with crumpled plastic wrap, and top it off with a piece of paper and then black RTV. If the radio has condenser blocks I just rebuild them all this way. No point in doing one, and then hoping the others don't soon fail.
Mike, I was able to get the majority of the bakelite blocks rebuilt with them still wired into the radio, there was only 2 of them that I had to remove a couple of wire leads from to get the bakelite blocks out of the chassis enough to remove the guts but thankfully they were easy enough to remember where the wires went to because the were all on one side of the blocks.
And the radio is definitely performing much better now than it did when I first got it (I even did an IF and RF alignment by ear and the radio perked up even more, surprisingly enough the IF and RF alignment wasn't very far off.)
Anyways the radio is almost ready to go back together (minus refrinishing the cabinet).
I also figured out that almost all of this radio's broadcast spectrum is still in use to this day the lower quarter of the old Police Band on this radio is actually the rest of the AM band (the AM band on this radio only goes from 540 KC-1500 KC) and the modern AM Band goes clear up to 1720 KHz (which on this radio is the lower quarter of the Police Band on this radio which is 1.5 MC-1.72 MC or 1500 KC to 1720 KC) after that the rest of the old Police Band on this radio falls under the current SW I Band and then the current SW II band is the Night Time SW Band on here, and then the current SW III band is the Day Time SW Band on here, and then the Long Wave Band on here as far as I know does have some use in Modern times, but I wasn't able to pick anything up on it around where I live anyways.
Just some interesting stuff I found out about this radio while monkeying with it today.
Also as for the shadow meter on my radio, it does work but just barely, and I took some measurements of the resistor that is inline with the shadow meter and that resistor is a 1,000 Ohm resistor and it isn't very far off, as it measures around 860 Ohms (it drifted, but down, rather than up) which is still within tolerance, and the shadow meter coil measures around 940 Ohms which is around what its supposed to measure, its not open in other words. So, I'm not sure what's going on with the shadow meter and why it barely moves when tuning in a station.
And then there's a paper cap that is tied into one of the wafers on the band switch on one side and then the other side is grounded to the grounding braid that is attached to one of the screws that holds the tuning capacitor to the chassis, and I can't figure out how to get that capacitor out and swapped out for a new one because its in such an awkward spot to get into that I can't even get to it with my pliers to remove it, any ideas of how to go about removing that capacitor? In case you're wondering its #23 on the parts diagram in the Rider's which is a .05 MFD Tubular Capacitor.