I have begun to restore a 37-630 which someone previously "worked on". They did a very amateurish job of trying to restore it, and I am having to undo all their mischief before I can properly restore the radio. If anybody has any good photos of the underside of the chassis of a 37-630 that has not been molested at all, in its virgin state before any restoration, and could forward them to me I would appreciate it. It will be of great help in properly restoring this radio.Thanks.
Note ! My 37-630 is a code 126 with the rectifier tube on the chassis, not on the transformer. Pictures of this version would be ideal, but either would be appreciated.
Well, I have begun to work on my 37-630. I have rebuilt the input condenser block and re-installed it. I have removed the two electrolytic cans on the chassis and will rebuild them this week. One problem I discovered was that the person who previously worked on it installed part #62 with the negative to ground rather than properly, with the negative to the transformer CT and the positive to raw B+ (see this link for that part of the schematic:
http://pagandad.tumblr.com/image/174532833199 ) Maybe that was why they gave up on it. Too bad they couldn't read a schematic, or even notice the insulation around the bottom of the can, and the little tab with the wire connected to it that went to the negative side of the condenser. Oh well, their loss is my gain. Maybe that's why I got it so cheap. I have been busy ordering those parts I don't already have in my inventory, mostly odd power resistors, 3 watt and 5 watt, to replace some in the B+ supply to various places that were 2 watt and 3 watt. I prefer to upgrade, and today's parts are smaller in the same rating, so they fit fine.
I also ordered a new dial from Radio Daze. Mine was faded and dirty, but would have been usable if cleaned, but when I went to clean it, using only water and mild dish soap, the lettering washed right off. So if you have an old dirty dial, DON'T TRY TO WASH IT ! You may come to the same grief.
So now I will wait for the arrival of some parts, and rebuild the electrolytic condensers. Rome wasn't built in a day, neither are old radios restored in one.
Mike
I merged your two threads on this subject to keep it all together.
Work continues on my 37-630. I have finished replacing what were the paper condensers before someone else worked on it. I have removed and rebuilt the electrolytic condensers, removed the electrolytic condensers installed by the mischief maker, and re-installed the rebuilt originals, and wired them into the circuit. I also replaced most of the resistors with new ones of the same resistance and higher wattage rating, although none of the originals were out of tolerance. I am currently waiting for my new dial and some #44 lamp bulbs for the dial and shadow meter, then I will re-connect the speaker, and see what happens. Hopefully, at that point, all I will have to do is an alignment, then re-install the speaker and chassis in the case.
I finished the actual chassis work on this radio early in the summer, but them took a break from it. All that was left was re-installing the tubes and alignment. I picked it up again about three weeks ago. Then I discovered that my frequency counter and my signal generator, both modern, made in China, were not working! Something must have happened to them in the move from RI to TN. I looked on sBay and found an old Heathkit signal generator, and ordered it. I am using a really nice digital readout shortwave radio to check its frequency output against. When it arrived, the very first thing I did was replace the power supply filter caps. It works very well, and its output is right on with the dial scale. I use the modern radio to make sure I am right on frequency. To set the IF, 470 KC, I tuned the radio to 940KC on the AM band, and then set the output of the signal generator to give me the maximum output there, I used the harmonic of the 470 output to double check it, in other words. After that, I could use the actual frequencies to check the output was right on. I have finally gotten the radio all working. The shadow meter does not deflect much though. I have tried everything. I used the shadow meter setup described on this site. I get deflection of the vane inside, it's not stuck. I can see the shadow move a lot when the set goes from off and warms up, but it only moves a tiny bit when tuning. The resistance on it is about 1500 ohms. I'm not going to worry much about it though, since other than that the set is working pretty well.