Philco 37-690 Restoration - Printable Version
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Philco 37-690 Restoration - Kenradio - 05-11-2018
Good morning, got started last weekend on restoring my Philco 37-690. Both chassis have no rust and are in excellent physical condition--still trying to figure out what to use for the chassis shield that goes on the bottom of the receiver--I don't feel comfortable with the underside of the receiver being exposed. The dial is in very good shape other than a small crack between the start & end of the dial which isn't too bad--I would get a repro dial but the one Radio Daze has doesn't have the printing on it in the correct font and there is other inaccuracies. I'm starting on the receiver chassis then move on to the power unit. I plan to re-stuff the electrolytics and the 2 paper caps on the power unit but not stuff the paper caps on the receiver unit for now (I'll save the old caps to restuff later) I replaced 3 metal tubes and 3 missing tube shields already and fixed the magnetic tuning switch as it was intermittent and rebuilt all the lamps. I have 2/3 of the receiver re-capped and replaced 1 resistor in the RF unit. I will finish up on the receiver chassis tonight. Ken
RE: Philco 37-690 Restoration - Ron Ramirez - 05-11-2018
RE: Philco 37-690 Restoration - Kenradio - 05-12-2018
Good morning Ron, I started on the receiver chassis again early this morning and just about done recapping it as well as checking resistors to see if any need replaced. I cleaned & reassembled the automatic tuning assembly & the floodlights/main dial lamp. I replaced the 2 labels on the rear of the chassis also as the originals were deteriorated. I tested all 13 tubes earlier and all are good. I checked all coils in the RF unit when I had it disassembled last Saturday and all 15 coils including the Range 2 oscillator coil are good. I will start on the power unit tonight and restuff all bakelite block caps and restuff the 2 paper caps also and check the rest of the components on it. I have pictures attached to document my progress on the receiver chassis. Ken
RE: Philco 37-690 Restoration - morzh - 05-12-2018
Wait, Ken, Ron's out of pop-corn.
RE: Philco 37-690 Restoration - Kenradio - 05-13-2018
Good morning everyone, finally finished the receiver a little while ago and currently working on the power unit. I noticed in the fused power plug there is 20A fuses in it which are not the correct ones--does anyone know what the correct fuses are for the radio? Yesterday I removed the left high frequency speaker baffle to reattach the sagging grill cloth--used Elmer's Spray Adhesive which works very well and re-oriented the CB2 speakers so the terminal boards face up toward the top of the cabinet. I'm glad I don't have to refinish the cabinet as it is in excellent shape. Ken
RE: Philco 37-690 Restoration - Ron Ramirez - 05-13-2018
Man, you work fast!
The correct fuses are, I believe, 2A.
RE: Philco 37-690 Restoration - Kenradio - 05-13-2018
Hi Ron, thanks for the info on the fuses--much appreciated. I started last Saturday (5/5) with the restoration--I was up for 9 hours working on the receiver chassis going through every part of it--finally finished with it earlier this morning (another 6 hours) and now working on the power unit but taking a break for a few hours then back into it again. I bought 2 wirewound resistors on the auction site this morning to replace the 3000 & 2240 ohm candohm in the power unit as it is notorious for failing. I may be far enough to test it tomorrow to see if the radio works (cross my fingers). All the speakers are good as well as the cabinet not needing any work on it. I'll have more pics soon. Ken
RE: Philco 37-690 Restoration - GarySP - 05-13-2018
OK gurus, what was so different with this chassis that it required ALL the tubes to be in shields? Just curious. Take care, Gary
RE: Philco 37-690 Restoration - Phlogiston - 05-13-2018
They probably could have gotten away with just the RF and IF tubes in shields. Or with no tubes in shields if they were willing to put up with RF interference and or images and noise. These issues are usually not severe enough to limit broadcast band listening (but can be). But, if they wanted to pull SW out of the weeds, it was a good idea.
If you really want to prove this, try to do an alignment without the shields or just run the radio without the shields.
OH, the osc. tube really needs the shield too.
Better radios usually have better shielding.
RE: Philco 37-690 Restoration - Electrothaumaturgist - 05-13-2018
All 12 shields were present on the 38-1
Superb performers with them on!
RE: Philco 37-690 Restoration - Kenradio - 05-13-2018
I had to replace 3 metal tubes that were in my 37-690 when I got it--luckily I had some spare Philco tube shields to use. My Philco 38-1 has all of its tube shields also. Ken
RE: Philco 37-690 Restoration - Ron Ramirez - 05-13-2018
Ken, you are also lucky that Philco designed the 1937 tube shield bases the way that they did. Using the four crimped "fingers" to grip the tube shield, the base is made in such a manner that any type of tube may be plugged in - G, GT or metal.
Unfortunately the 1938 models use the same tube shield bases as did the 1936 Philcos. This means that only G tubes will fit in the tube shield bases. I can't tell you how many 1938 Philcos I've encountered with their tube shield bases either damaged or ripped completely out so that a metal or GT tube could be plugged into the socket.
RE: Philco 37-690 Restoration - Ron Ramirez - 05-13-2018
(05-13-2018, 09:44 AM)GarySP Wrote: ...what was so different with this chassis that it required ALL the tubes to be in shields?
Well, not all of the 37-690's tubes were shielded. Just all of the tubes in the tuner chassis, and (as I recall) one on the amp chassis. The audio output tubes, the two rectifiers, and two others on the amp chassis were not shielded.
RE: Philco 37-690 Restoration - Kenradio - 05-15-2018
Good morning, I took a vacation day off work today so I can do some more work on my 37-690. I got the power unit all recapped and decided to test it out and the radio works quite well other than a lot of crackling/popping noises in the audio which I suspect the large candohm being the culprit (I did order resistors to replace the 2240/3000 ohm sections)This radio is quite loud and the automatic bass control is working as well as the high frequency speakers. I checked the dial calibration according to the service bulletin and noticed all bands except for band 2 are slightly off but that shouldn't be an issue to realign the other 4 bands----band 2 dial accuracy is excellent. I tested the magnetic tuning operation and it works great. Hopefully when I replace the 2 resistors in the candohm unit the crackling will disappear. I'll have pics of the setup as soon as my cell phone is done charging. Ken
RE: Philco 37-690 Restoration - Kenradio - 05-15-2018
Good morning Ron, I know what you mean about the 1938 model tube shield bases being hacked up. I've had a few 1938 Philco models with the shields messed up and had to replace them--it was pretty clever of Philco designing the bases so RCA metal tubes couldn't be inserted in them. I'm curious, why did Philco use the enclosed bases in the 1936 models, use the open shield bases w/clips in 1937 then switch back to the enclosed bases in 1938? I thought maybe Philco noticed people using metal tubes as replacements in their sets. Ken