[Guest]

I'm restoring a 37-620 that belonged to my father, but hasn't been turned on in over 40 years.I last repaired it in 63, (replaced electrolytic to get rid of bad hum) and it worked for a couple of years.By following articles in your excellent web site, I have replaced all paper caps and resisters that were out of range and replaced a defective on/off switch and an open output audio transformer and much degraded wiring.I was able to get the original parts from Gary at Playthings of the past, a schematic from Chuck Schwark, grommets from Ed Schutz, and a new dial from Mark Oppat. Thank you guys for a rapid response to my orders. I next built a dim light rig (also found on your site) for turn-up. Progressed from a 15 watt bulb to a 100 watt bulb and am now receiving a couple of local stations with the 100 watt bulb in line. During voltage checks, I find with the 100 watt bulb in line, I have 97 volts AC being applied to the radio in-put. With this low line voltage, all my plate voltages that should be 240+, are around 110V and my 150 volts are around 80 volts. Are these voltages ballpark with this set up? I want to go direct with out the in-line 100 watt bulb, but thought I would seek a little advice first.
Second question, according to the alignment instructions, they use a Philco Model 025 Circuit tester, and connecting it between plate and cathode (grounded cathode) and using the 0-30 volt range. Does anyone know what this meter was. I have 240 volts on this plate to ground according to the schematic. Whats with the 0-30volt range on the test meter. Thanks in advance for any response, also for this site. I enjoy reading the many great articles, they bring back many good memories and have me thinking of electronic circuits I haven't thought of or even heard about in many years. Mike

[AI2V]

I would go ahead and fire it up without the bulb; everything sounds OK so far. To be safe, keep your hand on the on/off switch just in case of smoke- a normal practice for a first firing-up.

It looks like an error in the meter range setting; it should be the 300v range. There's nothing special about the recommended Philco Model 025 meter other than the increased loading as compared to modern voltmeters. If you are using a modern digital voltmeter you should expect slightly higher voltages than with older meters.

Keep us informed on the progress or lack there of. The 37-620 is a great radio- mine is used several hours a day. Also, getting into the raised RF stage for component replacement is much simpler than it appears.

[Guest]

Thanks A12V Pete I plugged it in and it worked well. I do have a 5Y4G rect. that needs replacing, it seems to be a little weak. If I turn it on cold (not warmed up on the 100watt low input rig), it takes a while for the plate voltages to stabilize. I have a low hum in the back ground, not affected by volume control. Will have to run that down. I do have the hum coil connected in the speaker,so that is not the source. Since firing it up, I discovered that sometime in the past, it seems lightening might have hit near by. The antenna coil in the broadcast range, is missing the center tap and wire are missing. This is on the primary side. I haven't been able to locate one yet and it receives local stations well, so I'll use it while looking. It looks like that will be a problem to replace if I find one. What antenna do you use on your radios? I don't have room for a long wire, but have seen a couple of desk top type on line for use with SW and BC. Have you or anyone you know used such an antenna? Have a great day and thanks again for your help. Mike