02-25-2009, 08:06 AM
I'm repairing 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 a bad hum) and it worked for a couple of more years. By following articles in your excellent web site, I have replaced all the 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. I got a schematic for this set from Chuck Schwark, Grommets from Ed Schutz, and a new Dial from Mark Oppat. Thanks 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. Doing voltage checks, I find that with the 100 watt bulb in-line I have 97 volts AC being applied to the radio input. With this low line voltage, all my plate voltages that should be 240+, are around 110V, and my 150V are around 80V. Are these voltages ballpark under 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 the plate and cathode (grounded cathode) and using the 0-30 volt range. Does anyone know what this meter was. I have 240v on this plate to ground. Whats with the 0-30v 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 if electronic circuits I haven't thought of or even heard about in many years. Mike
Second question, according to the alignment instructions, they use a Philco Model 025 Circuit tester, and connecting it between the plate and cathode (grounded cathode) and using the 0-30 volt range. Does anyone know what this meter was. I have 240v on this plate to ground. Whats with the 0-30v 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 if electronic circuits I haven't thought of or even heard about in many years. Mike