Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5

37-10 plate voltages 100 vdc high
#16

Well, great suggestions so far, but DC voltages on a small set 100+ volts positive means either bad measuring equipment or real bad prior alterations. A schematic posted would be really helpful and a few snapshots would also help. So far, not enough to go on IMHO.
#17

this radio works but not properly. i have recapped it and changed resistors #80, # 83, # 86 and replaced cap #31 with 18 mfd.
I have checked most resistors and changed out those that were broken, burned or out of tolerance.

Ok i am starting over. ECG DM-38A Digital multimeter measured to chassis.

osc control tube 6N7G CALLS FOR 260 VDC ON P1 & P2. Actual is 184.5 and 3.3 on K.
6F6G OUTPUT CALLS FOR 250 0N P & 235 on S and 260 on S & 250 on P.
Actuals are 295 & 290 / and / 274 & 264.
6A8G calls for 250 & 85 & (150 0sc plate), actuals are 285.5 & 78,5 and (osc p 135.4)
6K7G (if) calls for P=260, S = 85, & neg 2.5 / actuals are P=295.6, S 79.4, & neg 2.7.
6K7G (rf) calls for 250 & 85 and actuals are 284.5 & 79.5 and neg 2.7
6Q7G calls for 170 and actual is 116.6 on P.

signal is weak unless i hook up 80' of antena and signal is distorted if i was working on a guitar amp i would say it sounds like the pre amp is over driving the output or the neg bias on the outputs is too low making the output fuzzy.
terry
#18

FYI I posted pictures to my dropbox account
CHECK AN EARLIER REPLY FOR THE DROPBOX INFO
#19

 Have you checked the tubes in a tube tester yet? High B+ voltages can be caused by weak tubes, particularly the power output tube.
Regards
Arran
#20

Those voltages are not really out of line. You must consider that the original voltages were taken on most likely a 5000 ohm/V meter. This will drag down the voltages quite a lot compared to a modern DMM with 1 Megohm/V.

I suggest that your poor reception problem may well be one or more of the antenna coils having an open secondary winding.




Users browsing this thread: 3 Guest(s)
[-]
Recent Posts
Philco 16B Parts
The 16B's in the tombstone cabinet sport a 10 1/2" spkr vs the older cathedral sets which uses an 8". The p/p ...Radioroslyn — 12:58 AM
Philco 38-7 Oscillation
I have let this one sit because of other duties. Now I am back, and I have a couple of questions. I hooked up a Hammond ...tludka — 11:16 PM
Philco 38-7 Speaker
I know that when I first started working on this radio, I did not even have a speaker. Once I finally found one it was n...tludka — 11:00 PM
Philco 60 Squealing
I seem to remember eliminating a squeal by changing the IF frequency by a few KHz. Not that you should put too much tru...fenbach — 08:48 PM
Philco 42-390, code 121 speaker
These speakers pop up on eBay regularly, even if at bloated prices. Honestly, have not seen many parts on swapmeets.morzh — 08:38 PM
Philco 38-7 Speaker
The put-put is not like the speaker problem.morzh — 08:29 PM
Mission Bell Model 19A Car Radio
Hello everyone,  As mentioned in my last post I was going to see if the vibrator / rectifier section could be persuaded...Antipodal — 08:21 PM
Philco 60 Squealing
Wondering if I did it backwards. If a coil was wound backwards, the oscillator would not work at all. Old school...Chas — 07:23 PM
Philco 38-7 Speaker
4-ohm speaker. Black, Green leads.tludka — 07:00 PM
Philco 42-390, code 121 speaker
#87 on the schematic.  This radio had a 8" Zenith  speaker attached to it when I got it. I do don't know the hist...Stevelog — 06:39 PM

[-]
Who's Online
There are currently no members online.

>