Welcome Guest! Be sure you know and follow the Phorum Rules before posting. Thank you and Enjoy! (January 12) x

Thread Closed
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:
[-]
Recent Posts
Philco Model 16 wiring question
Thanks Morzh. So it appears I did wire it incorrectly and I have to switch the wires between pins 2 and 4.bobclausen — 09:24 AM
Philco 46-1209 strange behavior
No, it's not a problem, just during certain condition it could show up. Yes, an internal tube short could do that too. ...morzh — 09:13 AM
HiFi (Chifi) tube amp build - but my own design.
You sound guys are never satisfied. :crazy: :clap:RodB — 09:10 AM
HiFi (Chifi) tube amp build - but my own design.
I got some new ceramic octal tube sockets installed and also tried some different coupling caps.  The results:  The go...TV MAN — 08:42 AM
Philco 46-1209 strange behavior
I pulled the tube out and it's shorted from pin 1 to pin 2. I suppose that's the problem...sq65 — 08:12 AM
1949 Motorola 5A9M
bob  Nice work on battery . If you don't. Have terminals i have a few spares  Samsam — 02:12 AM
1949 Motorola 5A9M
hello mr Fixr, for sure !! I have some radios that I need to make some batteries for too. Sincerely richardradiorich — 12:33 AM
1949 Motorola 5A9M
Dittos, sweet b on the battery. Love the "9 Lives" logo, remembered from my childhood. Other neat ones are t...MrFixr55 — 11:24 PM
Philco 46-1209 strange behavior
Hi Morzh, Dunno if the AC EMI caps are an issue. I never liked the concept but never had an issue with these causin...MrFixr55 — 11:21 PM
Philco 46-1209 strange behavior
And no hum without the 7AF7? Not common but I am thinking heater - cathode short. This would introduce hum in this sta...MrFixr55 — 11:14 PM

[-]
Who's Online
There are currently 1287 online users. [Complete List]
» 1 Member(s) | 1286 Guest(s)
Avatar

>