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

Fairbanks Morse Model 8a Problem
#4

Thanks for responding Ron.... I have 300v at the plate of the 6k7 located by the 5y3 and 6v6 tube.  The 6k7 on the other side of the chassis has 300v at the plate when the band selector switch is moved to either of the short wave
bands.  I have voltage going to the rf coil, the antenna coil only seems to have heater voltage going to it or I should say the broadcast band of the selector only has heater voltage for the dial lamps. (I don't mind telling you I'm still not the greatest reading schematics so some things slip by me)  Pin 4 of the 6k7's in turn
have 150v instead of 105v.  I did a simple continuity check on the rf coil and every lug had a partner. Ran out of time and did not do the antenna coil. Is that the only test I can do? I did not see where the antenna coil would have any other voltage going to it unless I'm missing something in the selector switch itself. (Both trimmer coils (screws #1,2,3,4,) are good cleaned and working) 

Thanks for the advice on the antenna lug.....I had it where the schematic showed and picked up nothing. I removed it from that 6k7 plate terminal on the band selector and have it on the middle rod going from the selector center gang to the center band switch for now (must be 1st shortwave?) Guess that could be 1st indication of an antenna coil issue?
    
Bob

      


Messages In This Thread
Fairbanks Morse Model 8a Problem - by bm071 - 01-15-2016, 09:23 AM
RE: Fairbanks Morse Model 8a Problem - by bm071 - 01-18-2016, 09:24 AM
RE: Fairbanks Morse Model 8a Problem - by bm071 - 01-18-2016, 09:40 AM
RE: Fairbanks Morse Model 8a Problem - by bm071 - 01-18-2016, 07:37 PM
RE: Fairbanks Morse Model 8a Problem - by bm071 - 01-20-2016, 09:19 AM
RE: Fairbanks Morse Model 8a Problem - by bm071 - 01-20-2016, 05:55 PM
RE: Fairbanks Morse Model 8a Problem - by bm071 - 01-20-2016, 05:59 PM



Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
Jackson 715 not working
Now that you posted the schematic, I don't know why that Sprague electrolytic cap is across the meter, as it is not indi...MrFixr55 — 05:51 PM
HiFi (Chifi) tube amp build - but my own design.
What may be lacking in the PP Tube amps may be the 2nd harmonics, which some, especially RCA back in the day called &quo...MrFixr55 — 05:32 PM
Jackson 715 not working
Usually in an emission tester, the tube under test is measured as if it were a diode. So, some testers connect all the g...RodB — 04:17 PM
Restoring Philco 37-604C
Yep. F5 is green, D5 is Red. Red is Bad. Green is Clean.morzh — 01:30 PM
Jackson 715 not working
I did start to do that but I stalled out because I could not figure out how the grid and plate get voltage. In this diag...daveone23 — 11:52 AM
Restoring Philco 37-604C
(Insert Homer Simpson "DOPF" Here.) When all fails, look at the can. Took the Ron Ramirez advice, red Caig D...MrFixr55 — 09:23 AM
Philco 91 Speaker Replacement
From your text I am not sure if you intend to use the existing speaker with a resistor instead of the field coil. It wo...morzh — 08:44 AM
Philco 91 Speaker Replacement
My field coil is bad. I am still hoping to find an original, but if I can't I will go with a fitting Philco speaker, 125...dconant — 08:34 AM
Philco 91 Speaker Replacement
As Rod said, it is OK to use a fitting speaker, and then look for an original one. If you buy a Hammond 125 output tr...morzh — 08:15 AM
Philco 91 Speaker Replacement
Yes, I often have to substitute, then keep an eye out for an original. In the meantime, the radio is working and being e...RodB — 08:02 AM

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

>