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39-30 Refurb
#14

Warren - That is a nice record to have!  i started getting into the big bands and early jazz once I started working on/collecting tube radios.  I wanted to hear what they would have sounded like playing the music from that era.  And suddenly i found my self enjoying it.  10 years ago i would have called myself crazy...

Terry - I replaced all resistors when I refurbed the radio.  R31 is reading 3.98M and R32 is 69.7k.  Both spot on.  I also replaced all mica's, so C34 is brand new.  I did check voltages way back when i first powered it on, but can't find the numbers.  But i do recall them all looking fairly good.  But I rechecked them.

Below is what I read, and in parentheses is what the schematic/service notes say (a few are hard to read, those have ? marks).  I had the variac on 115 to start, but it drifted down to 114 by the time I was done.  Radio was on BC and tuned to my SSTRAN (the service notes didn't say if it should be tuned to a station or not), but with the volume all the way down.  All readings VDC and to chassis, except where noted.

C43 - First filter
Pos to CT: 318.2 (325)
CT to Chassis: 14.88 (15)

C18 - Second filter
209.8 (215?)

C17
184.6 (190?)

84 Rectifier
Cathode: 303.9 (310)

6A8 Det/Osc
3 Plate: 209.8 (215)
4 Screen: 77.8 (80)
5 Osc Grid: -26.6 (n/a)
6 Osc Anode: 161.9 (175)

78 IF
2 Plate: 210.7 (215)
3 Screen: 78.0 (80)
4 Suppressor: -2.88 (n/a)


37 2nd Det/AVC
2 Plate: -5.11 (n/a)
3 Grid: -4.38 (n/a)

75 1st Audio
2 Plate: 143.1 (135?)
3 &4 Diodes (tied together): -5.69 (n/a)

41 Output
2 Plate: 203.8 (205)
3 Screen: 213.9 (215)
4 Grid: -14.02 (n/a)

Over all, nothing is jumping out at me as blatantly wrong.  B+ is a touch low - about 5 to 6v, but that shouldn't matter much.  The 75 plate is a little high, but I suspect that is because the DMM isn't loading the circuit.  The only other reading that is off is the osc. anode/"plate" that is about 13v low.


Messages In This Thread
39-30 Refurb - by Nick3092 - 05-13-2015, 10:32 PM
RE: 39-30 Refurb - by Radioroslyn - 05-14-2015, 06:25 AM
RE: 39-30 Refurb - by Nick3092 - 05-14-2015, 09:17 AM
RE: 39-30 Refurb - by morzh - 05-14-2015, 09:53 AM
RE: 39-30 Refurb - by Nick3092 - 05-14-2015, 10:56 AM
RE: 39-30 Refurb - by Nick3092 - 05-14-2015, 06:58 PM
RE: 39-30 Refurb - by Nick3092 - 05-14-2015, 10:58 PM
RE: 39-30 Refurb - by Nick3092 - 05-15-2015, 08:24 AM
RE: 39-30 Refurb - by morzh - 05-15-2015, 01:56 PM
RE: 39-30 Refurb - by Nick3092 - 05-24-2015, 09:33 PM
RE: 39-30 Refurb - by Nick3092 - 07-30-2015, 07:31 PM
RE: 39-30 Refurb - by Radioroslyn - 07-30-2015, 07:52 PM
RE: 39-30 Refurb - by Warren - 07-30-2015, 08:37 PM
RE: 39-30 Refurb - by Nick3092 - 07-31-2015, 08:19 PM



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