Posts: 451
Threads: 85
Joined: Nov 2011
City: Cumming, GA
Looking for help . I have a philco 37-84 code 121. the only info I can find is for a code 122. I have 4 tubes 80, 42, 77, 77. is the wiring and components under the chassis the same only the tubes are different? The Radio Museum has some info but no prints.
The caps have been changed(kinda messey the way they did it), The radio powers up and hums with 2 spots on the dial having a squeal. Any help much appreciated.
Eric
Posts: 13,776
Threads: 580
Joined: Sep 2005
City: Ferdinand
State, Province, Country: Indiana
Use the schematic for Model 84. Although, the only difference between a model 84 (also 37-84 Code 121) and model 37-84 Code 122 are the tubes used. The 37-84 Code 122 uses octals, while the older 84 used the equivalent standard base tubes.
77 = 6J7G
42 = 6F6G
80 = 5Y4G
And please note when I use the equal sign, I mean electrically identical. Of course the bases are different.
Only recently did I become aware of a 37-84 "Code 121," and I see I need to make some changes in my site's Gallery as a result.
--
Ron Ramirez
Ferdinand IN
Posts: 451
Threads: 85
Joined: Nov 2011
City: Cumming, GA
Thanks Ron
Just started this got it at a garage sale, now I'm a novice but the under side of the chassis is a real butcher job, I started replacing the dog bone resisters and found 2 that were double in value and 2 more by 50%. The caps have been replaced by somebody and I will start checking to see that there correct. The 77 det-osc seems to be very sensitive.
Eric
Posts: 7,283
Threads: 268
Joined: Dec 2009
City: Roslyn Pa
Search this phourm for model 84. More than likely the antenna and osc coil are bad. The phourm has the info how to repair them. You will find that just about all of the resistors are out of spec so replace them. On these sets it is important to use a signal generator to align the IF. Some try to do it by ear but that is a bad move!!
Terry
Posts: 451
Threads: 85
Joined: Nov 2011
City: Cumming, GA
Latest update got the radio up and running turns out one of the Black Bakelite Condensers (#28 2-.015) was leaking pretty bad (the others had been bypassed) and I guess was passing thru a large AC component (loud humming) as one leg of 115 was tied in. That's were I got my handy chart from this site matched up the #'s and read how to remove the old wax and re stuffed with new caps.
I still have a lot of cosmetic work on the underside can't stand the haphazard way they did it. and the resistance on the Vol is twice the 20k ( reads 40k) it shows on the print but it seems to play fine. Thanks again to this site
Eric
Posts: 7,283
Threads: 268
Joined: Dec 2009
City: Roslyn Pa
Tnx for the update! Glad you got up and running.
Terry
Posts: 201
Threads: 26
Joined: Dec 2005
City: Morris Plains, NJ
There's a little brown hexagonal adjustment on the back of the chassis; this is the feedback adjustment and it sounds like that's what you need to tweak.
The 37-84 was my first old radio and cost me $1.25 at a junk store in 1956. I recall adjusting that feedback every day depending on station signal strength. At some point in my inexperience days I washed the dial clean with soap and water and then ruined the photofinish when cleaning it probably with wood alcohol. A couple of years ago I bought a replacement 37-84, one in absolutely showroom condition- and I still adjust the little hex feedback "knob".
Pete AI2V
Pete AI2V
Posts: 451
Threads: 85
Joined: Nov 2011
City: Cumming, GA
Yes you are right about that adj on the back but the radio looks good
Eric
Posts: 5
Threads: 1
Joined: Aug 2016
City: georgetown, TX
(05-30-2012, 03:40 PM)Ron Ramirez Wrote: Use the schematic for Model 84. Although, the only difference between a model 84 (also 37-84 Code 121) and model 37-84 Code 122 are the tubes used. The 37-84 Code 122 uses octals, while the older 84 used the equivalent standard base tubes.
77 = 6J7G
42 = 6F6G
80 = 5Y4G
And please note when I use the equal sign, I mean electrically identical. Of course the bases are different.
Only recently did I become aware of a 37-84 "Code 121," and I see I need to make some changes in my site's Gallery as a result. Ron
A 84B type cabinet uses the old tubes 77,42,80 (code 121) but I recently had two 84B type cabinets for epair using
chassis code 122 octal tubes. I checked your gallery and radiomusuem. It appears that 84B type cabinets used only
code 121 old tubes. Is that correct?
ABV
Posts: 13,776
Threads: 580
Joined: Sep 2005
City: Ferdinand
State, Province, Country: Indiana
Correct, model 84 sets only used standard based tubes. If you have a set with an 84 cabinet (1934-1936) and that uses octal tubes, then someone mixed 37-84 chassis and 84 cabinets at some time.
--
Ron Ramirez
Ferdinand IN
Posts: 5
Threads: 1
Joined: Aug 2016
City: georgetown, TX
(08-24-2016, 07:12 PM)Ron Ramirez Wrote: Correct, model 84 sets only used standard based tubes. If you have a set with an 84 cabinet (1934-1936) and that uses octal tubes, then someone mixed 37-84 chassis and 84 cabinets at some time.
Ron
Thank you for your quick reply. I need to inform the customers of this issue.
ABV
Users browsing this thread: 1 Guest(s)
|
Recent Posts
|
Jackson 715 not working
|
Mrfixr55, its working now. I cleaned the switches and sockets with spray cleaner. Thanks for helping on this one.daveone23 — 06:26 PM |
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 |
Who's Online
|
There are currently 3850 online users. [Complete List] » 1 Member(s) | 3849 Guest(s)
|
|
|
|