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

41-287 No voltage from secondary of transformer
#1

Hello, After wiring in a electrolitic capacitor the wrong way I fried the strip resistor (labled 61 on schematic) so I corrected the mistake with another new ecap and replaced all three of the resistors with 100w ceramics.
the damage also included the 84 rectifier tube which I also replaced. Now all I get is filament voltage out of the recitifer curciut. The transformer is not burnt nor is it leaking. The resistors I refered to replaced the 146, 31 and 15 ohms labeled 61 with part # 33-3393 . I hope this is enough information for you. Thanks in advance for any help. JEP
#2

Hello and welcome.

What kind of voltage do you get when you measure from plate to plate of the 84 rectifier tube? (Tip: Measure this as AC volts, not DC volts.)

If you are not getting anything here, chances are the power transformer is dead even though it did not smoke or leak wax.

Be careful! That AC voltage will be around 525 volts if the transformer is working!

Also, how did you replace the Candohm resistor? With individual resistors? Did you remove the old Candohm (multi-section resistor) from the circuit entirely?

--
Ron Ramirez
Ferdinand IN
#3

Hello Ron, Thanks for the fast response. To answer your question, I measure 532 vac across the plates of the 84 rectifier tube. The schematic shows 265 vdc across the 12uf ecap. Having replaced it with 22uf I show 360vdc and across the 16uf ecap the schematic indicates 180vdc. With the replacement 22uf ecap item 27A shows neg 56. Also you asked about the Candohm resistor, yes, I removed the entire piece and replaced it with separate 5 w ceramics of 15, 33 and 150 ohms. I also noticed an error when I changed the 12uf ecap - I had the negetive side to ground rather than the center tap of the transformer. So, no sound no smoke just filament and indicator lights. JEP




Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
Correct model 84 Ac plug an cord type
From what I read Philco went to using brown rubber power cords in 1936, so cloth was used in the 1935 and earlier models...Arran — 11:25 PM
Correct model 84 Ac plug an cord type
Hi Bruce, I have not worked on an 84, but in general, power cords for almost any radio prior to 1938 was cloth covered...MrFixr55 — 08:34 PM
Restoring Philco 38-14
OK, well, so after staring at the sch again, I realized the problem had to be the #12/12A padder. I put a scope on the o...morzh — 08:15 PM
Correct model 84 Ac plug an cord type
Hello Bruce, I mostly use brown far as my cloth powercords go ! Here is the plug that I have used bakelite Acorn style...radiorich — 08:05 PM
Correct model 84 Ac plug an cord type
Looking for as correct as can find the right Ac plug an the correct colored cloth line. Ive seen many old photos but mos...Bruce — 04:13 PM
Restoring Philco 38-14
Rod Two Y-caps make sense if you use them from L/N to the chassis; this is only makes sense in the transformer radios...morzh — 10:11 AM
Restoring Philco 38-14
Mike, I'm curious about a specific use of he Y cap. Lately I've seen a single cap across the power transformer primary. ...RodB — 09:01 AM
Restoring Philco 38-14
hello morzh , That sounds like a plan ! Sincerely Richardradiorich — 07:45 AM
Restoring Philco 38-14
Richard, It helped some, but I still had the whining when engaging the rear power strip (I did not realize it was fro...morzh — 07:07 AM
Restoring Philco 38-14
Hello morzh, Yes , that dreaded hum in my room where i do alighment I have my cable modem and router plus desktop plus ...radiorich — 11:25 PM

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

>