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

Philco 71b Filter Condenser Bank Question
#6

Also am yet again puzzled, and still a novice at radio restoration and troubleshooting. I tested all the tubes, this model uses a 42 for audio output, the st type already in the chassis tested bad and quite weak. I only have several Globe type 42's in my stock. It tested good, and I will use it as a replacement for the initial power-up. I first put the set in series with a dim bulb tester just to see if the transformer has any shorts and it didn't as I expected. I did tune the dial to see if I would get anything but didn't, most likely because of the voltage limiter caused by the bulb. I then did a slow power-up with the power cord plugged into a variac. The end result was; all tubes had a glow, there was also a 60 cycle hum heard when I increased the volume pot, it went away when the volume was at zero.

The most concerning thing is that I did not get any other type of noise out the set for those 3 minutes. I am hoping that a full recap of the electrolytics and caps will fix the problem, this is my first encounter with no noise from the speaker on an initial power up.

I also noticed the mica trimmers that come off each section of the three gang available capacitor are still present, but the second one is chipped a bit and the third one is bent up on one side as in the picture. I know there could be quite a few factors contributing but, could this of caused the silence in the set?


Attached Files Image(s)
   


Messages In This Thread
RE: Philco 71b Filter Condenser Bank Question - by Philco281989 - 05-02-2013, 09:09 PM
Help on checking the coils - by Philco281989 - 05-03-2013, 07:04 PM



Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
Philco 42-345 Restoration/Repair
RodB :beerchug:Vlad95 — 10:22 AM
Philco 42-345 Restoration/Repair
Vlad, you nailed it. Swiss and German roots.RodB — 09:54 AM
5U4 vs 5Z4 tubes
Well this is a Hallicrafters SX/9 circa 1936. No real issues so far although I dodged a real bullet with a cap that was...bridkarl — 07:59 AM
5U4 vs 5Z4 tubes
The pinout is the same but the 5U4 has a 3 amp filament, verses 2 amps or less on the 5Z4. I think that the pinout of a ...Arran — 12:04 AM
Philco 42-345 Restoration/Repair
By the way. osanders0311 Take a look here: Dial cord stringing Guides May be here you can fount correct string settin...Vlad95 — 11:15 PM
5U4 vs 5Z4 tubes
5U4 and 5Z4 almost identical. I think nothing happened if you left 5U4 instedad 5Z4 long time. Just heater current 5U4 ...Vlad95 — 11:02 PM
Philco 42-345 Restoration/Repair
Hello Vlad95 , Very Funny ! Sincerely Richardradiorich — 11:01 PM
Philco 42-345 Restoration/Repair
RodB You are European yourself   :evil: I'm Canadian for the last 30 years  :snowman: But not Yankee  :lol: Vlad95 — 10:49 PM
Philco 42-345 Restoration/Repair
The band switch selects different oscillator coils for the band selected. I would look for a bad connection in the switc...RodB — 10:31 PM
Philco 42-345 Restoration/Repair
Hang in there...PaulPaul Philco322 — 09:30 PM

[-]
Who's Online
There are currently 1000 online users. [Complete List]
» 1 Member(s) | 999 Guest(s)
Avatar

>