1. The PHILCO Phorum
  2. Philco Radio Discussions
  3. Philco Electronic Restoration
Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5

Threaded Mode
FM motorboating on Philco 48-482
Micro9
Junior Member
**
Posts: 36
Threads: 15
Joined: Aug 2007
City: Glendale,AZ
#1

11-01-2009, 10:34 PM
Need help on a Philco 48-482.BC and SW work great after recap but FM is very weak and motorboats when volum is rasied.FM was bad before I recapped it.All resistors are with in tolerance around the FM1000 and 7B6 tube.....Any ideas????
Find
Micro9
Junior Member
**
Posts: 36
Threads: 15
Joined: Aug 2007
City: Glendale,AZ
#2

11-02-2009, 11:53 PM
FIXED.....One of the "NEW" E-caps I put in went belly-up....Checked it before I put it in..It checked good...went belly-up after the power hit it.....
Find
exray
Phorum Expert
*****
Posts: 893
Threads: 9
Joined: Mar 2008
City: Vieques, PR USA State, Province, Country: PR
#3

11-03-2009, 09:00 AM
How did you pin it down? Did it swell up or pop?

-Bill
Website Find
Micro9
Junior Member
**
Posts: 36
Threads: 15
Joined: Aug 2007
City: Glendale,AZ
#4

11-03-2009, 02:34 PM
No I used my ESR meter and started from scratch again....Per the Schematic (I) part of the old Cap went to filter the FM.I cut the orginal cap out of the ckt before I put in a new cap in its place.....The cap looked just Like new but was shorted....
Find
codefox1
Silent Key
*****
Posts: 2,128
Threads: 18
Joined: Oct 2008
City: Merrick, Long Island, NY
#5

11-03-2009, 06:29 PM
Interesting. I have seen problems with motorboating caused by an open filter capacitor quite a few times, but a shorted one would either burn up the dividing resistor or cause the stages fed by it to cease functioning. Glad you got the set working again, but I'm afraid I missed something.
Find
Micro9
Junior Member
**
Posts: 36
Threads: 15
Joined: Aug 2007
City: Glendale,AZ
#6

11-03-2009, 09:13 PM
There was a 3300 ohm R404 that was also burnt. It wasn't open but was @3.5 meg and I replaced that also....
Find
« Next Oldest | Next Newest »




Users browsing this thread: 3 Guest(s)
[-]
Recent Posts
Hickok AC51 tube tester
I think they have only shown the secondaries of the transformer. Two of them feed the rectifiers' filaments.morzh — 12:58 PM
IF can wire size and Rubber mounts?
Arran If the wire inside cans is the gauges you mentioned, the sole reason for that would be mechanical, to stiffen t...morzh — 12:56 PM
12' Philco
Rod, Yes, I know, but the Giant Philco is not around anymore either, so I go by whoever was alive fairly recently. H...morzh — 12:54 PM
Hickok AC51 tube tester
Absolutely no one is going to reverse engineer that circuit. Even the iron core is missing.RodB — 10:37 AM
IF can wire size and Rubber mounts?
Thanks to both members for your help regarding wire and tuner mtg supports. regards--Johngeorgetownjohn — 09:33 AM
Hickok AC51 tube tester
Note that no power cord, power switch, or power transformer switch are shown. That (along with my experience with full s...DaleHCook — 07:09 AM
IF can wire size and Rubber mounts?
A pair of wire strippers can give you an idea of what the existing gauge of the wire leads are in the IF can, I think it...Arran — 06:07 AM
My last cabinet for this year
Hello Dan, That is really beautiful what great looking radio you have ! I have friends who live in Calgary and the wea...radiorich — 01:51 AM
Philco Predicta Siesta picture over time getting dimmer
I found that the wire insulation was burnt.  The fly back needs corona dope! Why would someone put that there?Platinumblonde36 — 01:09 AM
Philco Predicta Siesta picture over time getting dimmer
This is what it looked like beforePlatinumblonde36 — 01:01 AM

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

>
  1. The PHILCO Phorum
  2. Philco Radio Discussions
  3. Philco Electronic Restoration