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

Philco turntable fries 7R7 tube in 47-1230
#1

I have completed full re-cap on a customers Philco 47-1230. I cleaned the Push Button section, and phono switch, & all is working great.
Today, after playing the radio over 20 hrs since restoration working great on all bands, something weird happened. I attached the phono a.c. plug 2-pin connector to see if phono motor would turn, and let the old phono motor run for a short amt of time. After some help by hand, the old motor started turning. In the process of doing that, the radio quit working. I had the old phono mono input rca attached, but the tonearm not connected thru the old hi-imp transformer mounted in fnt bottom of cabinet.
Anyways, the radio receiver shut down, but still had some audio on higher volume. After tapping on the tubes, I found the n.o.s. 7R7 tube I just purchased and played over 20 hrs testing from AES was very microphonic. I replaced the 7R7 tube, and the Radio receiver started working again.
My question is this, did the turntable motor pass some AC current via orig input wire back into the chassis to take out the nos 7R7 tube? Since I replaced the tube, everythings working fine in the radio again. I have unplugged the phono ac line output plug from chassis, and when I engage the phono pushbutton , everything is fine with just the phono RCA input still connected. Now I can engage & release the phono button without any harm to the radio. I really dont think the prob is in the phono ac switch. For now, I will leave the phono ac connector disconnected altogether. Without pulling out the schematic again, this doesnt compute for me right now? Anyone ever had this prob happen before? Thanks for your thoughts, Im overlooking something simple here on the Philco 47-1230 chassis. Randal


Messages In This Thread
Philco turntable fries 7R7 tube in 47-1230 - by Texasrocker - 01-20-2009, 02:36 AM
Re: Philco turntable fries 7R7 tube in 47-1230 - by Guest - 01-27-2010, 08:47 PM



Users browsing this thread: 4 Guest(s)
[-]
Recent Posts
12' Philco
And here's a story about the tires on the truck. Same "no-stoop" guy must have installed these! Take care a...GarySP — 01:17 PM
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

[-]
Who's Online
There are currently 5270 online users. [Complete List]
» 1 Member(s) | 5269 Guest(s)
Avatar

>