Welcome Guest! Be sure you know and follow the Phorum Rules before posting. Thank you and Enjoy! (January 12, 2025) x

Thread Closed

Philco 90 filament section on PT bad
#6

I had a bad heater winding in my HRO power supply. A few things I noticed. Transformer got hot, after it was running for 15 mins you couldn't touch it. Smelled like it was burning. Heater voltage would vary from 3v up to the normal 6.3v. Had some 60cy hum that could be quenched by connecting an earth ground but there was a fair amount of sparking when connecting the ground wire.
If you do find that it's bad it may be cheaper to have a custom one made or rewinding your old one as Hammond are costly. Unfortunately with a set that has 2.5v tubes it really limits the possibilities for replacement. A transformer out of a 70 has the voltage but I don't think it will make enough current.

Terry


Messages In This Thread
Philco 90 filament section on PT bad - by Skip - 04-02-2016, 02:08 PM
RE: Philco 90 filament section on PT bad - by Radioroslyn - 04-02-2016, 07:39 PM
RE: Philco 90 filament section on PT bad - by OZ4 - 04-03-2016, 12:02 PM



Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
54C Complete Teardown/Rebuild
Hello Roy, here is this one sincerely Richardradiorich — 12:45 AM
54C Complete Teardown/Rebuild
Richard, Had grabbed it already but thank you just the same.  I find myself wanting to find some way to block out the...glyphmon — 12:03 AM
54C Complete Teardown/Rebuild
Hello roy, here is a link to the schematic . Sincerely Richardradiorich — 11:54 PM
54C Complete Teardown/Rebuild
Richard, The Silvertone 2014 also is a transformerless set, so I am incorporating a 1:1 600 ohm audio isolation transfo...glyphmon — 11:37 PM
Preliminary work on wife's Silvertone 2014
Did an alignment today which was interesting.  IF alignment went great, almost all was already spot-on.  Adjusting on th...glyphmon — 11:35 PM
54C Complete Teardown/Rebuild
The main problem with adding a Bluetooth input is that this set lacks a traditional power transformer to isolate it from...radiorich — 11:19 PM
54C Cabinet Refinish
I started stripping this cabinet before it got super chilly out because I knew I wasn't going to be able to work on ...glyphmon — 11:18 PM
54C Complete Teardown/Rebuild
While I'm waiting to wrap up the final steps on my wife's Silvertone 2014, I started disassembly on the next project.  O...glyphmon — 11:07 PM
Preliminary work on wife's Silvertone 2014
Hello roy, that great news glad it worked out for you !! Sincerely Richardradiorich — 10:50 PM
Preliminary work on wife's Silvertone 2014
Safety caps arrived today.  Soldered one in and had a successful first power-up.  No magic smoke escaped and it tunes in...glyphmon — 09:53 PM

[-]
Who's Online
There are currently 2108 online users. [Complete List]
» 1 Member(s) | 2107 Guest(s)
Avatar

>