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 - someone's been in here before!
#5

I managed to re-wind the coil.  Didn't come out too badly.  I removed the old winding along with the celluloid material, cleaned it with rubbing alcohol, and baked it in the oven at 200 for about 25 minutes.  Then, I used green masking tape as an insulator, and I added roughly 100 turns of AWG 34 copper wire on it, and sprayed it with clear lacquer to protect it.  

   

After reinstalling it in the radio I still had no reception.  I used a little Emerson transistor radio to determine the oscillator was running.  Trying to feed a 175kc signal into the antenna terminal resulted in a barely audible sound from the radio.  I checked the voltages, and figured out that all of the screens in the front end were missing voltages - which they get through a 25k resistor, which, I had connected to the wrong terminal after redoing a bakelite block.  Ugh!  After fixing that, it plays.  

   

A couple things I noticed - it seems very sensitive and selective for an early radio.  Tons of volume, but sound quality is only ok - I'm thinking due to the primitive speaker with a stiff spider.  Also, voltages are all high - probably because of the replacement transformer.  B+ at the rectifier is 310v, so I need to find a way to reduce that.  I also noticed (how I missed this before, I have no idea), all tubes except for the 47 are 6.3v equivalents of the originals, obviously whoever worked on it had trouble finding a transformer with a 2.5v winding.  I don't blame them for converting it over.

I tried to adjust the oscillator at 600kc, and found the adjustment didn't do much.  I might just leave it, it works ok.  I also really need to get grommets for the tuning capacitor, it's completely loose.


Messages In This Thread
RE: Philco 90 - someone's been in here before! - by adamrobertg - 09-11-2025, 08:22 PM



Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
Stromberg Carlson 1500 Squeal
And life just keeps getting more complicated. By dconant. Dittos'Jimradio — 08:01 AM
Plug Voltages Needed For A 1943 CRV-20130 Power Supply
That looks a lot like an aircraft connector of some kind, even if it's a U.S.N power supply. I have a book somewhere abo...Arran — 02:56 AM
Plug Voltages Needed For A 1943 CRV-20130 Power Supply
hello david, I have a similar generator in my collection that features a cast iron, single-cylinder Briggs & Stratt...radiorich — 01:00 AM
under chassis parts locator diagram for 1938 Zenith 9s262
Has anyone gone to the trouble of creating an under chassis parts locator image?  Yes, I can identify components by foll...bobloney — 08:57 PM
Plug Voltages Needed For A 1943 CRV-20130 Power Supply
Try looking at this site the book mark is for a old generator that I was given. David    https://radionerds.com/index.ph...David — 08:36 PM
Plug Voltages Needed For A 1943 CRV-20130 Power Supply
Hello Everyone, I am looking for voltage identification for all the pin positions on the socket of a CRV-20130 power su...Tonym4704 — 08:16 PM
Philco P45-6365 Universal Transformer Instruction Manual
Can anyone guide me to where this may be found?GRG — 03:00 PM
54C Complete Teardown/Rebuild
I don't think that I have encountered a 12Z3 before, curious how it uses one of those but includes a #43, which is a 25 ...Arran — 02:17 PM
HiFi (Chifi) tube amp build - but my own design.
It's the other forum. I'm also in DIY, but mostly read there. Honestly, I kinda jumped into this without much thought to...TV MAN — 10:43 AM
Philco 71 Code 125
Hello,  I am in need of a schematic for this radio. Mine has the three separate circular tube shields and a shadow me...dconant — 08:06 AM

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

>