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

Thread Closed

Philco 38-12 no reception...
#3

This is what I would do. Connect your signal generator the grid cap of the 6A7 and the chassis. Set the generator to 470kc and align the two IF transformers. All three trimmers should have a pronounced peak if not check the winding for continuity.

Alter that is done measure the dc voltage on the 6A7's control grid (pin5) w/a high impedance volt meter (no vom). Should see some negative voltage there (a volt or 2) if the osc is running. You take a listen for it as Mike mention but may be nowhere near where it should be (470kc + the dial frequency). If not disconnect the wire connected to pin 1 of the osc coil and measure the resistance across the osc side of the tuning cap while rotating it from one end to the other. Should show no resistance at all (open). If not find the bent plate and straighten.

Check for hv on the screen grid of the 6A7 (pin4). If not osc coil is miss wired or open. Reverse the wires on pins 3 and 4 on the osc coil. Check #5 and 6 for tolerance. #6 can be substituted w/a 100mmfd cap.

GL

When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got it!

Terry


Messages In This Thread
Philco 38-12 no reception... - by sdradioman - 11-18-2018, 11:48 AM
RE: Philco 38-12 no reception... - by morzh - 11-18-2018, 01:54 PM
RE: Philco 38-12 no reception... - by Radioroslyn - 11-18-2018, 03:14 PM



Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
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
Stromberg Carlson 1500 Squeal
And life just keeps getting more complicated.dconant — 07:57 AM
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

[-]
Who's Online
There are currently 2225 online users. [Complete List]
» 1 Member(s) | 2224 Guest(s)
Avatar

>