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

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

Model 38 serive bulletin No. 120-c Alignment
#1

Just finishing up a Model 38. Looking for information on alignment. I have the ryders info about compensating condensors and placement so was able to do an alignment of the IF to 460 Khz. However I dont seem to be able to get the alignment to track on the dial. Also any information on how the band switch works, there is nothing changing the oscillator circuit that I can see. Just adding two caps to the rf coil seconday top and tap. Broadcast band is working but police sw is not. Just gets oscillations. Coils all check ok.
Thanks in advanvce to anyones help.
David
Icon_confused:
#2

If you have already replaced wax-paper caps and checked all resistors for proper values (+/-20% max), then this Service Tip from my site may help.

PHILCO SERVICE HINTS & TIPS - NUMBER 26
Oscillator Failure in Model 38


The old, not used "police" band is nothing more than the standard AM band with an extended top end freq range to about 2,000 kHz or so.

You may want to try replacing the mica caps in the front end with exact value repalcements and/or cleaning the mica sheets in the compensating trimmer, part #14, 7, 6 in the Code 121 version. The front end is a more complicated circuit in the Code 123 version, parts are numbered the same.

Be sure you have the proper schematic for your set. You can tell because the early version uses a type 15 mixer and the later, Code 123, uses a 1A6 in the front end.




Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
B&K 1077B no video
Hello Tim, I would if it's a leaky Capacitor So are all 3 of those B- voltages low then ? Sincerely Richardradiorich — 01:55 AM
B&K 1077B no video
I found a schematic and think I have the problem traced down to the minus power supply. I have very low voltages that go...TV MAN — 12:41 AM
RCA 15X
I'd try replacing the bulb first and if that doesn't do it, then change the 35Z5 and see if the problem goes away.NostalgiaRadioTime — 12:28 AM
B&K 1077B no video
Hello Tim, I have that exact unit in my shop too plus a Sencore unit there are times I like one or other !!. Sincerely...radiorich — 11:07 PM
RCA 15X
Everthing goes at once, maybe it's the cold weather, I have had 2 dial strings break and no my little RCA is having dial...Paul Philco322 — 10:26 PM
Philco 91 Schematic
Hi Dan, I can't explain this specific resistor but I have seen the use of a switch to apply B+ voltage to screen gri...RodB — 09:36 PM
6TPZ and 5TPO Radio Help
I suspect it's been repaired before. And I suspect whoever repaired it, wanted to re-use old transistors' pin stubs in o...morzh — 09:24 PM
B&K 1077B no video
Thanks Rich! I'll take a look and see what he has. I know there's more modern equipment to be had, but this one I know a...TV MAN — 09:11 PM
B&K 1077B no video
Hello Tim, Here is a link to restoration of one on Phil's old radios site ! Sincerely Richard bk1077bradiorich — 09:01 PM
6TPZ and 5TPO Radio Help
I'm a little befuddled on this one. Should X5 and X4 be tied together like this?  It looks like someone added this at so...R3Sons — 07:33 PM

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

>