Next 38-690 question

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

Linear Mode

Next 38-690 question

Ron Ramirez
Silent Key

Posts: 13,776
Threads: 580
Joined: Sep 2005
City: Ferdinand State, Province, Country: Indiana

#15

01-01-2016, 12:10 AM

I'm thinking you may have a burned carbon track in your band switch, in the oscillator section. Which of course is not good news. Icon_sad

Either that, or something is shorting B+ to ground to drop your B+ voltage that much when the band switch is in one of the SW positions.

Some careful resistance measurements (with the set of and unplugged) might reveal the source of the trouble. I would measure resistance between the B+ line (both sides of resistor (44) and from there up to the oscillator "plate" or grid #2 of the 6A8G oscillator tube) and chassis ground with the set in all four of the SW positions. Also take these measurements in the AM position as a reference.

--
Ron Ramirez
Ferdinand IN

Find

« Next Oldest | Next Newest »

Thread Closed

Messages In This Thread

38-690 wiring question - by DKinYORKpa - 12-20-2015, 03:39 PM

RE: Next 38-690 question - by klondike98 - 12-28-2015, 11:07 PM

RE: Next 38-690 question - by Ron Ramirez - 12-29-2015, 06:52 AM

RE: Next 38-690 question - by DKinYORKpa - 12-29-2015, 11:52 AM

RE: Next 38-690 question - by Radioroslyn - 12-31-2015, 09:02 PM

RE: Next 38-690 question - by Ron Ramirez - 01-01-2016, 12:10 AM

RE: Next 38-690 question - by DKinYORKpa - 01-01-2016, 10:25 AM

RE: 38-690 wiring question - by Phlogiston - 12-20-2015, 04:18 PM

RE: 38-690 wiring question - by DKinYORKpa - 12-20-2015, 04:36 PM

RE: 38-690 wiring question - by DKinYORKpa - 12-20-2015, 04:44 PM

RE: 38-690 wiring question - by SteveJB - 12-22-2015, 11:02 PM

Next 38-690 question - by DKinYORKpa - 12-24-2015, 01:11 PM

RE: Next 38-690 question - by morzh - 12-24-2015, 07:09 PM

RE: Next 38-690 question - by Radioroslyn - 12-24-2015, 08:00 PM

RE: Next 38-690 question - by DKinYORKpa - 12-27-2015, 06:23 PM

38-690 SW bands - by DKinYORKpa - 12-28-2015, 07:23 PM

View a Printable Version

Users browsing this thread: 6 Guest(s)

Recent Posts
B&K 1077B no video
I'm going to get back into it tonight. but I disconnected the 2 main resistors off this supply going to different parts ...TV MAN — 04:04 PM
6TPZ and 5TPO Radio Help
Sorry. The test points are as follows: 1 - 0v 2 - 0v 3 - 0v 4 - 12v 5 - 0v 6 - 11.9v 7 - 12v 8 - 12v 9 - 12v...R3Sons — 02:09 PM
6TPZ and 5TPO Radio Help
OK, so 18 and 19 as they should be. What is "everything else?" Try to be more specific in your descriptions:...morzh — 12:44 PM
6TPZ and 5TPO Radio Help
Yeah, I'm still on 5TPO. Sorry, my bad, points 1 and 2 should be points 18 and 19 (easy mistake :think: ) X7 is shown ...R3Sons — 11:42 AM
Philco 40-120C Filament Wiring
Hi folks, I'm in the process of restoring a Philco 40-120C and I'm finding the wiring to be a bit puzzling. According to...bluecap — 11:28 AM
462ron
Hi Levi, here’s just a thought. Most radios run the oscillator higher than the dial setting. Say you set your radio to 1...462ron — 10:10 AM
1930s Stewart-Warner Tombstone Radio need help identifying model number
Another Update: I found a couple of damaged coils inside this radio that might have something to do with why this radio ...captainclock1988 — 10:51 PM
6TPZ and 5TPO Radio Help
If you are still on 5TPO, you lost me there. What X7? What Points 1 and 2?morzh — 08:37 PM
6TPZ and 5TPO Radio Help
Quick progress report: X7 is broken. Only one leg soldered, the other missing and the diode is cracked. I've replaced...R3Sons — 05:05 PM
6TPZ and 5TPO Radio Help
Oh...and you have electrolytic caps there. All need to go and be replaced.morzh — 04:36 PM

Who's Online

There are currently 6465 online users. [Complete List]
» 2 Member(s) | 6463 Guest(s)

Login
Username:
Password:	Lost Password?
	Remember me