6 volt auto radio problem

9/6/2008 12:47:27 AMdel in MN

1950 Chevrolet, 6 v negative ground. I had it running really nice for quite a while. I had put in the usual new caps and filters, new solid state vibrator, buffer cap. Then I put it aside until the customer comes. Tried it after 2 weeks and it blows 5 amp fuse. Tried again, blow 5 amp fuse again. I checked continuity between 6 v+ and chassis and found none, but when I turned the switch on there was continuty between the 6 volt+ line in and the switch shaft. The switch shaft also has continuity to negative. It seems like the switch went bad. What do you think?

9/6/2008 12:52:56 AMdel in MN

Also the pilot light does light anymore. It has a separate 6 volt + lead in from the main switch.

9/6/2008 11:08:58 AMEdd

Give me a model / schematic number to check against, but, in the interim, try out the unit with out the solid state vibro-fumator
plugged in.

73's de Edd

9/6/2008 11:28:57 AMdel in MN(65618:65616)

Could not find model number at all on the in or out of the set. I had it working well then it started blowing fuses, 5 or so at the 5 amp level. Then it stopped doing that and I found no 6v anyplace. I did another 6v radio and had to put in a side on/off switch to get it to work (and it does). But this one has the switch so deep in the chassis that I cannot get at anything to put external switch in. I am giving up. With the vibrator out I still get nothing. The switch must be a goner. I am giving up on this one. Thanks Edd

9/6/2008 11:55:58 AMdel in MN(65619:65618)

Not giving up just yet in that it did work for 2 weeks before it started blowing 5 amp fuses. No model #. Uses 6SK7, 6SA7, 6SK7, 6SQ7 and 6V6, OZ4. Thanks

9/6/2008 1:32:35 PMdel in MN(65620:65619)

I have 6 v on 3 of the 4 switch positions with the 4th to ground. I have 6v on the two sides of the spark plate by the switch. I have no heater 6v on the leads from the switch to the 6SQ7 which seems to be the first of the heaters in the series from the switch. Vibrator is still out of the set. No pilot light even though there is a line to the light and 6v on the back of the switch for its supply. That light is impossible to get to for replacing but it did work before. This radio did work well off and on for about 2 weeks, then pop went the 5 amp fuse. Thanks.

9/6/2008 6:53:17 PMdel in MN(65624:65620)

The 6SQ7 was the wrong tube in the set. It should be the 6V6. I need to order one of those. I must have 'what is his name disease' as I was the only one who worked on this set and I do not recall put an 6SQ7 in the 6V6 socket. Dumber each day, I guess.

9/6/2008 7:04:38 PMMarv Nuce(65625:65624)

Del,
The disease is called CRS "Can't Remember Shxx"
marv
:The 6SQ7 was the wrong tube in the set. It should be the 6V6. I need to order one of those. I must have 'what is his name disease' as I was the only one who worked on this set and I do not recall put an 6SQ7 in the 6V6 socket. Dumber each day, I guess.

9/7/2008 3:41:21 AMMAG(65640:65619)

If it is a 1950 Chevy radio with those tubes, it must be the truck radio: model 986443 or maybe the 1947-49 truck radio model 986067. The 1950 Chevy car radio was a 2-piece design and used miniature tubes in the tuning section.

:Not giving up just yet in that it did work for 2 weeks before it started blowing 5 amp fuses. No model #. Uses 6SK7, 6SA7, 6SK7, 6SQ7 and 6V6, OZ4. Thanks

9/7/2008 4:40:20 AMdel in MN(65642:65640)

Thanks for help, Still trying to get 6 volts to the heaters, must be the switch. So far I cannot see on the radio where the 6 volt line is from the switch. A partial schematic came from the owner who brought the back of the radio after he found it (he said he knew where it was). The partial schematic shows a model numnber with only the last 2 digits as .......77. I think the 986443 schematic will be the same. Thanks.
:If it is a 1950 Chevy radio with those tubes, it must be the truck radio: model 986443 or maybe the 1947-49 truck radio model 986067. The 1950 Chevy car radio was a 2-piece design and used miniature tubes in the tuning section.
:
:
::Not giving up just yet in that it did work for 2 weeks before it started blowing 5 amp fuses. No model #. Uses 6SK7, 6SA7, 6SK7, 6SQ7 and 6V6, OZ4. Thanks

9/7/2008 7:55:05 AMBill VA(65643:65642)

:Thanks for help, Still trying to get 6 volts to the heaters, must be the switch. So far I cannot see on the radio where the 6 volt line is from the switch. A partial schematic came from the owner who brought the back of the radio after he found it (he said he knew where it was). The partial schematic shows a model numnber with only the last 2 digits as .......77. I think the 986443 schematic will be the same. Thanks.
Delco....
Bill

:
:
:
::If it is a 1950 Chevy radio with those tubes, it must be the truck radio: model 986443 or maybe the 1947-49 truck radio model 986067. The 1950 Chevy car radio was a 2-piece design and used miniature tubes in the tuning section.
::
::
:::Not giving up just yet in that it did work for 2 weeks before it started blowing 5 amp fuses. No model #. Uses 6SK7, 6SA7, 6SK7, 6SQ7 and 6V6, OZ4. Thanks

9/7/2008 8:08:20 AMdel in MN(65644:65643)

Thanks for the schematic which I printed.

9/7/2008 5:52:33 PMMAG(65647:65644)

Hi Del,
It just dawned on me that you said the radio was blowing 5 amp fuses. Not too surprising since the radio normally draws 6 amps at 6 volts!! The proper fuse would be an SFE-14 (rated 14 amps at 32 volts).
The GMC 2233297 schematic Bill posted is identical to the Chevy 986443 schematic. The only difference between the two radios is the dial: GMC logo versus Chevrolet Logo.
I don't know of any U.S built Delco radios from the 50's era that have model numbers ending in "77"--maybe a Canadian radio?
Meade
:Thanks for the schematic which I printed.

9/7/2008 6:32:35 PMdel in MN(65648:65647)

Thanks. Still working on it. But need to let it go for a while. Still cannot get 6 volts to the heaters.

9/8/2008 5:58:14 PMEdd(65678:65648)

I guess that I had merely retained FORD in memory cache , when in reality, the unit was a GM product.
Looking thru all of the olde
Schemas on hand, I was mostly finding big ‘ole heavy “Catteracks” models with push-um-pullem AF output stages.
Sooo. . . .I just
pulled out the schema for the “lil Henry J of that time frame, I suppose that it didn’t have enough horse-powders to
tote around that
extra 6V6.
The unit shows to be having the dual switch mentioned with very little circuit components tied in but a few bypassing
caps and
spark gap plates.

Reference Schema:

73's de Edd

9/8/2008 7:23:10 PMdel in MN(65680:65678)

The chassis layout is the exact match. I still need to find the 6 v lead to the heaters when I get back to it. Thanks Edd

9/9/2008 10:04:24 PMdel in MN(65718:65680)

I found the 6 v lead from the switch and replaced with an external switch. Thanks for help.

9/9/2008 10:04:56 PMdel in MN(65719:65718)

It works wonderfully now.