Posts: 662
Threads: 142
Joined: Jun 2011
City: Elko,MN.
Hi Fella's,
Brought home a 1934 Crosley 6H2 radio last weekend and seem to have a problem.
Radio was previously recapped, tubes check ok etc.
Powered it up and could not receive a station anywhere on the dial.
Did notice though that if I put my hand on the 6B7 tube it would pick up stations as it normally would.
If I even pass my hand over the top of the tube it comes in. Strongest if I put my hand on the tube.
Had this problem with another radio and found that the bias cell was open, which opened the circuit going up to a tube grid cap.
Don't see a cell in this one.
Any suggestions?
Thanks and merry x-mas to all.
murf
Posts: 7,207
Threads: 266
Joined: Dec 2009
City: Roslyn Pa
Hi Murf and Merry Christmas
https://www.youtube.com/watch?v=Ooc5eJc5SHA
Bit odd. I would inject a 456kc modulated signal at the cap of the 6A7 and peak up the two IF transformers. Methinks someone has been dittling w/them.
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!
Terry
Posts: 662
Threads: 142
Joined: Jun 2011
City: Elko,MN.
Hi Terry,
I am afraid I don't have working equipment presently to do that.
If I just lay the chassis on its back so the 6B7 tube is touching the bench it comes alive the same as if I touch or grab the 6B7 tube.
Strange indeed.
Are those small cans mounted under the chassis coils or what?
They each have 4 or 5 leads attached to the bottom.
The schematics look very different from what I am used to.
Murf
Posts: 662
Threads: 142
Joined: Jun 2011
City: Elko,MN.
Terry,
You were right again.
I fired it up and tweeked the if cans and it came to life.
Seems there is a dead spot in one of the adjustment screws.
Murf
Posts: 15,278
Threads: 531
Joined: Oct 2011
City: Jackson, NJ
Usually a sign of open coils.
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
Posts: 7,207
Threads: 266
Joined: Dec 2009
City: Roslyn Pa
>Are those small cans mounted under the chassis coils or what?
Probably, post a pick to be sure.
>The schematics look very different from what I am used to.
Crosley are the worst for schematics. They are never straight forward it's like they are trying to obfuscate the circuit and tubes/parts. Most of the time the tubes are drawn upside down and have a number next to they than could be the type of tube but it's the part placement number. Big ones get me a headache!
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!
Terry
Posts: 662
Threads: 142
Joined: Jun 2011
City: Elko,MN.
Think now that it is playing, I will list it on CL and try to stay awY from these morphedites.
Thanks again.
Murf
Posts: 4,603
Threads: 50
Joined: Sep 2008
City: Sandwick, BC, CA
Murf;
Try touching up the solder joint on the 6B7 grid cap as well, and don't overlook the grid lead or it's clip, those things break internally near the grid cap clip sometimes. The 6B7 is a bit of an oddball tube, it's a pentode-double diode, just like it's octal cousin the 6B8/6B8G, not many radios used them, though more used the 6B7 then the later 6B8. Most manufacturers used a 6Q7/#75 or a 6R7, or if they wanted to tube stuff the chassis between 1936-38 they would use a 6F5 and a 6H6, more tubes equaled a "better" radio to the sales and marketing department.
Regards
Arran
