When I turn on this GE T-202 A, the AM always comes on, but the FM doesn't. However, if turned on several times, the FM comes on and works great with no distortion or drift. Sometimes, but very rarely, it will come on by itself, and when it does it sounds like a tube warming up. It's a hybrid tube-printed circuit board, so I've done the obvious resoldering around tube sockets, power leads, IF cans, etc, and sprayed the tube sockets with contact cleaner. I don't think it's the function switch, although it could be. I can't find a schematic and my tube manuals are too old for most of the tubes. There are two interesting problems- there is a screw missing from one of the trimmers on the tuning cap, and someone replaced a 12AU6 with a 12BA6. However, these don't keep it from working-sometimes. I've messed with this all afternoon and could use a fresh perspective. So, I would appreciate any ideas or insights. Thanks, Terry
(I know, it's kind of sad that the only thing I have to do on Christmas day is mess with an old radio-but I'm getting the laundry done too, so there.)

Terry,
Check my post to Thomas D, 12-18 under "handfull"

marv

:When I turn on this GE T-202 A, the AM always comes on, but the FM doesn't. However, if turned on several times, the FM comes on and works great with no distortion or drift. Sometimes, but very rarely, it will come on by itself, and when it does it sounds like a tube warming up. It's a hybrid tube-printed circuit board, so I've done the obvious resoldering around tube sockets, power leads, IF cans, etc, and sprayed the tube sockets with contact cleaner. I don't think it's the function switch, although it could be. I can't find a schematic and my tube manuals are too old for most of the tubes. There are two interesting problems- there is a screw missing from one of the trimmers on the tuning cap, and someone replaced a 12AU6 with a 12BA6. However, these don't keep it from working-sometimes. I've messed with this all afternoon and could use a fresh perspective. So, I would appreciate any ideas or insights. Thanks, Terry
:(I know, it's kind of sad that the only thing I have to do on Christmas day is mess with an old radio-but I'm getting the laundry done too, so there.)
:

:Terry,
:Check my post to Thomas D, 12-18 under "handfull"
:
:marv
:
::When I turn on this GE T-202 A, the AM always comes on, but the FM doesn't. However, if turned on several times, the FM comes on and works great with no distortion or drift. Sometimes, but very rarely, it will come on by itself, and when it does it sounds like a tube warming up. It's a hybrid tube-printed circuit board, so I've done the obvious resoldering around tube sockets, power leads, IF cans, etc, and sprayed the tube sockets with contact cleaner. I don't think it's the function switch, although it could be. I can't find a schematic and my tube manuals are too old for most of the tubes. There are two interesting problems- there is a screw missing from one of the trimmers on the tuning cap, and someone replaced a 12AU6 with a 12BA6. However, these don't keep it from working-sometimes. I've messed with this all afternoon and could use a fresh perspective. So, I would appreciate any ideas or insights. Thanks, Terry
::(I know, it's kind of sad that the only thing I have to do on Christmas day is mess with an old radio-but I'm getting the laundry done too, so there.)
::
:

...So the sound fades in like a tube warming up?

This eliminates silver mica disease for the most part, because that is often associated with crackling and popping and sudden changes.

Have you made sure that all of the tubes are lit up when the FM is dead?

Check all resistors for drifting/opening. If a resistor is open and then closes, and feeds a large value capacitor, things might come back to life slowly, like a tube warming up.

Is the trimmer associated with the AM or FM? If it's associated with AM, worry about it later. AM is easy to align anyway. Actually, if it's on the tuning capacitor and it relates to FM, this is an easy adjustment, too. The only difficult adjustments are the IF transformers. The tuning capacitor can be aligned to actual stations, and no scope or sweep generator is needed.

T.

Terry,
Might consider cleaning individual sockets for every tube pin, especially any you suspect of causing the fade in/out problem. Several recommendations have been made for this process, ie swiss files, pipe cleaners with solvent, reamers for gas welding torches. I've even used good strong silver plated stranded wire, in hopes of a silver migration to the socket.

marv

::Terry,
::Check my post to Thomas D, 12-18 under "handfull"
::
::marv
::
:::When I turn on this GE T-202 A, the AM always comes on, but the FM doesn't. However, if turned on several times, the FM comes on and works great with no distortion or drift. Sometimes, but very rarely, it will come on by itself, and when it does it sounds like a tube warming up. It's a hybrid tube-printed circuit board, so I've done the obvious resoldering around tube sockets, power leads, IF cans, etc, and sprayed the tube sockets with contact cleaner. I don't think it's the function switch, although it could be. I can't find a schematic and my tube manuals are too old for most of the tubes. There are two interesting problems- there is a screw missing from one of the trimmers on the tuning cap, and someone replaced a 12AU6 with a 12BA6. However, these don't keep it from working-sometimes. I've messed with this all afternoon and could use a fresh perspective. So, I would appreciate any ideas or insights. Thanks, Terry
:::(I know, it's kind of sad that the only thing I have to do on Christmas day is mess with an old radio-but I'm getting the laundry done too, so there.)
:::
::
:
:I know, I hate these circuit boards. Did you ever deal with those early Zenith TV's? Like I said, I've re-soldered every spot I could hit, especially around the tube sockets and the switch. I also went over it with some cold spray. I've washed the switch with contact spray and WD-40. If it was removable I'd pull it. However, it's hooked up to a mechanical linkage and is riveted in. I'm going to replace the 12AU6 but I don't have one lying around. I don't think that's the problem anyway. I'm not that concerned about the missing trimmer screw since it DOES work. I'd hate to mess with re-alignment too. It'd be nice to have the schematic so I could do some signal tracing and voltage measurements. The main clue is that it does come on. It's a real nice radio that looks and sounds great. Don't ya hate intermmitent problems?
:

:Terry,
:Might consider cleaning individual sockets for every tube pin, especially any you suspect of causing the fade in/out problem. Several recommendations have been made for this process, ie swiss files, pipe cleaners with solvent, reamers for gas welding torches. I've even used good strong silver plated stranded wire, in hopes of a silver migration to the socket.
:
:marv
:
:::Terry,
:::Check my post to Thomas D, 12-18 under "handfull"
:::
:::marv
:::
::::When I turn on this GE T-202 A, the AM always comes on, but the FM doesn't. However, if turned on several times, the FM comes on and works great with no distortion or drift. Sometimes, but very rarely, it will come on by itself, and when it does it sounds like a tube warming up. It's a hybrid tube-printed circuit board, so I've done the obvious resoldering around tube sockets, power leads, IF cans, etc, and sprayed the tube sockets with contact cleaner. I don't think it's the function switch, although it could be. I can't find a schematic and my tube manuals are too old for most of the tubes. There are two interesting problems- there is a screw missing from one of the trimmers on the tuning cap, and someone replaced a 12AU6 with a 12BA6. However, these don't keep it from working-sometimes. I've messed with this all afternoon and could use a fresh perspective. So, I would appreciate any ideas or insights. Thanks, Terry
::::(I know, it's kind of sad that the only thing I have to do on Christmas day is mess with an old radio-but I'm getting the laundry done too, so there.)
::::
:::
::
::I know, I hate these circuit boards. Did you ever deal with those early Zenith TV's? Like I said, I've re-soldered every spot I could hit, especially around the tube sockets and the switch. I also went over it with some cold spray. I've washed the switch with contact spray and WD-40. If it was removable I'd pull it. However, it's hooked up to a mechanical linkage and is riveted in. I'm going to replace the 12AU6 but I don't have one lying around. I don't think that's the problem anyway. I'm not that concerned about the missing trimmer screw since it DOES work. I'd hate to mess with re-alignment too. It'd be nice to have the schematic so I could do some signal tracing and voltage measurements. The main clue is that it does come on. It's a real nice radio that looks and sounds great. Don't ya hate intermmitent problems?
::
:
Thanks for all of the great advice. That's why I love this site.
Terry

Don't foret the pins on the tubes too. Sometimes they get oxidied and don't make contact with even with a properly cleaned and tensioned tube socket that is free of cracks and arc traces. I like to use an old dental explorer or craft nife to scrape them clean, after removing all grease and soot from the pins,and the glass between them. If you use paint thinner, you won't lose the decals on the tube which are usually water soluble. Otherwise, know which tube you are cleaning up before you do it. I assume you have also replaced all the greasy leaky paper capacitors with new ones, and also the resistors that have drifted up in value more than 20%. And finally, a diseased mica may test perfectly out of circuit so far as ohms, but may fail miserably with only a few volts applied to them. Depending where they are, you may not get the snap cracle and pop, but just no signal at all, An ancient capacitor tester will nail this down, but a lifetime supply of little caps in varying values is cheaper and easier than acquiring the equipment, restoring it, and learning how to use it, so I have found out. By the time you have carefully unsoldered one end of the little critter, it is just as practical to replace it than measure it. But, it's also just nice to know when you found the bad part. I guess that's what this hobby is all about.

Best regards

::Terry,
::Might consider cleaning individual sockets for every tube pin, especially any you suspect of causing the fade in/out problem. Several recommendations have been made for this process, ie swiss files, pipe cleaners with solvent, reamers for gas welding torches. I've even used good strong silver plated stranded wire, in hopes of a silver migration to the socket.
::
::marv
::
::::Terry,
::::Check my post to Thomas D, 12-18 under "handfull"
::::
::::marv
::::
:::::When I turn on this GE T-202 A, the AM always comes on, but the FM doesn't. However, if turned on several times, the FM comes on and works great with no distortion or drift. Sometimes, but very rarely, it will come on by itself, and when it does it sounds like a tube warming up. It's a hybrid tube-printed circuit board, so I've done the obvious resoldering around tube sockets, power leads, IF cans, etc, and sprayed the tube sockets with contact cleaner. I don't think it's the function switch, although it could be. I can't find a schematic and my tube manuals are too old for most of the tubes. There are two interesting problems- there is a screw missing from one of the trimmers on the tuning cap, and someone replaced a 12AU6 with a 12BA6. However, these don't keep it from working-sometimes. I've messed with this all afternoon and could use a fresh perspective. So, I would appreciate any ideas or insights. Thanks, Terry
:::::(I know, it's kind of sad that the only thing I have to do on Christmas day is mess with an old radio-but I'm getting the laundry done too, so there.)
:::::
::::
:::
:::I know, I hate these circuit boards. Did you ever deal with those early Zenith TV's? Like I said, I've re-soldered every spot I could hit, especially around the tube sockets and the switch. I also went over it with some cold spray. I've washed the switch with contact spray and WD-40. If it was removable I'd pull it. However, it's hooked up to a mechanical linkage and is riveted in. I'm going to replace the 12AU6 but I don't have one lying around. I don't think that's the problem anyway. I'm not that concerned about the missing trimmer screw since it DOES work. I'd hate to mess with re-alignment too. It'd be nice to have the schematic so I could do some signal tracing and voltage measurements. The main clue is that it does come on. It's a real nice radio that looks and sounds great. Don't ya hate intermmitent problems?
:::
::
:
:I received the schematic in this morning's email. Thanks Bill! Hopefully, that will help me pinpoint the problem. I REALLY hope it's not the switch.
:Thanks for all of the great advice. That's why I love this site.
:Terry
:

Terry: I believe your problem lies in the FM local oscillator not firing up. This can be caused by a legion of things. Check the B+ value on the plate of the osc. tube and also insert another tube. Also check the overall B+ line of the set to see if it is up to par. You are "shocking" the oscillator and causing it to start when you operate the bandswitch and the fault is not in the switch itself.

:When I turn on this GE T-202 A, the AM always comes on, but the FM doesn't. However, if turned on several times, the FM comes on and works great with no distortion or drift. Sometimes, but very rarely, it will come on by itself, and when it does it sounds like a tube warming up. It's a hybrid tube-printed circuit board, so I've done the obvious resoldering around tube sockets, power leads, IF cans, etc, and sprayed the tube sockets with contact cleaner. I don't think it's the function switch, although it could be. I can't find a schematic and my tube manuals are too old for most of the tubes. There are two interesting problems- there is a screw missing from one of the trimmers on the tuning cap, and someone replaced a 12AU6 with a 12BA6. However, these don't keep it from working-sometimes. I've messed with this all afternoon and could use a fresh perspective. So, I would appreciate any ideas or insights. Thanks, Terry
:(I know, it's kind of sad that the only thing I have to do on Christmas day is mess with an old radio-but I'm getting the laundry done too, so there.)
:

:Terry: I believe your problem lies in the FM local oscillator not firing up. This can be caused by a legion of things. Check the B+ value on the plate of the osc. tube and also insert another tube. Also check the overall B+ line of the set to see if it is up to par. You are "shocking" the oscillator and causing it to start when you operate the bandswitch and the fault is not in the switch itself.
:
::When I turn on this GE T-202 A, the AM always comes on, but the FM doesn't. However, if turned on several times, the FM comes on and works great with no distortion or drift. Sometimes, but very rarely, it will come on by itself, and when it does it sounds like a tube warming up. It's a hybrid tube-printed circuit board, so I've done the obvious resoldering around tube sockets, power leads, IF cans, etc, and sprayed the tube sockets with contact cleaner. I don't think it's the function switch, although it could be. I can't find a schematic and my tube manuals are too old for most of the tubes. There are two interesting problems- there is a screw missing from one of the trimmers on the tuning cap, and someone replaced a 12AU6 with a 12BA6. However, these don't keep it from working-sometimes. I've messed with this all afternoon and could use a fresh perspective. So, I would appreciate any ideas or insights. Thanks, Terry
::(I know, it's kind of sad that the only thing I have to do on Christmas day is mess with an old radio-but I'm getting the laundry done too, so there.)
::
:
I like the suggestion about the osc. That sounds about right. I haven't had time to get back into the set yet today-but I have the schematic now. Instead of a movie that's my project for tonight.

I really appreciate all of these suggestions. It makes an old tech like me feel good to have such practical help available.
Thanks guys-
t.

Could also be an open resistor in the AGC circuit. An open resistor might allow the AGC circuit to saturate negatively, cutting out all reception. Then, with turning on and off the radio, a surge might bridge the resistor enough to slowly leak off the voltage, if the resistor is only opened just barely.

Probably not, but possibly.

T.

:Could also be an open resistor in the AGC circuit. An open resistor might allow the AGC circuit to saturate negatively, cutting out all reception. Then, with turning on and off the radio, a surge might bridge the resistor enough to slowly leak off the voltage, if the resistor is only opened just barely.
:
:Probably not, but possibly.
:
:T.
:

:When I turn on this GE T-202 A, the AM always comes on, but the FM doesn't. However, if turned on several times, the FM comes on and works great with no distortion or drift. Sometimes, but very rarely, it will come on by itself, and when it does it sounds like a tube warming up. It's a hybrid tube-printed circuit board, so I've done the obvious resoldering around tube sockets, power leads, IF cans, etc, and sprayed the tube sockets with contact cleaner. I don't think it's the function switch, although it could be. I can't find a schematic and my tube manuals are too old for most of the tubes. There are two interesting problems- there is a screw missing from one of the trimmers on the tuning cap, and someone replaced a 12AU6 with a 12BA6. However, these don't keep it from working-sometimes. I've messed with this all afternoon and could use a fresh perspective. So, I would appreciate any ideas or insights. Thanks, Terry
:(I know, it's kind of sad that the only thing I have to do on Christmas day is mess with an old radio-but I'm getting the laundry done too, so there.)
:
Thanks for all of the sugestions.
(I knew it wasn't the switch!)