Navaho TRC-458 Base Output Problems

[AudioShockwav]

I have a TRC-458 that has a rf output problem of some sort. It only puts out about a watt or up to 1.5 watts, and the strangest thing happens when you spray CRC tuner cleaner around coil L-39, the watts jump back up to 4 watts, and as the tuner cleaner dissipates, the watts slowly goes back down to about a watt or, watt and a half. Not sure what is going on, but could it be a bad solder joint in that region, or a hairline crack? Anybody have any ideas?

Good pictures of the area are helpful, it really sounds like a bad solder joint.
Have you tried reflowing the areas where it connects to the board?
Use a plastic tuning tool and press around on the board there, does it change anything?
I don't know the board, are there any other components close to the inductor that may be effected by the cooling effect of the cleaner?

73
Jeff

 

[Tom Kaufman]

I have a TRC-458 that has a rf output problem of some sort. It only puts out about a watt or up to 1.5 watts, and the strangest thing happens when you spray CRC tuner cleaner around coil L-39, the watts jump back up to 4 watts, and as the tuner cleaner dissipates, the watts slowly goes back down to about a watt or, watt and a half. Not sure what is going on, but could it be a bad solder joint in that region, or a hairline crack? Anybody have any ideas?

I think I found the culprit. A toroid coil. L35 is wobbley. Now I just gotta find one.

 

[Tom Kaufman]

I have a TRC-458 that has a rf output problem of some sort. It only puts out about a watt or up to 1.5 watts, and the strangest thing happens when you spray CRC tuner cleaner around coil L-39, the watts jump back up to 4 watts, and as the tuner cleaner dissipates, the watts slowly goes back down to about a watt or, watt and a half. Not sure what is going on, but could it be a bad solder joint in that region, or a hairline crack? Anybody have any ideas?

I found the culprit, L-35, it is a toroid coil, but I'm having a hard time finding a new one to replace it.

 

[Tom Kaufman]

I found the culprit, L-35, it is a toroid coil, but I'm having a hard time finding a new one to replace it.

Done some free flowing, no relief yet.

 

[Cable Guy]

Done some free flowing, no relief yet.

Can you rewind it, maybe you have a transformer laying around with the same diameter wire?

 

[Tom Kaufman]

Can you rewind it, maybe you have a transformer laying around with the same diameter wire?

No, I don't have any that size. but the further i investigate, the more I'm not so ure that is causing the problem. The beeswax has somehow melted away from the bottom where the wires are attached to the board, but best I can tell, they are all still intact. And using the tuner cleaner sprayed at the bottom of L39, still briefly eliminates the problem. FET 6 which is the xmit, is right next to L-39, and maybe it may need replacing, got to do more checking.