magnum 257 help

[stubags99]

i have a magnum 257 theradio will tx and rx ok but i have a deadcarrier no mod any 1 know whats wrong could it be the microphone any help please

[nomadradio]

Microphones break far more frequently than radios. The cord is the number one failure, especially where it enters the mike, or the plug.

If you don't have another mike to try on the radio, or another radio to try on the mke, this is a lot more trouble.

Taking apart something that isn't 'broke' could end up being 'broke' if anything goes wrong putting it back together.

Somebody (else) needs to put up a web page showing how to test a mike with only a DVM or analog test meter.

Do you have a wattmeter, so you can tell what's coming out of the radio?

If the radio's carrier power jumped 'way up when it stopped modulating, that could be a clue, too.

73

[stubags99]

ok will test radios output and then try to find a new mike not easy for me to find one here if not will try to find another opperaitor with one to try thanks

[stubags99]

the radio will key tx and rx fm but noton am ssb is that because theres no mod from the mike on ssb am thanks radio seams to be outputing right power

[Rick]

Is the radio working on FM? Have you tried for a radio report on FM? If FM is working ok then try replacing Q78 (2SB778) this is the transistor bolted to the side on the radio. Hope this helps.

Rick.

[zodiac]

Fault found and fixed. It was a 4.7mH coil (surface mount) the same fault as found with the Delta Force. If the centre pin on the mic socket don't have 13v on it then the coil is open circuit and needs replacing.
Dave