S/S 158-EDX Carrier but no Modulation...

[riveracc1]

This is for the radio techs. Yesterday my radio went bad. It's a Superstar 158 edx with dual mosfet finals. The echo board was unplugged and the variable for the echo was used for regulating am power.(Just jumped the 5k variable on the board to the 100k echo pot, touchy but works). Everything worked just fine for about a year up to yesterday. While I was keyed up adjusting DK, something went wrong. Now I have a steady carrier output of full power but no modulation comes out. If I modulate I can see the needle bounce a bit. The am power variable won't regulate. I uninstalled the mods and put everything back to where it's supposed to be and still the same. Changed mics and nothing. The talkback works fine, I can hear myself on the speaker and the mic gain works, I could adjust the gain up and down. Receiving is excellent and my locals said that they could hear me reallllllllll lowwwwwwwww but the power is there. I can't lower my power with the factory am power variable and I noticed a transistor was removed, Q40 or Q41 I can't remember. I think it's the audio limiter or maybe this model does'nt use it. Mic is a D104 Astatic and the input voltage is at 14.5 volts steady. Tried with another antenna ans the same. I checked the power regulator and it works, and the mic preamp IC has the voltage on the B+ terminal. My tech is on vacations and I just want to know if this problem has been seen before on other models that have a similar board.

 

[riveracc1]

My radio was fixed today! From what I read it's a common problem on the 2950's, nothing else but a voltage regulator bad. I don't have a clue as to what it powers but I know that on the 2950's there is a mod for higher modulation involving this transistor, Q54- 2SB754. A 5 dollar part that the tech pulled from and old chassis.

A 5 minute repair and all my troubles were gone. Advice I just have for all, NEVER adjust the deadkey while keyed! You key and look, unkey adjust, key look, unkey adjust...

p.s. Thanks for all the replies on how to address my problem