DAK CB BUT NO MODULATION HELP!

[darticus]

I bought a radio that seems to do everything right but has NO modulation. Recieves good, power out good 5w, but No modulation. No hum buzz when I touch the audio pin on mic socket. Tubes check good, bypassed the mic gain control but no hum when touching connections. This is a DAK CB with transistor receive and tube transmit. ANY Thoughts? There are 3 - 47microfarad caps that I'm questioning but can't test and don't have any to try. see schematic pic. Email me for schematic [e-mail] Thanks Ron

[Sandbagger]

Nov 15, 2012 8:20:22 GMT -5 darticus said:

I bought a radio that seems to do everything right but has NO modulation. Recieves good, power out good 5w, but No modulation. No hum buzz when I touch the audio pin on mic socket. Tubes check good, bypassed the mic gain control but no hum when touching connections. This is a DAK CB with transistor receive and tube transmit. ANY Thoughts? There are 3 - 47microfarad caps that I'm questioning but can't test and don't have any to try. see schematic pic. Email me for schematic [e-mail] Thanks Ron

Well, the problem is that it could be many things. One thing that is a common issue with those DAK MK X's is the audio modulator being a bit underrated for the job, especially if you clip the modulation limiters out. I would check the modulation output transistors and other associated parts. You will need a good voltmeter, an audio signal generator and a scope to signal trace and do a thorough job.