Recent content by b2cooll

I would say it's from the mixers maybe one of the IF's is to strong & overloading the mixer or notch filter as those are a add/subtract kind of thing. Thats a guess as I am thinking the DDS replaces one of the IF's. These maiboards have the same offset on AM & USB with LSB being 3kc lower...

That is odd for sure, I have seen transistors get noisy but 9S is very odd. If the RF gain takes it out then you have to work backwards from there, so maybe pull the pass thru cap between stages until it's gone. Now knowing you my friend... you have a DDS setup in that rig to get more channels...

Thanks for the detailed message, I have 6 of these radios and they all do the same thing... after sitting idle for 10 min I press mic and No RF output on AM or SSB. yet when 1st turned on AM and SSB work fine, 4W AM 12W SSB I do not this this is a driver or AM regulator issue as the...

Bummer James, I have a 5555n and with the power knob fully CCW it has 2.5W and poor forward mod to 4W with the knob full CW it has 9W with nice forward mod to 16W AM, these rigs can blow up amps easy, the SSB swing is 30W and the knob is touchy, but love my 5555n hate the mic but love how you...

Very good Info, "thanks" the pictures I showed were from a different rig. I have been working on a base station, but opened up a mobile version to show some pictures, and that one has not been touched yet. And yes I do so many places that could cause bad contacts, intermittent working and...

Nice reply, "Thank you" and did I hear the word DUT :^) a common term used in my calibration background. Really this is a very detailed and thought out observation with some good suspects to look over. I will go thru this CB and measure, measure and measure some more to tackle this...

Anyone out here have a working CB555, that will TX for more than 10 mins :^)

I will post a picture of the schematic / finals where you can see there is no bias adjustments, Really my troubleshooting has led me to some type of coupling or decoupling of the RF signal An odd radio, I am not aware of this chassis being used in any other radio. no help on the web...

Shoot, with my multiple units all sharing the same fault, I thought for sure there was a known fix for these Motorola CB555 rigs... they are nice and when working as kind of special as they use a true Motorola design. Worth fixing.

Good Memory... you are right, I called it a condenser DOH but it is a dynamic mic with a built in pre-amp, no battery as it is powered by the radio.

Thanks for that Info, I do have a copy of that, I will post a picture of the finals. I do not see any Bias adjustments and the manual does not speak of any bias adj there. The final is a C1817 so my experience with that is limited, The mixer has a couple of electrolytic and I replaced...

Posted Pictures, and I just want to say thanks again, Their just is no info on this mainboard anyplace. They are nice rigs, very good specs and a nice look, need to find a fix > See attached pictures of the mainboard these are double sided and that makes troubleshooting harder, yet I can...

Thanks for the feedback, I will offer some more details as I have a good 40 years of repair experience, just retired at Fluke and love working on these old rigs. These do have a odd mic, a condenser if I remember powered by the radio and they tend to get damaged. I have a good mic on mine...

Thanks Retro, yeah I have a few Motorola SSB CB rigs, they all do the same thing. After 5 min, the TX just fades away to milliwatts. I thought it was a heat issue but cold spray would not confirm that. But leave the radio off for 5 mins and it works again, for a couple of mins. I have...