SP50 no transmit

[radioservice]

So, you say you've got a Motorola Sp 50 that has no transmit power? NO, I've got a half a dozen SP 50 radios that have no rf power out. Changing the final amp has not made a difference. The collector voltage is present. PTT appears to be present. I was hoping that some one on this forum has seen this problem before and may have a good fix.

I Appreciate your response

Bill Erickson
Radio Service, Inc.
http://www.radioserviceonline.com

[kf4sqb]

Check the solder joints where the antenna connector attach to the board. They are a known problem area. I have also seen more than a few of the coils in the tuned circuits around the antenna connector with bad solder joints.

[radioservice]

Thank you...I'll check that....I should have also mentioned that very little current is drawn during TX. Would that symptom indicate bad solder joints in the coils around the final?

[llu727]

Also check the solder connections on the 0.1 Ohm resistor that is directly under the freq slelect switch on the top of the board... Many have become unsoldered/broken. That directly feeds the PA - will have voltage when not keyed.

BJ