Baron Very low TX

[95yjdave]

Good morning list,

I purchased a Baron on marketplace for relative cheap.  I was advised ahead of time it was not " working " .  Purchased anyway hoping it would be something easy to repair.  Got it out of the box. It powers up fine.  RX is good.  Key up the mic on AM.  And here is where the fun begins.  It keys up.  but only a 1/8 of one watt or less.   I watch the 3 way meter.  It starts to key up.  Then drops to almost nothing.  I can hear slight modulation from another radio on the table.  Switch to SSB.  It keys up to maybe 1/2 of one watt.  I recapped every electrolytic capacitor.  Trying to research this model (  as with Cobra 132 xlr ) did not provide much info.  Except that this could be a difficult radio to repair.  I am not a tech.  But possess very basic diagnostic skills.  My component replacement skills are at expert SMT level.  ( 11 years at Motorola Cellular Infrastructure as a analyzers personal component repair assistant - He analyzed, Then passed the boards to me for parts replacement . )  I do not yet have a Sams Photofact.  That will be coming soon.  So...  Being I am at the very infancy of this repair.  Is there a solution that sounds familiar given what I describe ?   Thanks.  Dave 

[Sandbagger]

Jan 1, 2023 9:30:38 GMT -5 95yjdave said:

Good morning list,

I purchased a Baron on marketplace for relative cheap.  I was advised ahead of time it was not " working " .  Purchased anyway hoping it would be something easy to repair.  Got it out of the box. It powers up fine.  RX is good.  Key up the mic on AM.  And here is where the fun begins.  It keys up.  but only a 1/8 of one watt or less.   I watch the 3 way meter.  It starts to key up.  Then drops to almost nothing.  I can hear slight modulation from another radio on the table.  Switch to SSB.  It keys up to maybe 1/2 of one watt.  I recapped every electrolytic capacitor.  Trying to research this model (  as with Cobra 132 xlr ) did not provide much info.  Except that this could be a difficult radio to repair.  I am not a tech.  But possess very basic diagnostic skills.  My component replacement skills are at expert SMT level.  ( 11 years at Motorola Cellular Infrastructure as a analyzers personal component repair assistant - He analyzed, Then passed the boards to me for parts replacement . )  I do not yet have a Sams Photofact.  That will be coming soon.  So...  Being I am at the very infancy of this repair.  Is there a solution that sounds familiar given what I describe ?   Thanks.  Dave 

Well, the most common failure that would cause what you are seeing, is a blown final output (or possibly the driver) transistor. Of course there could be other issues as well, including a "golden screwdriver" alignment. But if the alignment looks good, I would start with the final and go from there.

[2600]

A 'scope with a times ten probe is your best friend here. The final and driver transistors will each have one leg soldered to a ground foil. This is the emitter. The opposite-side lead is the base. Center lead is the output side, collector.

The RF voltage at the base should be at least five times less than the RF peak-to-peak voltage on the collector. A bad driver or final's collector side will show only DC and audio voltage, with very little RF riding on it, compared to the input drive level.

And if you don't have access to a 'scope, that makes it trickier.

73