GP300 only transmits when held horizontal!

[karlschneider]

I got my hands on a P94 8 ch 300 that receives perfectly and programs tx & rx fine. If I hold it upright, it usually won't transmit but if I hold down the PTT and tilt it down to near horizontal, it suddenly has output. Thumping (gently of course) on the case when it's upright will cause it to send out some naughty noises on the selected frequency (holding PTT down)

I've had it out of the case 5 times, looking for loose connections and inspecting solder joints but so far I can't see anything
awry. Just wondering if there is some specific place I should be looking...I don't have any schematics or manuals at all...

Oh I just discovered something - when it appears to have no transmit output, (doesn't active my counter a couple feet away),
it IS apparently generating RF on the proper channel, I can hear it on a receiver across the room. Can't believe I didn't try this before...but it's obviously very LOW...not even perfect quieting that close...so I guess the PA is intermittent. Argh. I gotta get a book for this critter.

[Tom in D.C.]

Karl,

Start by yanking the chassis and checking the solder joint(s) for the
antenna connector. If that's not it then you could rig up a method
to connect power to the bare chassis and start pushing on the boards
to see where the break is.

I've seen cold solder joints that have shown up years after the equipment
was put into service and was working okay...for a while.

[a_j_b]

The pencil eraser on a #2 pencil works pretty good for pushing on components.