this is very strange, and i am now more confused than ever.
there are a few possibilities for why you would have continuity from PC board ground to chassis ground.
the most common places are going to be the places where there is a metal part that bolts to the chassis that contains PC board ground connections bypassed by disc caps.
these would be the mic jack, the external speaker or pa speaker jacks, the power plug, and any IC, transistor, or other component that is bolted to the chassis.
the transistor thing may be a long shot, but i guess if you had a transistor that was shorted collector to emitter, and then the collector tab was touching the chassis, then you could get this issue.
Usually when i come upon a problem like this, i have to remind myself to go back and thoroughly check all the places that IM SURE it's not.
that switch that is hard to get to, or involves taking the face plate off yet again, the board that requires unsoldering 20 connections to take it loose, etc...
remember that depending on your antenna, it may be a DC short. if you have an antron 99 or an IMAX, and you were to put your ohm meter right at the SO-239 connector on the base of it, you would see a DC short. that's how these antennas are.
so, if that's the case, then plugging in the antenna is creating that connection between chassis and PC board ground.
it's time to stop guessing and start with a systematic approach.
disconnect everything that is mounted to the chassis one by one and check for continuity in between each part.
im afraid this one is all up to you at this point, as you are the only one who will be able to see the results of your tests.
just don't assume it's not something you already checked.
if you have a connection between PC board ground and chassis ground with the radio off, power plug unplugged, and no antenna connected, then start there and you won't need to power up the radio or hook anything up to find your problem.
good luck!
LC
there are a few possibilities for why you would have continuity from PC board ground to chassis ground.
the most common places are going to be the places where there is a metal part that bolts to the chassis that contains PC board ground connections bypassed by disc caps.
these would be the mic jack, the external speaker or pa speaker jacks, the power plug, and any IC, transistor, or other component that is bolted to the chassis.
the transistor thing may be a long shot, but i guess if you had a transistor that was shorted collector to emitter, and then the collector tab was touching the chassis, then you could get this issue.
Usually when i come upon a problem like this, i have to remind myself to go back and thoroughly check all the places that IM SURE it's not.
that switch that is hard to get to, or involves taking the face plate off yet again, the board that requires unsoldering 20 connections to take it loose, etc...
remember that depending on your antenna, it may be a DC short. if you have an antron 99 or an IMAX, and you were to put your ohm meter right at the SO-239 connector on the base of it, you would see a DC short. that's how these antennas are.
so, if that's the case, then plugging in the antenna is creating that connection between chassis and PC board ground.
it's time to stop guessing and start with a systematic approach.
disconnect everything that is mounted to the chassis one by one and check for continuity in between each part.
im afraid this one is all up to you at this point, as you are the only one who will be able to see the results of your tests.
just don't assume it's not something you already checked.
if you have a connection between PC board ground and chassis ground with the radio off, power plug unplugged, and no antenna connected, then start there and you won't need to power up the radio or hook anything up to find your problem.
good luck!
LC
