In my opinion, having been a electronic tech in my past life, I think
you have either a cold solder connection, a crack in the PCB, or a loose
connection on a jumper cable. Or a combination of them all. Likely
near a pressure point. I.E. the push button and where the board is
tightened.
Dan/W4NTI
Mike and Alicia Fanning wrote:
> I am having a really bizarre problem with my recently purchased used Mark V
> Field. When I bought the rig, the noise blanker button was intermittent -
> that is, you had to hit it several times to engage or disengage the noise
> blanker (no beep and no LED toggle). I just bought the roofing filter mod
> and some CW filters from Inrad, and while I was installing the mod, I
> decided to fold down the front panel and see if there was anything obviously
> wrong with the PC board assembly that houses the NB button. I checked
> continuity on the button, and electrically everything seems fine. I then
> powered up the radio (with the front panel still loose), and as I am folding
> in the front panel to screw it back into place, the NB button works perfect
> until just before the panel reaches vertical. If I tilt the front panel
> just a few degrees outward, all is well again. I have tried this same
> experiment with no power applied and a multimeter checking the continuity of
> the NB button while holding down the button, and the switch always seems to
> make good closure, no matter what the position of the front panel assembly.
> However, when I power it back up, same story as before - just before you get
> the panel vertical, the NB button quits working. I unscrewed the two
> "hinge" screws at the base of the front panel assembly, kept the front panel
> vertical, and moved it slightly backward and forward (closer and farther to
> the chassis). Again, the NB button quit working when I got within close
> proximity of the chassis.
>
> There is a pc board of some variety with a metal can around it that resides
> right behind the NB and filter selection buttons, approximately 3-4 inches
> tall and about an inch wide. I am guessing this is the shield for the high
> voltage power supply that runs the front panel display. My current theory
> is EMI getting into a control line and corrupting the pushbutton data, but
> at this point, I am out of airspeed, altitude, and ideas.
>
> Has anyone else seen this behavior? Can anyone offer some helpful tips?
>
> Still scratching my head,
> Mike, K4GU
> _______________________________________________
> SECC mailing list
> SECC at contesting.com
> http://lists.contesting.com/mailman/listinfo/secc
>
>
>
--
No virus found in this outgoing message.
Checked by AVG Free Edition.
Version: 7.1.394 / Virus Database: 268.10.7/409 - Release Date: 8/4/2006
|