UHF digital MSF troubleshooting questions...

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batdude
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UHF digital MSF troubleshooting questions...

Post by batdude »

i have a buddy's GMRS UHF digital shelf over here.

wierd problem.


when you plug in the station, you get the green light on the power supply, the station control boots up, and starts spitting out all kinds of errors... E41, E41, E49 (some of these aren't even in the big fat thick service manual that i *DO* actually have for UHF stations....)

anyway

my initial once over of the station indicated that the 26pin ribbon cable that runs from the interconnect board to the SCCB was absolutely MUSHED when some (#@@(# individual tightened down the screws on the RF tray cover...this cable connects to J801 on the SCCB...carries all kinds of interesting signals... steering voltages, etc.

well, i replaced said cable with the identical one from my VHF (they are both wired straight thru) and ....

NO CHANGE in station operation at all.

I read the station with RSS, and changed some of the operating parameters (squelch type, etc...) mainly just to ensure the SCCB was indeed capable of communicating with the outside world... and again, no dice after reprogramming...

right now, i do not get any VCO indications, and the PA KEY light is barely lit - just enough so you can tell it's actually conducting - but indeed, it's "ON"..... (the station is not keying however)

my initial thoughts were the DC-DC converter section.... but this checks out ok from the troubleshooting chart in the book....

anyone wanna take a stab with one of those "YEAH, I SAW THAT" type messages?

**UPDATE** - there is no 9.6vdc from the iPA.... and there's charred components on the iPA.... guess that solves this one.

anyone (other than Panik) have a spare UHF IPA?

doug
bernie
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Post by bernie »

My two bits worth:
DO NOT OPERATE THE STATION WITH OUT 9.6 V PRESENT.
Otherwise you will have the 5v regulator on the control board to rebuild.

The 9.6 is the reference for the 5V switcher, and the switch transistor will fail, possibly also the driver.
There are two versions of the 9.6V regulator on the IPA module.
Aloha, Bernie
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Doug
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Post by Doug »

Hey Doug,
E41 = TX loop ctrl line not changing states
*Probable cause = Tx loop signal is not toggling as expected, idicating a bad transmitter synthesizer
* Corrective action = Replace uniboard
E49 = Rx Loop (Same as above just on the recieve side)
As a side note my manuel has 23 pages(yes 23) of just error codes and their definitions
Later...
Doug
May the Schwarz be with you.
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