MSF 5000 int TX problem

[BJMCDANIEL]

First, I am a GE kinda guy, and I don't know Moto as well as I should. But I have been running an MSF5000 at 443 for several years. This is the older model that requires the R1800 to program. The TX has become intermittent. If it is keyed manually at the site, or via the input and it has gone dead/quiet, approximately, 5 seconds after kerchunking it, the TX will key up for a single short burst. It will work normally for weeks, then going to sleep for <24 hrs, and it wakes back up. Resetting the PS will not make a difference. The site is reasonably controlled as far as temp goes.

Tnx de KE5PL

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[bernie]

My two bits worth:
Intermittent problems are difficult to trouble shoot from an island, but here are a couple of possibilities:
Capacitors:
the 5V cap on the control board often fails. this is the funny looking one
with 3 leads. the lead on the top of the case is for support. Red epoxy on the end. Replace it with one from the parts store, not the original. there is also one of these on the interconnect board on the bottom of the RF casting. these cause the station to go into reset.
1,000Uf 16V
The big capacitors in the 13V power supply can cause a problem if they de-rate. The A+ drops enough to cause the station to go into reset on PTT.
Another problem is if the power is set too high the station can go into low power (protect mode) when the PA gets hot. Not likely the problem.

Another problem is that the solder can burn on the output circulator in the PA.

Last, but not least, one of the VCOs could be going out of lock.
Hope that this helps,
aloha, Bernie KH6IAH

[n9upc]

W ehad the same problem with a local law enforcement dept. over here by me and it turned out to be the ant relay in the MSF. It is a pain in the a#@ to get to also. You almost have to go and shut the station down and then reach in an unscrew it.

Baffled us for a couple of weeks as the same problem you described was happening. Our symptoms were under normal use was ok but then if there was any transmission that last over 30 seconds it was a slow downward race to it shutting down and not switching for about a day and then it would come back like there was no problem.

Hope this helps????