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VHF CDM1250 Tuning Woes

Posted: Sat Dec 23, 2006 2:51 pm
by d119
Hi Group,

I found a CDM1250 VHF radio with no control head on it at work, so I pieced it together and essentially have a complete VHF radio.

Receives great, but NO POWER OUT.

I work for an MSS, and I went through and upgraded the firmware to R05.04.01, and followed the procedures in Tuner and set the PA Bias Voltage, and set the K & M tuning and all of that.

When I get to the "PA Limiter Voltage" AUTO-TUNE screen, and I do the auto-tune, it errors out and says "Check Hardware". The help screens offer no information other than "This means Tuner could not set the softpot values".

Any thoughts on how to get this working? It's driving me nuts, and could be a completely usable radio if I could get it to transmit.

Power is ~20w on the test channels when doing the K&M tuning for the high power mode, and ~1.5w on low power mode.

Help appreciated. I've never worked on CDM radios before... I usually work on ASTRO and JEDI products.

Posted: Sun Dec 24, 2006 4:34 pm
by d119
No help?

Posted: Mon Dec 25, 2006 12:24 pm
by ve3nsv
I had a CDM1550LS+ that had this exact same problem, I unhooked it and let it sit for a few weeks while I worked on more pressing issues and when I tried again weeks later it tuned fine and came back to life.

Posted: Tue Dec 26, 2006 11:47 am
by d119
Interesting. I'll try it again once I get to the shop tomorrow. Thanks for the suggestion.

Posted: Wed Dec 27, 2006 8:12 pm
by d119
No dice. Tried it after it sat for a week, and it's still being a pain.