VHF CDM1250 Tuning Woes

d119 · Post by **d119** » Sat Dec 23, 2006 2:51 pm

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.

d119 · Post by **d119** » Sun Dec 24, 2006 4:34 pm

No help?

ve3nsv · Post by **ve3nsv** » Mon Dec 25, 2006 12:24 pm

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.

d119 · Post by **d119** » Tue Dec 26, 2006 11:47 am

Interesting. I'll try it again once I get to the shop tomorrow. Thanks for the suggestion.

d119 · Post by **d119** » Wed Dec 27, 2006 8:12 pm

No dice. Tried it after it sat for a week, and it's still being a pain.