cdm series... wont power up.

[steve220]

I have on my bench 2 cdm1250 UHF mobiles. Both exhibit the sane symptoms..... no power up. When hooked to a power supply I can see that when the power button is pressed the unit starts to go thru the power up sequence but does not pass the self test. Radio will draw stand-by current of about 190 ma until power is disconnected. Pressing the power switch has no effect .... unit remains "on". When in this state it has no display, no beeps and no response from any keypress. Can't read or write to the codeplug. This seems like a common problem for the cdm series, I know I've sent a number of radios to the depot for this issue. They just replace the board and call it a day. I'm tired of the flat rate repair charge for what should be a fix for a common issue. So far I have checked various switching circuits and the 16.8 mhz reference oscillator..... all are normal. I'm scratching my head now. Anyone have any ideas ? Thanks Steve.

[escomm]

Radio is not programmed for ignition sense, is it? Do you have 12V running to pin 10?

[steve220]

No ignition control is (was) programmed. I'm still poking around for a voltage measurement that's not right.
Steve

[35echo]

Steve,

Most of the CDM's we see with this problem have a bad flashrom. Especially if it has an Atmel AT49F040 for U121.
We replace them with Atmel AT49BV040B which is what Moto uses on the new boards and it fixes the problem.

Regards,

Allen

[Wile E. Coyote]

Steve,

Most of the CDM's we see with this problem have a bad flashrom. Especially if it has an Atmel AT49F040 for U121.
We replace them with Atmel AT49BV040B which is what Moto uses on the new boards and it fixes the problem.

Regards,

Allen

So if you simply purchase an Atmel AT49BV040B and replace the chips, will the CPS still work out of the box, or do you need to pre-flash them with a codeplug?

I only ask because I have a small pile of radios with this problem. I have been able to get them running again by swapping in a good U121 from a water-damged radios.


-WEC

[RADIOMAN2002]

Havn't done it so can say for sure, but chances are you will need Lab or Depot to re-enable the radios firmware.

[35echo]

Wile,

You have to pre-load the firmware before you reflow the chip in place. This is not the codeplug
but the firmware. You have to use the correct core file combined with the Tanapa specific file to build
the firmware file then use a programmer to program this file into the flashrom. You also have to pay
attention to the codeplug version / firmware version to make sure they are compatible.
Also the formatting of the firmware varies between 1,2, and 4 meg flashroms.

Regards,

Allen

[steve220]

Hello All,

I'm still banging my head against my bench with these things.
I replaced the flash eeprom and thought that reloading the firmware using a standard upgrade tool would reload the operating system ..... no go. I'll have to go back into this.

Another radio had a bad micro .... changing it allowed me to reprogram the firmware but nothing further. The micro never completes the start up. (ASFIC synthesizer stays At 3.68 Mhz).

I've wasted hours on these things ..... now its a matter of beating the broken radio.

Steve

[Wile E. Coyote]

Thanks 35echo. For a second there I thought it was going to be complicated

Okay, so maybe it is a little over my head. I don't think I can justify purchasing an eeprom burner just to hopefully get a few radios going again. Although part of me would love to do it anyway just to say I did it. Thanks for the info!

-WEC

[com501]

I'm collecting a box of radios I can't sell or are broken for Emcomm West. We are going to use my machine gun (haven't decide which one yet) on them on the weekend.

Contributions are always welcome. Bring your own digicam.

This would be a fitting end for those 1250's, since they aren't worth flat rating.