CDM750/1250

[jims123]

We have been sending our CDM 750 & 1250 radios to Motorola for a problem that has haunted this model of radios for a long time. The problem is that the radios will lock-up in EEPROM or BOOT Enable. Motorola has replaced the main board on every unit we have send at a cost of over $270.00 each We have also found that great RSS up-dates have not worked at all to solve this issue in the field, and some radios have been back to Motorola more that two times for the same issue. And yes. a11 have power and all requirements to function and operate correctly. Ignition issue from Q641 to Q0661 also R 0661 are clean. if there other areas have I missed something??

[35echo]

jims123,

Check U101 pin 90 and see what the frequency of the signal is.
If it is 3.6864Mhz the micro is not completing the startup sequence and U121 (FLASHROM) is probaly the issue. Check U121 pin 30 for a repeating square wave type signal. If it is there then the micro is polling the flashrom for data and either not getting it or what it is getting is corrupt. You have to be able to program new ones and have a hot air rework system to change these. One other thing to check is for shorts between adjacent pins on the address and data lines on U101 (Micro), U121 (Flashrom), and U122 (Static RAM).

If it is 7.3728Mhz or 14.7456Mhz then the micro startup is complete and more info/troubleshooting is needed.

Regards,

Allen

[jims123]

I will check this Thank You!