Batboard

is any one having any problems getting a high or low output on pin #4 on a cm300. we are trying to use two tone alerting to throw an output to trigger a page buffer to start it's timing sequence.

Pin 4 is switched to 12v through a transistor, and has a 10k pulldown resistor, so it's more geared towards pulling something high than low. I don't have the specs at the moment but I would guess it's good for 200mA high and about 1mA low.

I have had problems getting an COS active low on pin 4 before on the CM / PM series, I usually use pin 8 with good results.

The CDMs pull pin 4 low through a transistor, why they did the opposite on the CM is anybody's guess.If you really needed an active low on pin 4 you could set it for active high and use it to drive an external transistor.

I got the radio back from motorola today and they said it was a corrupted codeplug that was cause of the problem. They updated the firmware to 03.01.01 and the codeplug version was 04.01. I had another cm300 that was doing the same thing and it came back saying they had to resolder something on the board. it is just weird that i had three radios fail like that. My boss has a cool saying that i like when something goes wrong that you cant explain what is going on he calls it "FM" meening "F*&%^@! Magic" lol
thanks for the help guys!

I thought the CM series had only 4 to 5 volts max om pin 4. I could not get one to work with a rick and a CDM 1250.

JD wrote:I thought the CM series had only 4 to 5 volts max om pin 4. I could not get one to work with a rick and a CDM 1250.

What I stated earlier is based on the schematic in the detailed service manual.