CDM1250 repeating power-on beep, non-functional

nmfire10 · Post by **nmfire10** » Wed Nov 23, 2005 7:30 am

I have a CDM1250 control station in one of our offices. It has developed this condition where it just beeps and doesnt' actually turn on. It just keeps repeating the power-on double beep over and over. Th display never comes on and the radio never does anything else. Unplugging and plugging back in doesn't fix it. What could this be?

thebigphish · Post by **thebigphish** » Wed Nov 23, 2005 8:19 am

i saw a bad codeplug do that to a CDM1550 once...

nmfire10 · Post by **nmfire10** » Wed Nov 23, 2005 9:26 am

It's worked fine for the last year. POS.

jackhackett · Post by **jackhackett** » Wed Nov 23, 2005 10:54 am

There's a part that goes bad that causes that, it's easy to replace, but a bit expensive.. part number is CDM1250 ;)

Seriously though.. I've seen a number of CDMs that wouldn't turn on, but they're usually completely dead, no beeps. If you have another one you could swap control heads to narrow it down. You could also check the power switch, IIRC it should have 5V on one side, the other side switches from around zero to 5 when it's pressed.
The dead ones I've had all went to depot, where they resorted to replacing the above mentioned part.

Nand · Post by **Nand** » Wed Nov 23, 2005 2:52 pm

Simple, just read this section from the manual below on a day that you don’t suffer from a headache already.

The On/Off/Volume knob, when pressed, switches the radio’s voltage regulators on by connecting line ON OFF CONTROL to line UNSW 5V via D0821. Additionally, 5V at the base of digital transistor Q0822 informs the control head’s μP about the pressed knob. The μP asserts pin 62 and line CH REQUEST low to hold the line ON OFF CONTROL at 5V via Q0823 and D0821. The high line ON OFF CONTROL also informs the host radio that the control head’s μP wants to send data via the SBEP bus. When the radio returns a data request message, the μP informs the radio about the pressed knob. If the radio is switched off, the radio’s μP switches it on and vice versa. If the On/Off/ Volume knob is pressed while the radio is on, the software detects a low state on line ON OFF SENSE, the radio is alerted via line ON OFF CONTROL and sends a data request message. The control head μP informs the radio about the pressed knob and the radio’s μP switches the radio off.

Nand.

thebigphish · Post by **thebigphish** » Wed Nov 23, 2005 8:28 pm

great. another obfuscated description about a hideous logic gate on off control. What ever happened to a SPST?

jim · Post by **jim** » Wed Nov 23, 2005 9:10 pm

All I know is that I've seen a pile of them so this and they all were depoted and had new processors installed.

nmfire10 · Post by **nmfire10** » Wed Nov 23, 2005 9:20 pm

OK. So basicly it's a doorstop and needs to go out, nothing I can do for it. Figured.

xxx2fan · Post by **xxx2fan** » Sat Dec 10, 2005 6:14 pm

I had this happen to my cdm1250 vol. fire dept radio.

/\/\ picked it up and it had bad part in radio was covered under warranty they fixed it at local shop had to order the part though so you may need radio repair to take a look at it.

n5tbu · Post by **n5tbu** » Sat Dec 10, 2005 7:55 pm

lol@Nand! moto can sure be funny.
mod

nmfire10 · Post by **nmfire10** » Sun Dec 11, 2005 6:09 am

Nand wrote:Simple, just read this section from the manual below on a day that you don’t suffer from a headache already.

Blah blah blah blah blah blah

Remember when turning the knob to [off] used to just disconnect the power?

jackhackett · Post by **jackhackett** » Sun Dec 11, 2005 12:26 pm

nmfire10 wrote: Remember when turning the knob to [off] used to just disconnect the power?

Yes, but put yourself in the position of a Moto engineer, 6 months to design a circuit that turns on the radio based on data collected by 3 processors and a couple of DSPs about the relative proximity of the user's finger to the knob, the current position of the planets and the phase of the moon, or 5 seconds to say 'put a switch in the power lead'. Which one gets you that new BMW?

n1pfc · Post by **n1pfc** » Sun Dec 11, 2005 2:01 pm

jackhackett wrote:
nmfire10 wrote: Remember when turning the knob to [off] used to just disconnect the power?
Yes, but put yourself in the position of a Moto engineer, 6 months to design a circuit that turns on the radio based on data collected by 3 processors and a couple of DSPs about the relative proximity of the user's finger to the knob, the current position of the planets and the phase of the moon, or 5 seconds to say 'put a switch in the power lead'. Which one gets you that new BMW?

none, you have to work for CML to get that

compuman81 · Post by **compuman81** » Mon Dec 12, 2005 1:34 am

something interesting...

tonight I took a ribless cable I had bought years ago for my ht1250 (before I ever bothered to make my own cables

) and I added another cable coming from the serial dongle that will program maxtrac/radius/cdms ( a small modification I had to make), and I needed a way to power the circuit inside (contains 5 volt reg) which is normally powered off the accessory connector on the 1250 that puts out 7.5 volts, ( the 5 volts is required to run the logic chip in the rib in the dongle), so I drilled a hole on the 1250 end of the cable in the back, and now I have a 9 volt battery connector that I can plug in a battery to program the mobiles. Before doing this i tested the cable by covering up the RX/TX pins on the ht1250 , not ground and power, and used the battery power from the ht1250 to power the rib in the dongle to program the mobile at the same time haha

anyways, after I did all this, while i was experimenting, both my radios started rebooting like this, beep beep, repeatedly like they kept booting with this rib cable connected. I removed the cable and both the portable and mobile boot up fine. Its strange how the portable was affected due to the fact It only had the power pins connected...but regardless they did the same exact thing, and now that I dont need to connect the portable to program the mobile ( using the battery ), the mobile still does at times ( cdm1250).... so you if you're gonna start trying to fix the radio and can't replace the control head, this is the place to start, maybe...

nmfire10 · Post by **nmfire10** » Mon Dec 12, 2005 7:31 am

/\/\SS came in and took it away. I look forward to seeing what the results are.

doctahvms · Post by **doctahvms** » Mon Dec 12, 2005 10:41 am

I had this problem - it was the control head board (or specifically the uP). If you can find a CDM1250 head to try - I think you'll find it fixes it.

d

Hightower · Post by **Hightower** » Mon Dec 12, 2005 12:26 pm

A shorted mic can cause this. Did you try remving the mic and see if the radio powers up?

nmfire10 · Post by **nmfire10** » Sat Dec 17, 2005 6:36 am

Just came back from MSS yesterday. It visited the Depot and came back unprogrammed of course.

CDM1250 repeating power-on beep, non-functional

CDM1250 repeating power-on beep, non-functional

cdm1250 turning on and off