run-acc or run-start for turn-on lead?

eboe · Post by **eboe** » Thu Feb 17, 2005 8:18 pm

ok, i'm just curious what everybody else is doing. thus far, i've been using circuits that are hot when the key is in the run position or the accessory position (run-acc) for the radio's turn-on lead. is it better or worse to use a circuit that's hot while cranking (run-start)? i haven't had any trouble, but i think i remember hearing that one way is good while the other might freak out the radio where it doesn't know whether to turn on or off. which way is better?

thebigphish · Post by **thebigphish** » Thu Feb 17, 2005 8:22 pm

I like the "off while cranking" position if i have to do a IGN switched system. I don't even want to think about the undervolt and the current surge of a car w/ that hi-torque motor is cranking away under the hood.

nmfire10 · Post by **nmfire10** » Thu Feb 17, 2005 8:29 pm

Ditto.

kb0nly · Post by **kb0nly** » Thu Feb 17, 2005 9:02 pm

ditto from me too!

The last thing you want is to spike your radio when the starter is running. That's why all the car stereos turn off while cranking, the manufacturers recognized this problem many moons ago.

Usually to make it quick and easy i use the switched power for the car stereo to run a relay to turn power on and off to the radios ign sense lead.

Then your radios behave like the car stereo, on with the key in the on or acc position, but off while cranking, and right back on after the engine starts and you stop cranking.

MassFD · Post by **MassFD** » Fri Feb 18, 2005 9:01 am

I have had problems with the CDM Series using the "off with Crank" connection. Radios are wired with the power connection directly to the battery, only the igniton lead (pin10) is switched

Problem only shows in Diesel Ambulances, key on while wating for glow plugs to heat powers up the radios. After the wait to start light goes out you turn the key to start, this drops the pin 10 power to the radios.

When the engine starts you release the key and the power is returned to the radio, some times it will power up - sometimes not. It's a timing issue with removing and re-applying power within a short time.

Moved the pin 10 power to a source that is hot during crank and the problem went away. I do not like the idea of the radio seeing the spike created by the starter either but if you look at it with the MAIN POWER connected directly it sees the spike anyway.

On our larger trucks the Main Power comes from the battery and Pin 10 comes from the Master Switch so they have been seeing this spike (from a much larger starter) for years without any ill effects.

My vote is on during crank

Mobilelect · Post by **Mobilelect** » Fri Feb 18, 2005 4:56 pm

CDM installs in ambulances need to have radio main power connected to key operated relay output supplied by the conversion company or make one yourself. Jump pins #7 & 9 on accessory connector on the back of the chassis. No need for ignition sense kit or connection. to #10. Have 30+ EMS units & 60+ Fire units connected this way. Works great. Peter

MassFD · Post by **MassFD** » Fri Feb 18, 2005 6:17 pm

How does jumping 7 (ground) to 9 (emergency switch) turn the radio on. I have also found that removing the power from the main feed sometimes causes the radio to power up on a random channel instead of where it was shut down.

It apears that the low bands act diffrently than uhf on power cycle, I never have problem with low band only uhf

Mobilelect · Post by **Mobilelect** » Fri Feb 18, 2005 8:16 pm

Jumping pins 7 & 9, 7 being ground and 9 is for an emergency switch to turn radio on without ignition sense. The Warius mobiles are flaky on reboot. Several firmware upgrades ago the time delay turn on and off was increased to over shadow the flakiness. By grounding pin 9 and applying power to main cable the radio boots perfectly and is in the last state it shut off in. Peter

Mobilelect · Post by **Mobilelect** » Fri Feb 18, 2005 8:27 pm

I have noticed early on with the installs rthat some models were more prone than others to that boot mess. Like I stated once I jumped 7&9 the problem was gone. I went back and installed the jumper in the previous installs. We have lows, vhfs & uhfs. About nine or ten have R*I*C*K s connected and those I jumped 7&9 right on the RICK board for both radios. Peter

MassFD · Post by **MassFD** » Fri Feb 18, 2005 8:33 pm

I will have to try the 7 to 9 jumper. Would not have guessed that holding the emergency switch low would cause the radio to boot with out a pin 10 high.

Got to try it, most of the installs I do could go without Ignition sense if that works

thebigphish · Post by **thebigphish** » Fri Feb 18, 2005 9:26 pm

the CDM for us has always been a strange bird anyways...i posted a while back about a problem we were having with an undervolt actually locking the unit up....when the unit was set up to follow IGN, an undervolt would actually make it behave the opposite of what it was supposed to be doing. The buss would go to about 11 volts for a couple of seconds and the radio would stay on., and as soon as it recovered to a healthy 13.4 the radio would shut off. I'm pretty sure these were early model CDMs, as they problem has more or less been isolated to our older units, but it was a pain to deal with.

It was quite annoying, as the radio would be set to "On/Off & Ign" yet you would be incapable of changing the state. The undervoltage would make the radio barf and all of a sudden you couldn't turn it On if it was off and vice versa. Some other bizzarro problems followed that, like a PTT that would not work or you could not change the channel/tkgroup. It has been a while since we've seen that stuff, as the units have been refurb'd and changed, so it leads me to believe it was a pretty isolated, early model issue.

giguchan · Post by **giguchan** » Sun Feb 20, 2005 3:43 pm

Just as i thought this was getting easier...
those cdm's... whats wrong with a single#6 from the hood to a block and then connect them from there.. btw whats a good breaker to use? and block?..
all i have is the 2 cdm's.
thanks..

MassFD · Post by **MassFD** » Tue Feb 22, 2005 1:30 pm

Just got around to trying the 7 to 9 jumper. It did not allow the radio to power up without a pin 10 ignition lead.

Like I said before, I do not see how puting a ground on the emergency switch will cause the radio to power up with only the main battery cable connected.

thebigphish · Post by **thebigphish** » Tue Feb 22, 2005 2:09 pm

i'm as confused as you are, i tried this and didn't have any luck either...maybe there is something that i'm missing, or maybe not. Either way, grounding the emerg. pin to 7 doesn't even SEEM like it would do what we want it to.

Mobilelect · Post by **Mobilelect** » Fri Feb 25, 2005 4:05 pm

Recheck accessory configuration set to on/off ignition sense, boot down with front button after program change. Now radio will boot with out pin 10. apply main power radio will boot ( may have to push front button firt time on some units. Now toggle power on main cable. depening on firmware radio may take a second to boot. Boot off connect &&9 radio will boot each time When connecting 7 & 9, forget pin 10, post your results. I will send you a codeplog if needed. As I posted above I got lots of them all wired and work this way. Peter