x9000 head won't turn on in the cold

walt10 · Post by **walt10** » Mon Dec 01, 2003 7:27 pm

Hello x9000 operators.
I have one that does not like to wake up when it is cold (40 deg F or lower) After the truck warms up a bit it will say system check but still wont wake up. A bit warmer and it wakes up and works fine. Seems to be something with the cpu????
Thanks Walt

natedog224 · Post by **natedog224** » Mon Dec 01, 2003 11:36 pm

Buy some freezespray and start icing over parts after its warmed up. Then press a key and see if its non responsive. Quickest way to find temp problems.

Might be the oscillator for the microcontroller clock. That would do it.

chipjumper · Post by **chipjumper** » Tue Dec 02, 2003 6:16 am

What is the usable temp range for a X9000??

ISPTECH · Post by **ISPTECH** » Tue Dec 02, 2003 7:54 pm

There was a tech note published by Motorola about the 9000 head when used on a Spectra would not power up in the cold weather. The Micro in the head was powering up faster than the radio. The solution was to add a cap in the head to slow the heads power up process down. I have used this mod on several units and it works. The only thing you will notice is the head will take a little longer to wake up. I can get you the info tomorrow if you like.

Post by Pj » Tue Dec 02, 2003 8:52 pm

The only problem in the cold I had was with my old VHf x9000. It wouldn't lock on TX and would hear a buzzing thru the speaker. This only happened on realllllly cold days. When it was really hot out, I think it pulled extra amps. I must have had a California version of the x9000 that only liked 72 and sunny.

walt10 · Post by **walt10** » Wed Dec 10, 2003 2:26 pm

Well Nate... I brought it into the shop. I tacked 12v to the power swithch and went at it with the freeze spray. I found C6 on the HLN 4907 (cpu) Board would open when it was cold. I replaced it and now I can not make it fail again. When I get home I will look up what C6 does in the circuit.
Thanks To all for input.
73 Walt

Forgot I had a Spectra Manual here at work. Looks like C6 is in the Reset Circuit.. No wonder it would not start up.....
Walt

Mike B · Post by **Mike B** » Wed Dec 10, 2003 3:47 pm

C6 is the infamous Watchdog Timer capacitor.
http://www.open.org/~blenderm/syntorx/c ... ml#ch_trbl

Since your C6 was on its way to failing, I would do a preventative maintenance (PM) check and inspect all the other control head electrolytic capacitor(s) for any leakage. When these capacitors finally die, they usually leak which will eventually eat away the PC board traces.

If it was not for the value of C6 being critical, we would probably never know the capacitors were leaking until after a vital PC board trace was destroyed. So, a failed C6 can actually do us a favor by reminding us to do the PM. A nasty sort of favor, but still a favor

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x9000 head won't turn on in the cold

x9000 head won't turn on in the cold

X9000 head

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