Batboard

Ok X9000 gurus -

I have a UHF X9000 drawer unit with DVP and MDC-1200, and can not get the control head to power up. It makes a "pop" when I toggle the switch but no lights, self check, no nothing. I only have the control head, no MDC head. I looked for missing jumpers or cut traces and could not find anything that looked different.

I have read Mike Blenderman's notes about special firmware for MDC heads, just wondered if there was something unique on this head that keeps it from powering up.

The radio powers up and works fine using the HCN1033 control head from by test bench.

all of my x9000's pop when i turn them on. when you turn it on and you try to tx does the tx light come on? i know i've hit the dim button from time to time and the display goes out.

It pops like a regular head does, but no lights, no PTT, no audio and it will not let me read the radio or head.

So the radio powers up fine with another 1033 head but not the other one? Could just be a head with a bad power supply, bad caps, you name it. Sounds like a bad head period, not necessarily related to the MDC.

I have one that i just took off a VHF that had MDC in the radio, no special firmware that i can tell and it works fine on my other X9000s.

This sounds like a classic electrolytic capacitor C6 malfunction.
http://www.open.org/~blenderm/syntorx9k ... ml#ch_trbl

The approximate location of C6 on a 1033 DIP head is shown on this drawing (next to U5):
http://www.open.org/~blenderm/images/hln4709_t.gif

C6 determines the watchdog timer cycle time out. If C6 goes bad, the head gets stuck in a constant watchdog reset loop, which also resets the radio drawer. When the reset loop is fast enough, there is no time for the display to be turned on before the next reset. The above link has more information. If C6 has leaked, when you replace it be sure to clean up the mess and repair any PC board traces that may have been eaten through.

Yep, Mike's right on that one. I had a head once that when turned on the backlighting would come on for a second then went out and everything was dead.

Replaced C6 and i was back in business. A quick and easy replacment. If needed i can try to find the part number i used to order replacements from Mouser, they should outlast the control head compared to the crummy caps that Motorola used.

Correct me if am wrong but isn't the 1041 a trunking 9000 head, more similar to a spectra head?

The HCN1041 is a DIP head and works on the X9000. I had a VHF go through here with a 1041 on it.