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CDM with intermittent buttons

Posted: Mon Aug 15, 2011 9:41 am
by sataraid1
I have a CDM 1250 with flaky button operation. The up and down buttons are pretty hard to press, and I notice that once in a while when I press the up button, it actually activates the P1 button.

I plan on putting this unit on a remote head, so I'd like to address the button issue when I install the kit.

Should I just get a new keypad as a matter of course? If the black contact points become worn or dirty, will the buttons malfunction? Or can I save the $16 with a contact cleaning? If so, is a microfiber cloth with a bit of alcohol safe?

I have to admit, after working with Maxtracs and GM300s, the control heads on the CDMs seem pretty flimsy. All the contact between the LCD and the control head board is maintained by those tiny tabs? Not impressed.

Thanks as always ...

Re: CDM with intermittent buttons

Posted: Mon Aug 15, 2011 12:37 pm
by jackhackett
I would try cleaning the circuit board first, alcohol should be fine for that, if there's something like coffee or soda on it you can try a damp cloth first, then the alcohol after it's dry. For the buttons I just wipe them lightly with a lint free paper towel. I'm always a bit paranoid about ruining the carbon coating.
Give the board a good inspection to make sure there's no dirt or spills on it.

As for the heads being flimsy, other than people dumping their drinks in them I've seen very little trouble with them, you need to be careful putting them back together or installing the remote kit to make sure the board stays seated, but once it's all together properly you shouldn't have any trouble.

Also... the up down buttons can be a little flaky even on a brand new one, sometimes they'll miss a press, one does it more than the other, I think it's the down button that's worse.

Re: CDM with intermittent buttons

Posted: Wed Aug 17, 2011 7:05 am
by sataraid1
Thanks for the input ...

The head didn't seem to have anything in it other than a fair amount of dust. The speaker was choked with it, but the gasket kept most of it out of the head itself on that side. The board around the mic jack had a significant layer as well. The speaker cleaned out fairly easily with some compressed air, and I cleaned up the board around the mic jack with some Qtips and a dab of alcohol. I washed the keypad itself with hot water and mild detergent. I avoided the button contacts and LCD strip contacts altogether, but at this point I guess I'll give the button contacts a gentle wipe with some alcohol and see what happens.

The LCD wasn't having any issues, so I'm assuming those contacts and the conductive strips are okay. I left the LCD in a sealed bag to keep it from picking up any contaminants while I've worked on the board.

Regarding the construction, it just seems a little odd to have the LCD's electrical connection relying fully on pressure maintained by those tiny plastic tabs, especially since the board itself is repeatedly being pushed back by use of the buttons. I concede that it must do just fine, otherwise there'd be a million comments about people punching the board loose in the control head ... but I can't help but think that for want of two screws, that assembly would be a lot more durable.

Again, thanks for the advice.

Scott