Lite Puter DX-401 dimmer packs

[Stuart91]

I've had a good handful of Lite PuterDX-401 dimmers in hire stock. They have, in general, been great and a very worthwhile alternative to Multidim-esque efforts for small rigs. However, over the last wee while a number seem to have had their DMX inputs fail. (The channels still operate when the test button is pressed, but the DMX input is entirely unresponsive)

 

So far I've opened a few up for a nosey around inside. Alas there's no obvious simple fault like a ribbon cable fallen off. I'm guessing some part of the input circuitry has failed, but it's hard to guess what exactly. I was hoping to just order up some spare DMX boards and swap them over, but the parts don't appear to be available. I was wondering if anyone has tackled this problem and found a solution?

[dbuckley]

If all the buttons and LCDs operate as intended then the microprocessor is running just fine, so the fault is almost certainly in the DMX receiver chip, probably a SN74156B or equivalent, an 8 legged beastie.

[timsabre]

probably a SN74156B or equivalent, an 8 legged beastie.

 

75176 is the number...

 

like this if it's a dip version, but it comes surface mount as well

http://uk.farnell.com/1103022

[Stuart91]

Thanks - that sounds promising.

 

And at that price, I think I can afford to try some out. :)

[Don Allen]

If it is the 8 pin dual in line plastic package as shown in the link above, the last letter of the part number P is the package style, to minimise damage to your circuit board, cut the legs of the suspect ic off with a small pair of cutters, unsolder each leg individually, then solder in a 8 pin DIP socket in case you have another faulty 75176. This style of socket is raised above the circuit board and there is enough clearance for a small cable tie to secure the 75176 in if you are worried about it coming out over time.