Control/Dimming Minstrel Board has no dmx

lwinters630

Well-Known Member
I went to a middle school auditorium today to help with a lighting problem. They have a Minstrel Lite board by EDI connected to a Mark VIII 48 rack. The problem is that when the board is turned on and plugged in all the lights will come on and will not turn off. Unplug the DMX and the lights will shut off in about 30 seconds, which is what I would expect. How ever when the console is connected it will not dim, fade, chase, black out, sub, bump or any thing. All of the indicator leds seem to work fine. Even with all sliders off, most of the fixtures are just stuck on full. (yes they were using the breakers to run a show). I opened it up, all PC boards, no obvious burns or shorts. No fuses. Transformer had voltage in and out.

I brought in another board (omega II, just to match the vintage, HA HA) that I had laying around to test. It had full control and every thing worked fine.

So the question is how to fix the console? Any trouble shooting guides or test procedures?
 
Alan Child should know.

http://ediserviceandrepair.info/

The Minstrel is not mentioned in their list of repaired & serviced equipment, but it's probably a problem he's heard of and could hopefully diagnose over the phone.
 
I have a client with one of these that will only transmit analog. This will control the house lights. The DMX portion of the console is not functioning. The stepdown xformer that supplies the CPU board is putting out just over 9 volts on each side. The rectifier is putting out 25vdc. No components appear to be burnt or fried. Any ideas?
Is there anybody out there that still repairs these?
 
See the link http://ediserviceandrepair.info/ above for repair.
Many times the culprit is the dmx chip. It's probably a SN75176 or similar. Hopefully it's socketed and you can just pop in a replacement to see if that will fix it. Usually in close proximity to the DMX jack.
Available a places like www. mouser.com for about 88 cents each so buy half a dozen.
 
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I do not see an SN75176 chip on the CPU board. Would a UA9638CP Dual High Speed Differential Line Driver be a substitute? It appears to be on the output pins that the XLR plug connects to via wiring.
 
My guess is that it would be a likely suspect. I have some UA9637A in stock from repairing some brand of dimmer and according to the UA9638 spec sheet it is the matching receiver chip. Mouser has 1,215 in stock for 66 cents each!
 
Thanks for taking an interest in helping me out. I'll see if I can get a hold of one and replace it, and then see what happens when I test it out. Certainly cheaper than buying a whole new control console...
 
I'll let you know how it goes. Have to order the part first. None in my area at the local electronics store.
 
If you turn it off and back on again, would that be a Minstrel cycle?
 
Guess you'll have to contact Alan Child at the EDI service and repair site and possibly send the board to him if he's not able to suggest a fix over the phone. Sorry it didn't work out.
 

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