Mac 2K Motherboard Issue

[jandrews]

I know, throw them away! But I've gotta try before the venue will buy new fixtures.

I've got about 30 of these and a few have issues. The most recent one that has stumped me is one of the units won't strike the lamp. I tested a bunch of things and decided to swap the motherboard with a known working unit (trying to clear a magenta error too - turned out being the driver on the board) and when I put in the working motherboard in the unit, it striked the lamp. Could it be something on the motherboard that's not letting the lamp strike?

Thanks!

 

[JD]

Yes. The microprocessor controls lamp on/off.

 

[jandrews]

Do you know if that’s easily replaceable?

 

[FMEng]

It isn't likely to be the microprocessor, but some other component. Is the lamp ballast on the motherboard, or separate?

 

[JD]

Although the motherboard contains the microprocessor, there are other interface parts between it and the lamp ballast. Since there is a DMX command for lamp on / lamp off, the microprocessor does have control of that feature. However, chances are the processor itself may be fine since ALL functions are controlled by it and many others work. Since you are seeing other errors with this board, and changing the board fixes all, it could be as simple as corrupted software in an eeprom. On the other end of things would be a loss of the interface between the processor and the ballast. Without looking at the schematics, the method of control may vary depending if the ballast is electronic or magnetic. Often, the processor will put out a flag voltage that goes through a buffer that then drives a relay or thrysistor that operates the ballast. All these parts may be found on the motherboard.