technobeam color wheel problem

[quote=sosumi;44102]I have a technobeam tha
t just yesterday the color wheel stopped working. It jerks a little like it's trying to move but won't spin. There is a fair amount of resistance when trying to move it by hand, not sure if that's normal. No unusual output on the lcd. Any ideas?

Also I have another one that blew its main fuse, after I replaced it, the unit works fine except shows spinning letters/symbols on the led 24 hours a day, whether on, in use or idle mode.

Thanks!

If the motor moves freely without power, then that is either a blown driver chip (likely) or a bad phase in the motor (much less likely).

I can't help on the second . . . Techno's aren't on of my "staples" . . .

- Tim

nono, the motor doesn't move without power, with the light on and doing a routine with the other technobeams, everything works fine - gobos, strobe, pan/tilt but it's just stuck on one color, when i open the cover with it on it looks like it's trying to move - i.e. it jerks a little when it's supposed to change but doesn't move on to the next color.

blown motor?

Thanks

[quote=sosumi;44115]nono, the motor doesn't move without power, with the light on and doing a routine with the other technobeams, everything works fine - gobos, strobe, pan/tilt but it's just stuck on one color, when i open the cover with it on it looks like it's trying to move - i.e. it jerks a little when it's supposed to change but doesn't move on to the next color.

blown motor?

Thanks

I meant will it move easily by hand with no power . . . but if it jerks when trying to change, it's most likely a driver chip. Motors coils are passive devices and very rarely fail . . . Semiconductors go out far more often . . .

- Tim

yeah, when I try to turn it by hand with the fixture on it gives me resistance, and it moves in slots/increments - like, I get resistance and then it seems to 'snap' into a position, each position seeming like 1/30th of the wheel or something. I just assumed this is a servo behavior.

What can I do about the blown driver chip?

Thanks

Well, you still haven't really answered the question that I was asking - does the wheel turn freely, when moved by hand, with the fixture turned off? I am assuming yes, based on your comments, but still not quite sure . . . .

To test, you can try a couple of things . . . the driver chips are U18 through U25, and the part type is 3773, which are pretty common, inexpensive, and easily available, and should be socketed. Unfortunately, I can't find a diagram specifically telling you which one drives the color wheel, but usually a good look at the board will make that apparent. Once you have that figured out, you can either swap the chip with say the gobo wheel driver chip, and see if the problem moves, or you can swap the motor leads on the board and see if the problem moves. If it does, you need a new driver chip. If not, it's the motor or a broken wiring harness . . .

All the driver chips are socketed, so swapping parts to test is pretty simple. Hopefully someone else here can give you the specific chip number for the color wheel driver . . .

- Tim

Oh, with fixture powered OFF... sorry, I misunderstood. I will try it when I get home.

Thanks for the help!

All the wires should be labeled to determine the color wheel chip. Swap them around and see if that fixes your issue. If not, probably a motor. I had a similar problem recently and it turned out to be a short in one of the wires going to the motor. Lightparts carries the chips and have been working all holiday season (thank God, they saved my new years eve show).

so i very carefully swapped successive sets of driver chips, right to left, unplugging the fixture between swaps and observing its behavior when back on...

i finally got to the last 3 on the left, after i swapped them and plugged the fixture back in, i smelled a nasty smell and the fixture went to NNNN. i immediately unplugged it, one of the two chips i just swapped smelled burnt (the main pcb smelled fine). i took it back out and from that point forward instead of NNNN the LED display was fully lit up (all segments).


I assume my main PCB is fried? If so, does anyone have any suggestions on how to fix it cheaper than buying a brand new PCB from high end for $500?


Thanks... :( :( :(

There are very, very few cases where a board replacement is truly in order. If all else fails, give LightParts a call - they can usually service pretty much anything for well below the cost of replacement.

Any chance that you errantly swapped a chip that wasn't a driver, or got one in backwards? Just swapping stepper drivers should not be able to cause a problem like this . . . .

- Tim

[quote=tadawson;44313]There are very, very few cases where a board replacement is truly in order. If all else fails, give LightParts a call - they can usually service pretty much anything for well below the cost of replacement.

Any chance that you errantly swapped a chip that wasn't a driver, or got one in backwards? Just swapping stepper drivers should not be able to cause a problem like this . . . .

- Tim

it was a total pain in the ass, i switched them one by one right to left (with the fixture in the air mind you!)

the only thing i can imagine is either A) one of the leftmost chips arent drivers, b) i got the chip in 1 pin off, or c) a pin got bent and didnt make contact properly.

you think they can fix the board? i will call them tomorrow

Thanks

Didn't you check the part numbers on the chips when you swapped them to be sure?

Oh well, what's done is done . . . . in any case, yes, I would be very surprised if the board was not repairable . . . . short of being broken in half or burned to a cinder, just about any PCB is serviceable . . .

- Tim

yeah the chips all looked exactly the same.

:(

thanks again for all the detailed help.

Dmitriy

I fine more offten that in (techs anyway) it's the motors. now as far as what happen to the chips, you might have been off a pin or flip one or both the wrong way and that WILL blow them as so as you turn it on.