Hi wizards, I need a little feedback on an issue I'm having with a Martin MX-4 scanner. I acquired four of these very old discontinued units (Circa 1999) and each one had issues that I have resolved after troubleshooting them one by one. The major issue I've encountered was malfunctioning TILT motors caused by faulty drivers but I resolved this by removing the old ULN2803A drivers and installing new drivers on new IC sockets. If the problem re-occurs, it'll be a simple swap out in the future. One unit however, has me baffled. I've gotten functional PAN, TILT, COLOR and GOBO but the SHUTTER continues to act erratically. So far I've done the following:
1. Replaced all ULN2803A drivers
2. Removed the SHUTTER motor, opened it up and checked but there are no visible problems.
3. Swapped out the SHUTTER motor with the COLOR motor (all the motors carry the came number) and the COLOR functioned fine and the SHUTTER problem continued.
4. Checked all six leads on the SHUTTER motor wire harness for continuity. All fine.
5. Checked all solder traces on the PCB for continuity from the motor terminals to the ULN2803A drivers, then from the drivers to the ATMEL AT90S8515 microprocessor and all the traces are fine.
Having done all this, all that's left for me is to assume that the microprocessor is faulty so I'll have to source a new (secondhand) PCB. Hence I'm throwing this out there for you gurus to take a look at before I commit to trying to replace the PCB.
Any feedback will be greatly appreciated.
Party Animal!!
1. Replaced all ULN2803A drivers
2. Removed the SHUTTER motor, opened it up and checked but there are no visible problems.
3. Swapped out the SHUTTER motor with the COLOR motor (all the motors carry the came number) and the COLOR functioned fine and the SHUTTER problem continued.
4. Checked all six leads on the SHUTTER motor wire harness for continuity. All fine.
5. Checked all solder traces on the PCB for continuity from the motor terminals to the ULN2803A drivers, then from the drivers to the ATMEL AT90S8515 microprocessor and all the traces are fine.
Having done all this, all that's left for me is to assume that the microprocessor is faulty so I'll have to source a new (secondhand) PCB. Hence I'm throwing this out there for you gurus to take a look at before I commit to trying to replace the PCB.
Any feedback will be greatly appreciated.
Party Animal!!