Tim at reach comm Posted November 23, 2012 Posted November 23, 2012 Hey guys this is my first time posting but many topics here have been very helpful when I get stumped! I currently have a Mac 250 I am repairing that will strike, and after about 30 seconds it will shut off, flash hot and then LERR. The light will freeze up at this point. The light sensor is working fine and the head temperature is around 70F/22C. Any light you can shed on this would be very helpful! Thanks!
gyro_gearloose Posted November 25, 2012 Posted November 25, 2012 If you've tried a new lamp, then the only thing that will cause your problem is a faulty light sensor. Either the sensor itself or the wiring loom for it has become damaged so that the CPU thinks the lamp hasn't struck, even if it has. The HOT error message doesn't mean that the fixture itself is too hot, just that your Mac thinks the lamp hasn't struck because it is too hot. The ballast/ignitor in the Mac 250 isn't powerful enough to re-strike a hot lamp, so if the light sensor tells the CPU that the lamp hasn't struck it will assume that it is because the lamp is hot - hence the HOT error message.
Tim at reach comm Posted November 25, 2012 Author Posted November 25, 2012 The light sensor is working though, I get the lamp light on the control panel when the lamp is on. I even have swapped it with a known good sensor to see if It was being intermittent.
gyro_gearloose Posted November 25, 2012 Posted November 25, 2012 In that case have you checked the ballast and ignitor? Maybe the ignitor is on its way out, but only fails once the unit has warmed up? It gets exposed to a lot of heat, especially if the tiny little fan in the head wears out or gets blocked up with fluff.
Tim at reach comm Posted November 25, 2012 Author Posted November 25, 2012 Which is the ballast? I'm pretty sure the igniter is the mint green box in the head, correct?
JayeJsav Posted November 26, 2012 Posted November 26, 2012 The ballast s the white transformer in the base, on the opposite side of the base to the power supply transformer. IIRC it's on the display side of the unit. The ignitor is the mint green component in the head. It's mounted pretty close to the lamp though, so it's entirely possible that it is failing once the lamp temperature starts to rise. The other possibility is that either the lamp base or thermal switch has worn contacts. The thermal switch normally gets this issue sooner though as they are on spade connectors. Of course, the thermal switch might be worn out itself, so when the head tilts, the switch goes open circuit. Just repaired one here that had that exact problem!
Tim at reach comm Posted November 26, 2012 Author Posted November 26, 2012 Thermal switch was checked, and wasn't the issue. I'm swapping the igniter now and if that doesn't fix it I'll try the ballast. Thanks for all the help! It was not the igniter, trying to get the ballast out now. I also tried another lamp and swapped the light sensor cables, none of which worked I just finished swapping ballasts. It didn't help the problem. Any other ideas?
gyro_gearloose Posted November 27, 2012 Posted November 27, 2012 Ok, so if you've tried using working lamps, light sensors, thermal switches, ballasts, and ignitors and you're still having problems then the only other thing you could check is the relay on the motherboard. The relay is responsible for turning the lamp circuit on and off, so if the relay is dying then it might explain why the lamp keeps turning itself off.
Recommended Posts
Archived
This topic is now archived and is closed to further replies.