Quite a Poorly Mac 250 Krypton

[Matt_Jabba]

Hello BR, my first post here, hope to find solutions to a problem I have..

 

Yesterday one of my 250 Kryptons lamp went unexpectedly. I replaced the lamp to find it would not strike and instead showed 'HOT' then 'LERR' (light sensor - this is working fine as checked with a torch).

 

Trying to get to the bottom of the problem I took a known working 250 krypton and exchanged the ignitor in the yokes - the good 250 worked, the bad one not.

 

Then checked the ballast and again swapped with the good head. The good head worked as expected. The not-so-good head, no response. Swapped ballasts back as before and good head is fine, the not-so-good now does nothing at all.

 

Power is getting into the bad head, I have checked the incomer fuse and 2 fuses on the motherboard in the arm - all good. Some of the LED's on main board light up, and the usual initial 'clonk' sound before any motors move is kind of made. Display does not light up and nothing moves. I have not left it plugged in for any length of time for risk of any further damage.

 

I am at the stage where I presume I have a wiring set issue with the lamp not striking or relay, but am very unsure why this head now doesn't want to do anything what so ever..

 

I'd appreciate any input anyone may have.

 

Thanks,

 

Matt

[Dj Dunc]

One thing Ive found (as a quick reply, others will be able to help in more detail) is that our Macs went off for maintainance, and one came back still dead, with the same problems as yours is exhibiting (no display, inital clonk but no life). Turns out the display +5v was plugged in the wrong way around when it was removed, hence the head doesnt get any juice into the circuits.

 

HtH

 

Dunc

 

EDIT2ADD: this was the symptoms given by ourselves to our usual repair tech, and that was his solution at the time.