I have taken apart an Hella gen 3 HID ballast and put it back together, and it still works! 
One of my ballasts came with electrical tape wrapped on the high tension wire. Once I undid it I saw this:
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Which motivated me to disassemble the thing to see if there is a way to shorten the high voltage wire and remove any exposed sections. There could be 25000 volts going through this man!
After taking off the cover with T8 bit
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There are three T10 screws inside. Two are at bottom in pic and have been removed, the remaining one is all filled with (lead free) solder. Because it is all filled smooth it takes some investigation to find out. I have to suck out as much solder with pump and wick, then melt in some Chipquik so it stay liquid, all while jamming a T10 bit down the middle and turning the screw at the same time.
This one is "hella" well put together.
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That PLCC chip on yet another circuit board is the main controller. Pry up on the heatsink in the middle on controller side. A tab clips it in place. Takes some major prying to get it loose.
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This frame is right underneath the heatsink, presumably to prop up the sink. The sink has four fingers to keep pressure on the transistors and keep it tight on the frame, which is the real heatsink. The white thing must be the igniter.
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Both out
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The four main transistors are held in place by yet another plastic frame and is all deadlocked with each other :headbang:
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Middle ones are IRF540.
Guess how I get at this?
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Look at the first pic again. See that there's a few desoldered joint. Two joints of power in, 4 joints of igniter, and 3 each of the four transistors and diode all have to be desoldered before the board would come out. My iron was not able to desolder the latter, so I bent the transistors to make some room, then bent that damn frame out of the way. Once it is out, any tears are repaired with solvent glue and it is not put back in on reassembly.
I did not take a picture of the igniter on its own, but it is very well potted, which ruled out any chance of shortening the HV wire cleanly to rid myself of any exposed sections.
So I just put it back together, slip a piece of split loom as extra protection, and wrap it back up.
If you managed to desolder the four transistors cleanly, I believe the circuit board would fall out first, followed by the four, then that bracket. Reassembly would be bracket, heatsink, four transistors, igniter, circuit board, then all joints soldered.
One of my ballasts came with electrical tape wrapped on the high tension wire. Once I undid it I saw this:
Which motivated me to disassemble the thing to see if there is a way to shorten the high voltage wire and remove any exposed sections. There could be 25000 volts going through this man!
After taking off the cover with T8 bit
There are three T10 screws inside. Two are at bottom in pic and have been removed, the remaining one is all filled with (lead free) solder. Because it is all filled smooth it takes some investigation to find out. I have to suck out as much solder with pump and wick, then melt in some Chipquik so it stay liquid, all while jamming a T10 bit down the middle and turning the screw at the same time.
This one is "hella"
well put together.
That PLCC chip on yet another circuit board is the main controller. Pry up on the heatsink in the middle on controller side. A tab clips it in place. Takes some major prying to get it loose.
This frame is right underneath the heatsink, presumably to prop up the sink. The sink has four fingers to keep pressure on the transistors and keep it tight on the frame, which is the real heatsink. The white thing must be the igniter.
Both out
The four main transistors are held in place by yet another plastic frame and is all deadlocked with each other :headbang:
Middle ones are IRF540.
Guess how I get at this?
Look at the first pic again. See that there's a few desoldered joint. Two joints of power in, 4 joints of igniter, and 3 each of the four transistors and diode all have to be desoldered before the board would come out. My iron was not able to desolder the latter, so I bent the transistors to make some room, then bent that damn frame out of the way. Once it is out, any tears are repaired with solvent glue and it is not put back in on reassembly.
I did not take a picture of the igniter on its own, but it is very well potted, which ruled out any chance of shortening the HV wire cleanly to rid myself of any exposed sections.
So I just put it back together, slip a piece of split loom as extra protection, and wrap it back up.
If you managed to desolder the four transistors cleanly, I believe the circuit board would fall out first, followed by the four, then that bracket. Reassembly would be bracket, heatsink, four transistors, igniter, circuit board, then all joints soldered.
