DIYbanter - Sanyo LCD projector lamp power supply

I've got an Eiki LC-7000 (aka Sanyo PLC-5500) projector. The lamp power
supply failed at some hundred hours of the second lamp - and guess what
the owner did? He bought a new one (third one for the projector)...
Now I have a projector (which works fine with another light source) and
two lamps. I already have a CRT projector so I thought I'll repair this
and give it to my boyfriend to play with (maybe he'll stop complaining
for a while...)
I replaced 4 shorted transistors (2SC4424). Now the ignition seems to
work fine, and a blue arc lights in the lamp.
However, the lamp never gets the actual operating current. I didn't
expect it to be this easy, and traced further. The 4 transistors are
driven by integrated optocoupler-driver-IC:s (PS9634), and 2 of them
were getting warm and measured some nice zero ohms.

What else should I check? I found only passive components which tested
OK, and except the rest of the supply to be fine because of
optocoupling. I also think it blew because the first lamp of the
projector was used until it exploded causing some damage, so just
replacing the semiconductors should fix it. Ordering these rare Japanese
semiconductors from the US is a bit pricey, so I'd like to get all of
them at once.

Thanks,
Jussi