Tempest brightness inconsistent

I'm considering buying a Tempest game. It's in pretty good shape, but sometimes
when I was playing it the whole screen would suddenly get a little dimmer. A
minute or two later it would get bright again. The change was rather subtle and
didn't affect playability any. Also, the high-score screen seemed to shimmer a
little like it couldn't keep the brightness consistent. Otherwise, the display
was very sharp and clear. Has anybody seen this before? Is it something that
would likely be fixed by installing one of those Zanen kits or the LV2000
modification? I'm hesitant about messing with it, since otherwise the display
looks great (and I could easily live with it the way it is). Any advice would
be appreciated.
Received on Tue Sep 8 12:54:03 1998