RE: LV2000 demands

On Fri, 13 Nov 1998, Clay Cowgill wrote:

> For what it's worth, when I was doing the Sega Multigame, I had the
> low-voltage section on a WG deflection board spontaneously smoke. The
> board had been running fine after a Zanen Get-well kit for about a
> month. Nothing tricky was going on deflection wise, and none of the
> deflection transistors were bad-- the LV just roasted. Looked like a
> Zener or transistor went. Installing the LV2000 without any other mods
> or repairs fixed it.

        What's in the Zanen kit? I've never used one of those either...

        Does it upgrade the MPS-A56 to an NTE50-like package, like
is in Gregg's FAQ?

        What does the kit replace the Zeners with?

        When I've rebuilt LV sections, I've replaced the Zeners with
1N4750s (1W, 27V Zener) and Q101 with an NTE/ECG50. I replace
the smoked resistors with whatever wattage they originally were, and
leave the other diodes as 1N914s as well...

        Q100 failures are rare in my experience, so I just leave them
as MPS-A06s

        Zanen has used sub-speced parts before -- I wonder if that is
the common denominator?

        It's also my opinion that you're better off without a Zanen
kit when fixing these monitors. I've never had a cap-related problem
on the deflection board. On the HV board -- yeah, but never on the
def. board. When I found out the Zanen Amplifone kit had sub-speced
parts, and the G08 kit had sub-speced parts, I decided to shy away
from them for vector monitor repair. Their Raster monitor kits are
still great, however!

        I think my exeperiences are very atypical, though. I have
had a ton of deflection amp (on the def. board) failures, while
everybody else seems to think these are rare. My hat is off to
Scott Swazey for posting info on troubleshooting deflection amps
earlier this week. I just need to find a bench power supply (i.e.
better than the switcher that I've been using) now!

Joe
Received on Fri Nov 13 16:57:37 1998