Re: WG6100 deflection board madness

If you have a 'scope, you can test the outputs more safely by running the
monitor with the YOKE unplugged. This will present a no-load situation to
the output transistors and this will be a very low current even if there is
a problem. Thus no more fried transistors during testing. When you get good
deflection on the scope, then plug the yoke back in. DO NOT UNPLUG THE
OUTPUT TRANSISTORS EVER FOR A TEST!!! This will instantly destroy the
drivers...

If you are nervous about a no-load on the yoke, try a couple of 25 watt
light bulbs for the yoke. If one output is bad then the light will lite up,
but this time the load current will be under 1/4 amp, well within the
capacity of the output transistors...It might actually be an interesting
test fixture, now that I think about it, using two 25 watt lights. Someone
out there wanna try it before I get a chance to and report back. I am
curious what a running game would do with these lights in place of the
yoke...how bright, the flicker etc.hmmm if one used small laser/mirror
combos such as are used in the laser light shows one could PROJECT the
vector game on a wall...how about a six foot screen????Wow! This could be fun!

John :-#)#

At 08:53 PM 11/25/1999 -0500, you wrote:
>On Thu, 25 Nov 1999, Doug Jefferys wrote:
> >
> > As long as we're on the subject, I also have a deflection board
> > that eats deflection transistors. When last powered up a couple
> > of years ago, the symptoms were that it displayed a picture for
> > a few seconds and then promptly cut out half the X-side of the
> > screen and blew some deflection transistors. I gave up fixing this one
> > when I swapped it out for my Y-amplification-buggered board. Sigh...
>
>One update - the second deflection board had an open D702, which someone
>had replaced with a 1N4004. I swapped in a 1N4002, which is still beefier
>than the 1N4001 that came with it. The "eats transistors" board now
>appears not to eat transistors, but I haven't left it on that long. It
>powers up with vector clatter but the spot killer remains on.
>
>FWIW, the "bad Y-amp" board is a stock P314, and the "eats transistors"
>board is a P314 modified with the "protection board on stilts" hack.
>
>Later,
>Doug.
>
>--
> dougj |
> @ |
>hwcn.org |

  John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9
  Call (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games)
  http://www.flippers.com
         "Old pinballers never die, they just flip out."
Received on Thu Nov 25 22:12:14 1999