Re: More fun with Star Trek

The grounding path of the G08 monitor is not visually obvious; in fact, you
have to look hard to find where the monitor electronics are grounding to the
chassis.

The video "common" (gnd) goes into the input protection board, to the
deflection board, and meets up with the center tap (CT) from the isolation
transformer on deflection board, then then goes to pins 5and6 on the HV unit
to provide the HV unit with ground. Then, a *single screw* in the upper
corner of the HV unit board connects circuit ground to the metal case, which
is then screwed to the chassis, thus providing ground to the chassis.

The deflection board has a ground wire running the neck board (same pin that
is connected to the DAG).

Other than the ground at the power supply, broken solder joints at the input
protection board, the deflection board where the input protection board
plugs in, and the 10 pin connector on the HV unit all provide single points
of failure, and broken solder joints are extremely common for this monitor.
John's recommendations are basically providing a level of redundancy in the
event that one of the existing paths fails. Other than CT and Video GND, I
haven't seen the Sega XY games do any other grounding to the monitor than
that. Maybe there was a reason for not adding additional grounding?

---- Original Message -----
From: "Christopher X. Candreva" <chris@westnet.com>
To: <vectorlist@synthcom.com>
Sent: Tuesday, April 15, 2003 11:04 AM
Subject: Re: VECTOR: More fun with Star Trek

> On Mon, 14 Apr 2003, John Robertson wrote:
>
> > I am now adding a jumper wire from the monitor mother board that will go
to
> > the monitor chassis, and then ground the chassis to the power supply
with a
> > heavy wire, and run a separate wire from the same point to the logic
board
> > ground plane (solder to the board if the logic boards are not connected
to
> > the cage).
>
> When I added a gound wire from my monitor chassis to the card cage
chassis,
> I started getting incredible distorion on my monitor. Are there specific
> points that it is good to pick up the ground ?
>
> I had to build a complete new power cable from the power supply to the
card
> cage, so I have brand new connectors on both sides. Is this sufficent for
a
> 'fresh' ground from the PS to the cards ?
>
> -Chris
>
>
> ==========================================================
> Chris Candreva -- chris@westnet.com -- (914) 967-7816
> WestNet Internet Services of Westchester
> http://www.westnet.com/
> --------------------------------------------------------------------------
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Received on Tue Apr 15 09:18:01 2003