Re: Tempest displays on scope, but not 6100

You did check Z0 Z1 and Z2 right?

Kevin

On Sat, Jun 29, 2013 at 4:06 PM, IAN EURE <ieure@mac.com> wrote:

> I got back to this today, and I'm still completely stumped. I checked the
> RGB outputs, and they seem fine. I compared the X and Y sections
> individually on the scope to a working board, and everything is within
> range. On the RGB outputs, I see them turning off and on like they should —
> nothing stuck there. I also compared those to a working boardset, and they
> seem fine.
>
> I checked the X and Y grounds, and they are fine. It looks like there's an
> error in the schematics, as the video return line is marked as pin M of the
> AVG edge connector, but this hooks to the collector of Q7, which is for the
> middle coin mech. Either way, the ground pins on the 6100 connector have
> continuity to the ground plane on the PCB, and the ground is correctly
> hooked to Q10.
>
> My understanding is that the SK operates by shutting off the beam current,
> no matter what causes it to activate — which is to say, if deflection is
> present, it is unaffected by the spotkiller. This is where I'm hung up: I
> /have/ deflection on the scope, but even when I turn up the brightness on
> the 6100, I have no deflection.
>
> Any other ideas?
>
>
> On Jun 22, 2013, at 8:13 PM, Rodger Boots <rlboots2@gmail.com> wrote:
>
> > If X is good and Y is good make sure ground is also good. A long shot.
> >
> > Well the voltage output on x and y could be out of range for the
> monitor. So I would take the scope out of xy mode and measure the voltage
> output of the x and y. It's probably good from reading your write up.
> >
> > I can't recall if the color output circuit would cause this problem,
> typically I've only seen 1 color go bad before, but maybe you are missing
> all three?
> >
> > I would most likely suspect the z outputs from Data shifter H7 Try
> checking those outputs, and reseat the 2 VG Eproms JIC.
> >
> > Kevin
> >
> >
> >
> > On Sat, Jun 22, 2013 at 6:02 PM, IAN EURE <ieure@mac.com> wrote:
> > I have this Tempest PCB I've been working through. I have it displaying
> a self-test screen indicating some errors that need work, but I can only
> get the screen to come up on a scope. Because I have no Z channel and only
> have 10x probes, I can't read the error codes on the scope. When I hook the
> game to a K6100, I just get a spotkiller.
> >
> > Has anyone seen this before?
> >
> > I know it's not the monitor, because I'm testing in a working cabinet. I
> thought it might be the PCB adjustments, but I used the scope to calibrate
> them to the same levels as another PCB, which does display in this cabinet.
> I turned off & disconnected the scope, in case that was interfering with
> anything; no change. I'm hooking the scope to the X/Y out test loops on the
> board. I thought there might be a broken trace between there and the edge
> connector, but I checked and there is continuity. I turned the screen
> control up on the 6100 to bypass the spotkiller, and all I have is a dot in
> the center; no deflection at all, despite seeing a signal on the scope.
> >
> > What am I missing here?
> >
> > Background: Got the board resetting in game mode and blind in test.
> Cleaned & reseated ROMs, and got it playing blind as well. But it went back
> to resetting a day later, which indicates dodgy ROM sockets. I'd prefer not
> to replace all 10, so I decided to get self-test going so it would tell me
> which were faulty. Replacing the TL082s got me a box in self-test with no
> text, and swapping the ROM @N/P3 got me a reasonable looking test screen.
> But I can only see it on the scope.
> >
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> >
>
>
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Received on Sat Jun 29 17:19:05 2013