Re: Lunar Lander help

Hi Marc, Dave

Thanks for the advice. I can certainly replace those 4 chips you mentioned
and give it a try. I'll let you know how I do.

I haven't used freeze spray yet on the board. I have really just started to
dig into the problem over the past couple of days so I haven't tried much of
anything other than scoping the inputs to the dacs. One thing that has
bothered me about freeze spray has been that I didn't know if the spray, or
the frost that it creates is conductive or not. If it's conductive, then I
have to be a lot more careful using it on the ICs. Have any idea?

Regards,
Joel-

----- Original Message -----
From: "Marc Alexander" <marcwolf123@yahoo.com>
To: <vectorlist@synthcom.com>
Cc: <joel.rosenzweig@verizon.net>
Sent: Friday, June 20, 2003 12:19 AM
Subject: Re: VECTOR: Lunar Lander help

>
> Hi Joel,
>
> If you'd like to save yourself some trouble and time, apart
> from visually inspecting that all the parts in the video output section
> are there and intact,
>
> Remove:
> 4016 @ D12
> 4016 @ B12
> TL082 @ C12
> TL082 @ A12
>
> Replace the locations with good quality IC sockets, preferably 'machined'
ones,
> after checking that all the track and pads are clean and intact,
> (you'll need 2 x 14 pin and 2 x 8 pin machined IC sockets)
> and put in new 4016's and TL082's. They are cheap and easy to get, and one
of
> them is most likely the problem.
> It may also be one of the AD561 DAC's but they are much harder and more
> expensive to get, so you may as well do a nice replacement job on the
> easier and more likely problem area first.
>
> If you don't have a desolderer you can use pointy snippers to cut the legs
of the
> IC's carefully one by one at the body, then use an iron and tweezers to
remove each
> leg one at a time, then use good quality desolder-wick on the pads.
>
> Anyway I hope this helps!
>
> Best regards,
>
> Marc
>
> ----- Original Message -----
> From: "Joel Rosenzweig" <joel.rosenzweig@verizon.net>
> To: <vectorlist@synthcom.com>
> Sent: Friday, June 20, 2003 1:26 PM
> Subject: VECTOR: Lunar Lander help
>
>
> > Anyone know what the Lunar Lander self test is supposed to do with
respect
> > to a video display? My LL displays an image and plays in the normal
game
> > mode, but doesn't display anything in the self test. Switches on the
> > control panel do activate sounds during self test though. I assumed
that
> > the self test would behave similar to Asteroids so that I could see a
cross
> > hatch style pattern on screen. Is LL self test supposed to be blind?
> >
> > I wanted to see a cross hatch pattern so that I could more clearly
identify
> > the problem I'm having with the video output. Basically, there's a
vertical
> > column of video, about 2-3 inches wide that spans the entire height of
the
> > display, starting at the left edge of the 4 digit score, fuel counters,
> > extending to the right. Video objects that are in this column get
totally
> > distorted, almost as if stretched fully between the left and right
edges.
> > Then, once the object passes out of this column, it regains its shape,
and
> > looks normal again. The lunar terrain that occupies the space below
turns
> > into a broken line that stretches from side to side. I'll have to take
a
> > picture to give you a better description. It's really odd looking.
> >
> > When I hook up a scope, the problem usually goes away! Hah. I finally
> > caught the problem on the scope, i.e. it's not a monitor defect. I've
> > noticed that the problem comes and goes, and has no relation to being
first
> > powered on, or having the machine sit powered on for a while. The
problem
> > essentially "drifts" in and out slowly. Given the drifting, it has a
real
> > analog feel to it, like a bad cap somewhere, but I haven't gotten to the
> > point where I've located a candidate. I'm not convinced a cap could
even do
> > this. I scoped the inputs to the DAC while having the problem, and the
> > inputs are all toggling. That in itself isn't a proof that the inbound
> > digital data is sane, but at least no inputs are stuck.
> >
> > I'd certainly enjoy hearing any suggestions for what to look at. I'll
try
> > to study the schematics some more, too. And if you think a picture
might
> > help out or at least entertain you, I'll take one tomorrow and post it.
> >
> > Regards,
> > Joel-
> >
>
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Received on Sat Jun 21 09:31:19 2003