G

Guest

Guest
Archived from groups: rec.games.vectrex (More info?)

Hi all,
I picked up a faulty Vectrex unit this week and I'm just wondering if anyone
would know any common or stock faults with these. I'm quite a competent TV
engineer but a point in the right direction never goes amiss :eek:)
The symptoms I have are basically that the whole picture is compressed down
into the bottom left of the screen but what is displayed is just garbage
broken lines etc.
I know if I was dealing with an everyday TV receiver I'd be looking for a
sync processor fault but with this vector based technology I'm at a loss.
Is there a 'usual culprit' capacitor or such like? I notice when I touch
IC301 (MC1408P8) which I think is the D/A converter that the picture does
increase in size. I've ordered a new MC1408p8 just to eliminate it but can
anyone help?
Thanks in advance,
Steve
Scotland.
 
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Archived from groups: rec.games.vectrex (More info?)

"Steve Cummings" <scsc00705@blueyonder.co.uk> schreef in bericht
news:OzOTd.226045$K7.93576@fe2.news.blueyonder.co.uk...
>
> Hi all,
> I picked up a faulty Vectrex unit this week and I'm just wondering if
> anyone would know any common or stock faults with these. I'm quite a
> competent TV engineer but a point in the right direction never goes amiss
> :eek:)
> The symptoms I have are basically that the whole picture is compressed
> down into the bottom left of the screen but what is displayed is just
> garbage broken lines etc.
> I know if I was dealing with an everyday TV receiver I'd be looking for a
> sync processor fault but with this vector based technology I'm at a loss.
> Is there a 'usual culprit' capacitor or such like? I notice when I touch
> IC301 (MC1408P8) which I think is the D/A converter that the picture does
> increase in size. I've ordered a new MC1408p8 just to eliminate it but can
> anyone help?
> Thanks in advance,
> Steve
> Scotland.

I don't know that much about Vectrex repair, but that chip was the one I was
thinking of before I read you already noticed it. It's indeed the D/A
converter for the vector graphics.
The Philips version of that chip also works in the Vectrex, that's what I'm
using.
 
G

Guest

Guest
Archived from groups: rec.games.vectrex (More info?)

Thanks, that helps me feel a little more confident. Have you had to change
one in your Vectrex before?
I'll let you know how I get on once the IC arrives.



> I don't know that much about Vectrex repair, but that chip was the one I
> was thinking of before I read you already noticed it. It's indeed the D/A
> converter for the vector graphics.
> The Philips version of that chip also works in the Vectrex, that's what
> I'm using.
>
>
 
G

Guest

Guest
Archived from groups: rec.games.vectrex (More info?)

I might be completely wrong as I'm just learning monitor repair now
(going on an arcade school 5 day course in September, so will be a pro
at the end of the year lol)

but I 'think' each quarter of the screen is controlled on vector
monitors in channels, the X channel represenets parts of objects from
LEFT to RIGHT and the Y TOP to BOTTOM, you must have both X and Y
inputs to get a complete picture. The voltages should be equal. Your
quarters are -X +Y / +X +Y / -X -Y / +X -Y

Anyway, I'll dip out of diagnosing now, but you should find this
document useful:
http://www.ionpool.net/arcade/tech/bw_vector_monitor_faq.pdf

Michelle


Steve Cummings wrote:
> Thanks, that helps me feel a little more confident. Have you had to
change
> one in your Vectrex before?
> I'll let you know how I get on once the IC arrives.
>
>
>
> > I don't know that much about Vectrex repair, but that chip was the
one I
> > was thinking of before I read you already noticed it. It's indeed
the D/A
> > converter for the vector graphics.
> > The Philips version of that chip also works in the Vectrex, that's
what
> > I'm using.
> >
> >
 
G

Guest

Guest
Archived from groups: rec.games.vectrex (More info?)

"Steve Cummings" <scsc00705@blueyonder.co.uk> schreef in bericht
news:5A_Td.190275$B8.116511@fe3.news.blueyonder.co.uk...
> Thanks, that helps me feel a little more confident. Have you had to change
> one in your Vectrex before?
> I'll let you know how I get on once the IC arrives.

No, I didn't have to, I was just interested if the Philips chip would work,
the one that was in there wasn't defective or anything, so I exchanged them
and it worked perfectly.
It was in a socket, so it was really simple to do ( using a small
screwdriver, alternating between lifting each end of the chip).
 
G

Guest

Guest
Archived from groups: rec.games.vectrex (More info?)

Thanks Michelle, some interesting reading!
Will let you know how I get on. Good luck with the Arcade School!
Steve



"Shellski" <mkstanton@btinternet.com> wrote in message
news:1109505763.156383.134610@z14g2000cwz.googlegroups.com...
>I might be completely wrong as I'm just learning monitor repair now
> (going on an arcade school 5 day course in September, so will be a pro
> at the end of the year lol)
>
> but I 'think' each quarter of the screen is controlled on vector
> monitors in channels, the X channel represenets parts of objects from
> LEFT to RIGHT and the Y TOP to BOTTOM, you must have both X and Y
> inputs to get a complete picture. The voltages should be equal. Your
> quarters are -X +Y / +X +Y / -X -Y / +X -Y
>
> Anyway, I'll dip out of diagnosing now, but you should find this
> document useful:
> http://www.ionpool.net/arcade/tech/bw_vector_monitor_faq.pdf
>
> Michelle
>
>
> Steve Cummings wrote:
>> Thanks, that helps me feel a little more confident. Have you had to
> change
>> one in your Vectrex before?
>> I'll let you know how I get on once the IC arrives.
>>
>>
>>
>> > I don't know that much about Vectrex repair, but that chip was the
> one I
>> > was thinking of before I read you already noticed it. It's indeed
> the D/A
>> > converter for the vector graphics.
>> > The Philips version of that chip also works in the Vectrex, that's
> what
>> > I'm using.
>> >
>> >
>
 
G

Guest

Guest
Archived from groups: rec.games.vectrex (More info?)

Have you found the Vectrex Service Manual and the Troubleshooting
Guide?

Look for the downloads at www.playvectrex.com

Rob Mitchell, Atlanta, GA
 
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