tech Dim colours

[smartbloke@fastmail.fm]

[ukvac] tech Dim colours
o.k. I've had this problem before but I never did get around to finding
out the answer.

I made up a jamma adaptor to plug into my Universal cab.
Problem is that all the colours are really dim - in fact you can only
really see the red.
I know a bit more about the cab now than when I first had this problem,
and I have traced the video ground line ( connection (d) on the universal
loom, and this is connected to pin 14 on the jamma adaptor, so I know I
have a good connection between the edge connector and the video ground
from the cab - although if I disconnect the video ground from the edge
connector the picture does not change at all.
This is not down to the board - I've got another jamma board somewhere
which does the same thing.

If you want to see what I get on the screen have a look here ;-

http://www.fourfront.ltd.uk/downloads/temp2/tetris.jpg

This is driving me nuts - anyone know where I'm going wrong ?

ta
smartbloke
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[yorkshire_spam]

[ukvac] Re: tech Dim colours
Have you tested the monitor on something else and seen it "working
properly"?

Does adjusting the monitor contrast/colour balance/brightness make
any difference?

Is there some evidence which leads you to think it's a connection
problem?



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[Macro]

RE: [ukvac] tech Dim colours
not all jamma boards seem to actually connect the video ground pin to
anything, and I have seen several cabs that connect the video ground direct
to the ground connection on the cab side, so I assume it's a common problem.

if it doesn;t change when you disconnect it then I would expect that you
have found the problem. try ...

a) connect it to ground on the cab side or a better ground on the jamma
connector (pin 1 or 2 on the jamma (from memory - check this first!!))
b) if that makes no difference, check the wire for continuity

 

[smartbloke@fastmail.fm]

Re: [ukvac] Re: tech Dim colours
The monitor is perfect for any Universal boards I put in the cab ...

On Tue, 11 Mar 2003 07:53:07 -0000, "yorkshire_spam"
<mr.spam@oaksroyd.co.uk> said:
> Have you tested the monitor on something else and seen it "working
> properly"?
>
> Does adjusting the monitor contrast/colour balance/brightness make
> any difference?
>
> Is there some evidence which leads you to think it's a connection
> problem?
>
>
>
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
>
--
smartbloke@fastmail.fm

--
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[guddler]

RE: [ukvac] Re: tech Dim colours
Because Universal boards probably connect video ground to power ground whereas
the jamma boards probably don't!

You're answering your own problem :O)

I never worry about whether a ground is connected or not, if the monitor is dark
/ has sparklies and crap on the picture connect pin 14 on the jamma loom to pin
1 or 2 or 27 or 28. FULL STOP.

Martin.

>

 

[smartbloke@fastmail.fm]

RE: [ukvac] Re: tech Dim colours
Have now connected pin 14 to pin 1.
Pins 1, 2, 14, 27, 28, A, B, e and f are all common.
Picture is still the same...

On Tue, 11 Mar 2003 10:11:33 -0000, "Martin White" <martin@guddler.com>
said:
> Because Universal boards probably connect video ground to power ground
> whereas
> the jamma boards probably don't!
>
> You're answering your own problem :O)
>
> I never worry about whether a ground is connected or not, if the monitor
> is dark
> / has sparklies and crap on the picture connect pin 14 on the jamma loom
> to pin
> 1 or 2 or 27 or 28. FULL STOP.
>
> Martin.
>
> >

 

[smartbloke@fastmail.fm]

RE: [ukvac] Re: tech Dim colours
Ignore that last post - just tried the new adaptor with another jamma
board and it works fine.
Am now thinking the tetris board is knacked.

Does anyone have a jamma cab close by to me (Southampton) whos prepared
to let me pop round some time over the next couple of days and plug this
tetris board in to see if it's shafted ?

ta
smartbloke

On Tue, 11 Mar 2003 10:11:33 -0000, "Martin White" <martin@guddler.com>
said:
> Because Universal boards probably connect video ground to power ground
> whereas
> the jamma boards probably don't!
>
> You're answering your own problem :O)
>
> I never worry about whether a ground is connected or not, if the monitor
> is dark
> / has sparklies and crap on the picture connect pin 14 on the jamma loom
> to pin
> 1 or 2 or 27 or 28. FULL STOP.
>
> Martin.
>
> >

 

[Swallow]

Re: [ukvac] Re: tech Dim colours
In message <20030311195055.1C5F82ADB8@www.fastmail.fm>, SmartBloke
<smartbloke@fastmail.fm> writes

Hi,

If you find your self near Havant, give me a call and I will try it on
my test rig.

Steve.

>Ignore that last post - just tried the new adaptor with another jamma
>board and it works fine.
>Am now thinking the tetris board is knacked.
>
>Does anyone have a jamma cab close by to me (Southampton) whos prepared
>to let me pop round some time over the next couple of days and plug this
>tetris board in to see if it's shafted ?
>
>ta
>smartbloke
>
>
>On Tue, 11 Mar 2003 10:11:33 -0000, "Martin White" <martin@guddler.com>
>said:
>> Because Universal boards probably connect video ground to power ground
>> whereas
>> the jamma boards probably don't!
>>
>> You're answering your own problem :O)
>>
>> I never worry about whether a ground is connected or not, if the monitor
>> is dark
>> / has sparklies and crap on the picture connect pin 14 on the jamma loom
>> to pin
>> 1 or 2 or 27 or 28. FULL STOP.
>>
>> Martin.
>>
>> >