Wells Gardner - Scan Lines or Interference??

Savage Entertainer

Quiz Detective
Joined
Apr 4, 2001
Posts
85
Hi Guys,

I've just finished restoring my MVS-4 ver 3, and have been playing Blazing Star, Rage of the Dragons and Mark of the Wolves. As with most things, the longer you play, the more discerning you become, and the more issues you pick up on - some call it obsession (at least the good lady does :p )

To cut to the chase, I had an issue with lines on the monitor, these started off as discernible pin-stripes, and on the advice of tooddddyy (thanks mate), turned down the lower pot on the fly-back transformer - problem solved.

However, I have now picked up an issue with what look like diaganol waves washing across the screen from the lower-right to the upper-left. I've maximised the brightness pot on the remote front control, and reduced the lower-pot on the fly-back transformer until the picture is sufficiently bright as to be acceptable - lowering screen voltage seems to have had a positive, but limited impact on matters.

The swathes of diaganol lines seem to appear at short intervals - blink your eye and all's well, blink again and there are the lines - a pulsing effect in slow motion.

Black is the least affected colour, white the most affected. Mileage varies on mid-palette colours.

The monitor set-up grid is perfect - pin sharp and waver-free.

From looking at the pics below, could anyone advise me as to whether the symptoms look to be due to:

1. Interference
2. Leaking caps
4. Poor earthing
5. Scan lines
6. The dated technology (all WG monitors do this)
7. Something else

...and advise as to the best way to overcome the issue, assuming that there is one.

Any help would be really appreciated.

Many thanks,

SA

Best example - diagonal waves clearly visible on the wrist of the Lone Wolf!
P8280232.jpg


Mystery - no issues with the chops of Lynn Baker :conf:
P8280226.jpg
 
Last edited:

Gunbu

,
Joined
Sep 29, 2000
Posts
69
<quote>The monitor set-up grid is perfect - pin sharp and waver-free.</quote>

This could be a very important clue. I would clean the video inputs from the pcb to the monitor chassis.
If doing so does not help, it must be the monitor itself, which is a whole 'nother ball of wax.
Worst case scenario, you need a cap kit.
 

Savage Entertainer

Quiz Detective
Joined
Apr 4, 2001
Posts
85
Gunbu said:
<quote>The monitor set-up grid is perfect - pin sharp and waver-free.</quote>

This could be a very important clue. I would clean the video inputs from the pcb to the monitor chassis.
If doing so does not help, it must be the monitor itself, which is a whole 'nother ball of wax.
Worst case scenario, you need a cap kit.

Thanks Gunbu, I've cleaned the JAMMA fingerboard on the 4-slot, which was lightly tarnished, but unfortunately the problem remains.

I may have to go down the cap kit route, but as the issue is relatively minor (no folding), I'm loathe to bite the bullet without first eliminating the probability of interference.

Thanks again,

SA
 

not sonic

King of Typists,
15 Year Member
Joined
Dec 12, 2003
Posts
9,327
try wrapping the video wires around a round ferrite magnet, the ones with the holes in em.

so stick the wires through the hole, and wrap around and come through the hole again
 

ttooddddyy

PNG FTW,
Joined
Nov 29, 2001
Posts
8,335
Run another seperate ground connection between the mobo ground and monitor ground.
That should fix it.
 

Savage Entertainer

Quiz Detective
Joined
Apr 4, 2001
Posts
85
ttooddddyy said:
Run another seperate ground connection between the mobo ground and monitor ground.
That should fix it.

Thanks ttooddddyy, I need some clarification though. I've made a lead with crimped hoop connectors, and attached one end to the corner of the mobo cover, and the other end to the chassis.

Thing is, this hasn't made any difference - to get a good ground, should I scrape the powder coating away from the mobo cover, and clean the tarnish on the chassis (may be this is why it hasn't worked)? Also, instead of crimping the connectors on to the lead, would I be better to solder the joint?

Thanks again,

SA
 

Savage Entertainer

Quiz Detective
Joined
Apr 4, 2001
Posts
85
not sonic said:
try wrapping the video wires around a round ferrite magnet, the ones with the holes in em.

so stick the wires through the hole, and wrap around and come through the hole again

Thanks not sonic, I'll look in to this one. I'll check with Maplins to see whether they have ferrite rings available, and give them a go. Good stuff!!

Thanks again.

SA
 

ttooddddyy

PNG FTW,
Joined
Nov 29, 2001
Posts
8,335
Savage Entertainer said:
Thanks ttooddddyy, I need some clarification though. I've made a lead with crimped hoop connectors, and attached one end to the corner of the mobo cover, and the other end to the chassis.

Thing is, this hasn't made any difference - to get a good ground, should I scrape the powder coating away from the mobo cover, and clean the tarnish on the chassis (may be this is why it hasn't worked)? Also, instead of crimping the connectors on to the lead, would I be better to solder the joint?

Thanks again,

SA

To be sure you have a good connection solder a wire to the mobo ground and same on the monitor ground. This often rectifies that type of prob.
 

Savage Entertainer

Quiz Detective
Joined
Apr 4, 2001
Posts
85
ttooddddyy said:
To be sure you have a good connection solder a wire to the mobo ground and same on the monitor ground. This often rectifies that type of prob.

Fixed :lol:

I must admit, I wasn't sure quite how to take this forward :conf: , but after a quick browse of HardMVS for wiring diagrams, and a couple of hours of free time and some initiative, we're in business.

Thanks for the input guys.

SA
 
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