Big Buck Hunter Pro Gun Issue (Makvision Display)

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Hi,

I don't know if this should be posted in this section or the repairs section but I am hoping that someone with the information please comes forward as this problem is driving me crazy!

This is an ongoing issue over the years and I have searched the forums and the internet countless times and cannot come up with a definitive answer to this problem.

I have had several Big Buck Hunters over the years, Pro, Safari and World and the problem effects all versions of the game.

The problem is the gun calibration specifically the Gun Tracking or The Signal Strength which depending on the display dies out to zero before reaching the edge of the display.

On some displays the sight works great all the way to the left, right and up but try to shoot something at the bottom 20% of the display and the gun does not register.

On other displays the sighting works great up and down but try to shoot something at the left or right edges and nothing.....

I have tried resolving this by swapping computers, I/O PCB's, new optics in the shotguns, rebuilding the chassis and even rejuvenation of the CRT even though the emissions were in the green and nothing helps.

The information I have come across is basically the same, "those Makvision displays are crap" but that does not explain why this is especially as when I put a test pattern on the display it is vibrant and detailed.

From what I understand the guns "look" for the scan lines and that determines where the gun fires at a given point in time. Using this I would have to assume that somehow the display is not producing the required scan line strength -- but to the naked eye, the display is working correctly and looks good.

Just for demonstration purposes I uploaded a video of the situation I am trying to resolve. This is a game with a rebuilt chassis, rejuvenated CRT, rebuilt computer and new optics in the shotguns:


This display is worse than the one I just swapped as the guns fail sooner that the previous one that shot great top, left and right but bottom no good.

This issue changes (better or worse) when I swap displays so the issue is with the displays and not the cabinet (components).

Does anyone know what component(s) on the display cause this very very frustrating situation and / or has anyone resolved this in some way???

I would really really appreciate a solution to this decade old problem which I have yet to solve.

Thank you in advance and thanks for listening.....

Jeff
 
Checking the schems I see that there is a 12MHz crystal (XT1) on IC2 pin 7 and 8, could this have something to do with the timing of the scan lines and therefor the sighting system?
 
OK, had enough so went to the treasury and pulled out one of my prized NOS (still in the original box) Wells Gardner 27D9200 Tri-Mode displays, hey I'm not going to live forever.......

Although it is not a "flat-face" like the Makvision it fits surprisingly well.

Fabricated a power connector adapter and hooked everything up. Applied power and witnessed one of the finest BBH displays my eyes have ever seen - spectacular.....

So now for the test, calibrated the guns and went into the Gun Tracking / Signal Strength and received "green" (great) to all edges of the shooting areas on both shotguns.

This proves once and for all that it is in fact the display and not the other components in the game causing this situation.

So back to the original question, why even after the rebuilding of the chassis (ALL electrolytic caps replaced) and the rejuvenation of the CRT RGB guns (even though the readings were originally in "green") there remains this problem. What would prevent the display from producing the required scan line levels that the guns require??

I can not find a replacement HVT for this chassis, could that be the cause in some way???

Before I die, I need to solve this once and for all........
 
....so basically need to check the components that produce the scan lines but due to my lack of required knowledge in this field - I am in need of assistance on this one....
 
BTW, heard back from Peter at AP&R and he is currently working on a replacement HVT for the 2929 - keeping fingers crossed.....
 
Going forward I pulled the NOS WG and subbed a rebuilt 27D9202. The chassis was completely rebuilt including the HVT. Tested the guns with my B&K and all in the upper green.

It shows it age and the display is no where as clear and vibrant as the NOS but for a display as old and used as this it is just fine. In fact the image is exactly the same as the Makvision, good but not great.

Now here's the difference..... although the image is similar, the guns track exactly the same as the NOS display. Edge to edge.... game plays great.

So could the issue be that the old Makvision although rebuilt and guns cleaned still has the original HVT??

Could this be a voltage issue???
 
I have the same problem with my Makvision monitor. The tube is in the green on my tube tester and I've completed a recap along with a flyback replacement. I'm really interested to see the results if you replace the HVT.
 
This is an issue i have come across a dozen times and have never found out why....
There must be a reason/ component that is at fault.....and there's got to be SOMEONE who knows why!
Don't take it to your grave.....give it up!
 
BTW, where did you find the HVT for the Makvision?
Is it a dual or single focus?
I ended up cannibalizing another chassis. For all I know the replacement was defective too. But the set came alive again so I didn't question it at the time.
 
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