Author Topic: Is this Grandstand FIREFOX F7 VFD game repairable or only good for spares?  (Read 571 times)

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Offline Max PleasuresTopic starter

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This Grandstand Firefox F7 was badly corroded to the logic board. I have extensively cleaned it and reflown every solder joint. Alas, the two columns right of the centre one do not display properly. They are very faint and as can be seen, some detail is missing. Is this a CHIP issue? Is it repairable or is it finished? I know that you can pass extensive current but I'm not sure this is a phosphor issue? Any advice before I scrap it would be hugely appreciated. Many thanks in advance
 

Offline Max PleasuresTopic starter

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Anyone any suggestions for this please?
 

Offline coromonadalix

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pls do not pressurize people to answer, some may or will or if they want ... and you may not get answers ...
 

Offline cruff

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You can probably start with determining if you managed to clean all the corrosion that might be under chips and other larger components, which might involve removing them. Then look for traces or leads that have lost enough metal to become more resistive than they should be. Do you have a magnifier available to examine the board closely?
 

Offline Gyro

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I doubt it is a phosphor issue (presumably each symbol will have be illuminated for roughly the same length of time) or filament emission (that would be more likely to follow the lines of the horizontal filaments). It looks more like the vertical grid drivers to me, try tracing back the grid connections and compare the signal levels with those of the working columns.
Best Regards, Chris
 
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Offline Max PleasuresTopic starter

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Thank you for your advice.
 

Offline Max PleasuresTopic starter

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I wasn't pressurising anyone to respond. I was seeking a diplomatic and tactful means of bumping the post as it had disappeared from the page.
 

Offline Max PleasuresTopic starter

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Thank you, yes, I have a microscope There is a LOT of decay to some part of the board. I may well have to strip it down and try and study further. Thank you for the input.
 

Offline Max PleasuresTopic starter

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I doubt it is a phosphor issue (presumably each symbol will have be illuminated for roughly the same length of time) or filament emission (that would be more likely to follow the lines of the horizontal filaments). It looks more like the vertical grid drivers to me, try tracing back the grid connections and compare the signal levels with those of the working columns.

Again, thank you. I shall try this. It just appears to be those two columns to the right of the centre column. Most annoying!
 


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