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K7000 Intermittent vertical collapse

Printed From: ukVac.com
Category: Technical
Forum Name: Tech, Maintenance & Repairs
Forum Description: Need Help? Ask Here
URL: http://www.ukvac.com/forum/forum_posts.asp?TID=376002
Printed Date: 29 Mar 2020 at 12:18am


Topic: K7000 Intermittent vertical collapse
Posted By: K1ngarth3r
Subject: K7000 Intermittent vertical collapse
Date Posted: 25 Mar 2020 at 5:07pm
I have a Well Gardner K7000 monitor that has a few niggling issues:

Monitor has been re-capped and has had a new flyback installed in the last few months since I've owned it (The Flyback was bad when I had it but understood it worked okay for the previous owner up to that point). 

Heres the issues:

1) Intermittent vertical collapse

It can be absolutely fine, and then after I switch it off and move some cables (none specifically appear to cause it) I will have vertical collapse. 

 
2) Video jumps intermittently, I get occasional rolling screen and then other times its solid image for ages. Possibly fixed with 50/60hz pot as the image seems stable. 

3) Degaussing issues, this didn't happen when the monitor was upright but since turning upside down for a light gun game its giving me some issues on the left and right sides of the screen (mostly on the right as you face from the front of the cabinet. 

I think this is because the cable that goes around the monitor is very loose, repositioning this cable (or is it a degaussing harness?) makes a difference, so I guess I need a way to help it stay close to the tube whilst it's upside down...



4) There is a vertical line about 1/4 down the screen, I believe this could be a 50 60 pot adjustment to fix this one though. 

Reference:  https://forums.arcade-museum.com/showthread.php?t=175666" rel="nofollow - https://forums.arcade-museum.com/showthread.php?t=175666

Fixed with 50/60hz pot


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Most wanted PCBs: Ghouls N Ghosts, Splaterhouse, Rainbow Islands & Bubble Bobble



Replies:
Posted By: dieold
Date Posted: 25 Mar 2020 at 10:22pm
I recently had a vertical collapse on my Wells Gardner K7000. I had been doing a bit of refurbishment on my cabinet and had the working monitor in and out a few times for cleaning the cabinet and also to check an old Hantarex monitor I have which was working (just) when I stored it away. When I put the K7000 back in I had vertical collapse. I searched the internet for possible causes and actually replaced the vertical IC but no difference. I checked a couple of diodes which were OK. I seemed to go round and round seeing the same suggestions. One thing I dismissed really was damage to the adjustment pots in particular the vertical ones. When I examined these with a magnifier the vertical hold pot was cracked on one of the plastic legs. I ordered a new one but actually repaired the original one by superglueing the crack together on the edges then bridging the crack with electrically conductive paint and it has been fine ever since. I should have realised that moving the monitor in and out might have caused some physical damage. So in my case it was an easy fix. Worth checking.


Posted By: big10p
Date Posted: 25 Mar 2020 at 10:33pm
If you have a remote board, check it's connected properly.


Posted By: K1ngarth3r
Date Posted: 26 Mar 2020 at 8:24am
Thanks both, I do think it could be the remote board since when I shut the coin door it sometimes triggers it. I will reflow all the connections for the remote board on chassis and remote board itself. 

Also, if anyone knows where I can order new pots from let me know, I'll order them and replace to be sure they will last.


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Most wanted PCBs: Ghouls N Ghosts, Splaterhouse, Rainbow Islands & Bubble Bobble


Posted By: gunblade
Date Posted: 26 Mar 2020 at 8:52am
yes sounds like a fractured vertical size pot or bad solder joint/connection to remote board


Posted By: K1ngarth3r
Date Posted: 26 Mar 2020 at 9:38am
Thanks for all the input, it's reassuring that we're all on the same page so hopeful for a fix.

I read some places did pot kits for the remote board (In the US) but realise the chances of someone doing the same here are slim.

Does anyone know what pots would be a suitable replacement that I can order either from eBay or similar?


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Most wanted PCBs: Ghouls N Ghosts, Splaterhouse, Rainbow Islands & Bubble Bobble


Posted By: big10p
Date Posted: 26 Mar 2020 at 9:42am
If you have a manual - or can find one online - it should have a parts list in it. The resistance will probably we written on the pots somewhere, too.


Posted By: K1ngarth3r
Date Posted: 26 Mar 2020 at 10:16am
Thanks for the prompt, I checked the manual and can see the readings, It's just finding the right size and leg placement that I'm struggling with.



The manual I referenced didn't show the remote board, but can get the pot details from here.


I thought I might as well look at the neck board whilst I'm at it too.


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Most wanted PCBs: Ghouls N Ghosts, Splaterhouse, Rainbow Islands & Bubble Bobble


Posted By: K1ngarth3r
Date Posted: 27 Mar 2020 at 10:46am
I had a quick search for the remote board and think these should be okay for the job.

http://www.ebay.co.uk/itm/5-pcs-Horizontal-Pot-Variable-Cermet-Potentiometer-Trimmer-Resistors-100-to-1M/171513535544?hash=item27ef00dc38:m:mW0l7o4R4ZSLQXkMtSNMSjw" rel="nofollow - https://www.ebay.co.uk/itm/5-pcs-Horizontal-Pot-Variable-Cermet-Potentiometer-Trimmer-Resistors-100-to-1M/171513535544?hash=item27ef00dc38:m:mW0l7o4R4ZSLQXkMtSNMSjw

Heres a picture of what pots are required for the remote board


Links to where to buy each:

25k (Cannot find this one yet)
http://https://www.ebay.co.uk/itm/5-pcs-Horizontal-Pot-Variable-Cermet-Potentiometer-Trimmer-Resistors-100-to-1M/171513535544?var=470538454723" rel="nofollow - 2k
http://https://www.ebay.co.uk/itm/5-pcs-Horizontal-Pot-Variable-Cermet-Potentiometer-Trimmer-Resistors-100-to-1M/171513535544?var=470538454726" rel="nofollow - 10k
http://https://www.ebay.co.uk/itm/5-pcs-Horizontal-Pot-Variable-Cermet-Potentiometer-Trimmer-Resistors-100-to-1M/171513535544?var=470538454721" rel="nofollow - 500 Ohm
http://https://www.ebay.co.uk/itm/Potentiometer-Horizontal-Trim-pot-Trimmer-Variable-Resistor-choice-of-values/263457180747?var=562481649127" rel="nofollow - 500k
http://https://www.ebay.co.uk/itm/5-pcs-Horizontal-Pot-Variable-Cermet-Potentiometer-Trimmer-Resistors-100-to-1M/171513535544?var=470538454720" rel="nofollow - 200 Ohm



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Most wanted PCBs: Ghouls N Ghosts, Splaterhouse, Rainbow Islands & Bubble Bobble



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