Video tutorials on discharging monitors and “doing” a cap kit

A mere year and a half ago doing a “Cap Kit” stirred a sense of fear of the unknown within me, as well as a feeling of inadequacy that made me feel like a wuse arcade collecting poser too afraid to dive head first into working with electronics.

I searched online for a “how-to”, or a tutorial that would get me a solid definition and visually show me how to perform a “cap kit” . Heck, it took me a week or so just to figure out that cap = capacitor, I was really starting from ground zero, or ground “beisbol” as Warren would say.

Since that time, I have changed a fair amount, not a ton, of capacitors on monitor chassis’s in hopes of fixing minor display glitches in my games. But I still wish I would have had some sort of photo collage or video tutorial showing me how a cap kit was done, and done right.

Last night, I came across these tutorials posted on the BYOAC forums. There are three YouTube videos, two on performing a “cap kit”, and one on discharging a monitor. Two of the well done starter videos were put together by a KLOV member “p1899m”. I wish I would have had these when I started.

The Cap Kit Videos

Before the videos, you might be asking yourself, “How do I know if my monitor needs a cap kit?” Well, here are some symptons that might indicate whether you need to perform this minor electronics maintenance task on your arcade monitor

  • Arcade picture is wavy
  • You have no picture / monitor is dead
  • Your monitor colors are off
  • Lines through the monitor picture
  • Just about any display inconsistency when playing the game

So here are the cap kit tutorial videos. To try to help you out, I have also noted a couple of things that I liked about the videos, or that were left out that I thought might be important to mention. This should not detract from all of the effort that was put into making these. I am sure they took a couple of hours and are yet one more valuable resource for future arcade hobbyists.

Some important notes not covered in the cap kit / discharge monitor videos (Keep in mind, I don’t like to assume anything and figure first time viewers know nothing…);

  • I wouldn’t recommend touching that anode cap with your fingers
  • Don’t know if there is any truth in extra protection to wearing rubber gloves even with an insulated screwdriver, but for those of you who want an illusion of extra protection…
  • Great mention of where to keep hands.
  • Great shots of home made tool for discharging
  • Good that he mentioned discharging more than once is a safe idea

My notes on this cap kit video;

  • Great that he mentions how high the voltages can get – 20,000 Volts +, high enough to kill you
  • How to remove the chassis from the frame once you discharge the monitor?
  • A quick shot or photo of the underside of the anode cup would have been good
  • Great organization of the caps in the foam board
  • Great explanation of the kit from Bob Roberts and the instructions for following the location of caps on board with the numbers on the provided sheet.
  • More detailed shots of the polarity, the stripes, the plus / minus signs, and the lengths of the leads to further clarify an important point.
  • Great explanation of choosing the right “uf” measurement, but as long as voltage is higher the capacitor replacement is ok
  • Might have been good to show how to identify the board model number to purchase a cap kit (Maybe OT, but related)
  • Might mention that there are a couple of ways to remove solder, a solder wick and a solder sucker. Also, make sure to watch yourself with the solder wick, it can get hot.
  • Make a quick mention of cold solder joints and removing all old solder from connections.
  • Great use of materials. Would have been great to show a cut screen of the materials used – rosin, wet sponge, iron, solder wick and solder.
  • In this video, he doesn’t touch on how far away the bottom of the cap should be from the pcb. I had this question for quite some time. Seemed simple to everyone else, but important knowledge for me (highwater caps)
  • Clarify why he doesn’t like to have too much solder on the solder side of the board for connections. Is it just to keep connections from touching?

My notes on this cap kit video;

I don’t have any insightful thoughts for this one, the author basically covers the same ideas on how to perform an arcade cap kit, but is a little less in depth. The tutorial is good because it shows how he holds the board, how he rocks the caps out of the holes and how far to put the caps down to the pcb.

Related Cap Kit References

Of course, always worthy to note when talking about cap kits, The Real Bob Roberts has the best service and good prices / wide selection of already compiled capacitor kits ready to go.

Plus, here is the original link to the cap kit video thread on BYOAC.

What do you think?

Was there anything in these cap kit / monitor discharge videos that was left out that you would like to see, or note to a first time user?

Here are some similar arcade posts

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Hey Jeff,

Regarding the first set of videos…I saw them too on KLOV. Glad someone finally did that. I had a few people on my site asking for a cap kit tutorial. A couple of things I think could be added…

1. This one is not very important to get the job done, but it would be good to mention what “uf” or “µf” actually stands for (micro farad). I think that it’s good to know that, and also good to know that some capacitors (in schematics or parts lists) might be listed as MFD, as in 1000 MFD = 1000uf

2. I think this is more important and don’t remember it being mentioned. Whenever you remove a cap, its important to look at the polarity of the old cap before you remove it. Some chassis have cap polarity markings silkscreened incorrectly on the PCB. Some also might be hard to read or scratched off…I always check the polarity first for that reason and make the new one match regardless of what’s marked on the board.

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Good points on both accounts Jamie.

Number 2, I meant to comment on that one. The second cap kit video, the guy actually mentions that he pays attention to the polarity of the cap before he removes it because he doesn’t trust the board. That is along the same lines I guess, but basically the idea is, don’t just assume anything when it comes to polarity, check the board, check a schematic, and check the polarity of the cap as it is currently mounted.

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Definitely, I encountered the “bad” marking on the board a few times. Gotta check before you pull.

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See…it’s little intricacies about electronic repair like this that I wanted to know about. When I was searching out cap kit tutorials on the internet, the two or three I read didn’t mention anything about checking the board for bad polarity markings against the caps. I always just changed capacitors based on their current polarity on the board or if I took the cap out and came back to the soldering later, went by the board polarity for replacement.

I have been lucky in the 4 or so cap kits I have done so far…here’s crossing my fingers.

My original fear when I started was that I would burn down my house if I didn’t solder something right, and of course incinerate the game…..

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One other good tip that I’m not sure is mentioned in those vids is if you are messing with a big capacitor (or even near one) to discharge it. 🙂

On G07’s, if the HOT goes (or maybe the flyback?) the large filter cap will hold a nasty charge. I got hit by it once when carrying a chassis in from the garage. I also scared the crap out of myself and my wife when I discharged one by shorting the leads together with a scredwdriver. It sounded like a firecracker.

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Jamie: I know the POP of which you write! LOL I caught a Big Cap with a screwdriver once.

I am at work and hence barred from YouTube. I will view when I return home. Do they mention waiting? I was always a fan of discharge and set overnight. Time bleeds these failing caps fairly effectively. Those bottle caps, though. They never seem to die.

Jeff (admin): The only Monitor board I know has a bad marking is the Sanyo (Nintendo). It was documented in the Arcadeshop cap kit instructions. I think that is how I knew to be aware.

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Hey Jim,

Nope…they don’t mention anything about discharging big caps or waiting.

I actually didn’t watch that last video before, but just did. I remove my caps like that…they come out very easily that way. But, I thought it was strange that he didn’t remove the old solder before putting a new cap in it’s place.

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Funny, A Sanyo one one of the monitors I did a cap kit on, it was, strangely enough, in my Dig Dug game. I had some problems due to inexperience with the connector…but never any problems after I capped with the display. I didn’t even know to research any specific monitors for problems with chassis markings.

The author does mention to wait, in increments of 5-10 minutes, discharging the monitor multiple times, like 3-4 times. But doesn’t mention it specifically for big caps. Another thing I didn’t know on my first cap kit, and happy I only worked on really old, not in use monitors that I never had any bad experiences.

I have never found out what “cold” solder means exactly. Is that why you need to remove all the old solder? This is my understanding of cold solder, that you have new solder mixed with old solder and the electricity doesn’t flow through the connection. Is that right?

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Cold solder joints happen when the component leads move before the solder has cooled. Here’s a quote from a website that explains it better:
“A cold joint is a joint in which the solder does not make good contact with the component lead or printed circuit board pad. Cold joints occur when the component lead or solder pad moves before the solder is completely cooled. Cold joints make a really bad electrical connection and can prevent your circuit from working.

Cold joints can be recognized by a characteristic grainy, dull gray colour, and can be easily fixed. This is done by first removing the old solder with a desoldering tool or simply by heating it up and flicking it off with the iron. Once the old solder is off, you can resolder the joint, making sure to keep it still as it cools.”

I haven’t been soldering that long, so maybe it’s OK to do what he did but I always thought it was better to remove all the old solder.

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The first cap kit I ever did was on my Donkey Kong machine. I remember being nervous almost the entire time since all I heard leading up to it was how I was either going to shock myself or how I was going to damage the monitor since it’s so difficult to handle.

In the end I did just fine, but I think the discharge process gave me a glimpse into what it must be like for a bomb squad guy to defuse a time bomb. Now I’m much more comfortable with these things, but as always, I’m extremely cautious.

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I don’t think that I have ever heard “the pop” when discharging monitors. Most of the games I have worked on have sat for months and months before I perform a cap kit. I was glad that I knew the proper way to discharge the capacitors either way. It is pretty nerve racking…this is not how I want my obituary to read;

Man dies from 80’s arcade game – We all loved him, but little did we know Pac-man would truly kill him.

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