sf2 arcade – Ussher Press Daily

K7000 Chassis Repair: Installed a cap kit, new flyback, and new HOT

If you’re just joining us, a few weeks ago, I got a free, yes, free, Street Fighter II: Champion Edition arcade machine. I turned it on and found there was no sound and the screen was all green. Since then, I’ve determined the original arcade board (the PCB) was bad. However, the screen remains green, so I’ve been doing research to find out what exactly I need to fix on the CRT monitor to get it working again.

My monitor chassis is a Wells Gardner K7000 and on the advice of several people who have worked on monitor repair before, I was told to replace the capacitors, the flyback, and the Horizontal Output Transistor, i.e. the HOT.

Over the course of two late nights, I made the repairs. (Boy, I learned a lot. I’ll have a separate blog post on some tips for replacing the flyback and caps.) I put the monitor chassis back in the arcade machine today to see the results of my hard work.

Here she is after getting a new flyback, caps, and HOT. I cleaned up the PCB and wires as well, so she’s looking real clean:

The good news is nothing blew up. I can also adjust the the screen enough that I can actually see some gameplay! The flyback is working much smoother. The old one had high pitched hiss. When compared against the YouTube video I took of this a few weeks ago, you can see that there are no more wavy vertical lines on the right. I suspect the replaced capacitors fixed this up.

The bad news is that it’s still green and still has horizontal lines. 🙁 Actually it’s green with hints of blue. If I crank up the brightness or contrast, I see even more blue. This was what I was seeing before the repairs as well.

Here are a couple of pics:

In the end, I am happy with my work doing the cap kit and flyback repair. I can’t believe I actually did it. However, there’s still more work to be done, so stay tuned.

Monitor Chassis Removed

After a lot of reading up on safety precautions and watching a lot of YouTube videos on CRT monitor discharging, I took the plunge.

First, I made a discharge tool. I took a flathead screwdriver and soldered an insulated wire to its shaft. I took the other end of the wire and attached an alligator clip to it. I soldered this end as well. I wrapped both soldered connections in electrical tape. I neglected to take a photo of the thing, but here’s a diagram of what it might look like if you used alligator clips on both ends of the wire:

I delayed discharging the monitor for as long as I could just because I was chicken. Finally, in the middle of the afternoon, I figured I should do it. I clipped the alligator clip to the frame, put my free hand in my pocket, and then slowly inserted the screwdriver tip under the anode cup. I have to admit it was frightening.

I slowly inserted it closer to the leads of the anode and next thing you know, I can feel it hitting the leads. And yet, no pop. That was it. I discharged the monitor uneventfully.

I was a bit underwhelmed and also a little scared that maybe I did it wrong, so I tried again. Still, no pop. I decided to go for it and pry the anode out using the screwdriver. After a few seconds, I got it off. Nothing to it!

I made contact with the hole at the top of the tube to verify there was no more charge. I found none at all, so that was it. The last time I turned on the monitor was a week earlier, so I suspect it discharged itself in that time. I’ve heard that the Wells Gardner K7000s don’t really hold a charge for very long, so that’s likely part of it. Anyway, it was overall much easier than I thought. As this page says,

It’s a little frightening the first couple of times, but the thrill wears off.

In the end, here’s what the cabinet looks like without the monitor chassis:

Here’s what the chassis looks like after removal:

A better view of it:

The next step is to inspect the board, fix bad solder joints, replace the flyback, and replace the capacitors.

What you get when you buy a Wells Gardner K7000 Repair Kit

I recently bought a K7000 monitor repair kit from The Real Bob Roberts. I sent in a check to Bob and a few days later the kit was in my mailbox! The service was quick and friendly. I highly recommend it. If you are thinking of getting it or something similar, here’s what you get.

A nice little package awaited me when I got home.

What’s in the box? Well, not Gwyneth Paltrow’s head. Instead, you find a load of packing peanuts and a smaller box.

Open up that box and you’ll find a cap kit and a flyback transformer.

The cap kit contains several capacitors for the K7000, a horizontal output transistor (HOT), a fuse, and some instructions. In the package is also a little label where you can note the date of the cap kit repair. Nice touch!

Finally, here’s the flyback transformer in all its new, bright red glory.