Centipede restoration - My first - There will be plenty of pics

Arcade Collecting > Restorations & repair

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bperkins01:
Its been a while since I've updated this entry.. I've made incremental progress on the K4600 monitor.

I picked up a dead chassis so that I could compare and potentially swap components, etc.
One thought I was having was that the neck board was giving me issues in general. Earlier in this thread I mentioned to check, double check and check again for broken off parts. Turns out there were 3 tiny capacitors on the neck board broken off.

Look at C408, C409, C410. These ones are not even shown on the schematic that I have, but they are on the parts list. I swapped the neck boards and it appeared a little color bleeding went away.. But nothing significant.

On the inability to shut off color guns with the TPG, I figured out why that was an issue. My K4600 uses the P305 interface card which doesn't have pull down resistors like nearly all of the other cards:

You can see the 3 resistors connected to the RGB pins 1,2,3 on the right. I added the resistors to my card so that I can turn off the individual guns. When I was turning off the guns with the TPG, the voltage was floating and the guns just made the entire screen the color I was turning off. One more thing learned...

During this Learning to fix crt phase - I've watched many Randy Fromm videos. He has a book - Randy Fromm's Big Blue Book of Really Great Technical Information that I picked up..

One thing I thought I understood - but not well enough was this:
The alignment of the convergence rings on the neck of the tube.

My swapped tube had an all in one unit of yoke and rings. I had to use the K4600 yoke and rings. Turns out the geometry of the swapped tube didn't allow for the proper alignment The gun gap was in a position that the 2 part yoke/ring combination would not line up vs the one part original. I had a LOT of practice aligning and un-alignable configuration..

I have another donor tube to experiment with - I'm pretty sure I can get them lined up and I'll try again..

All that said - this chassis probably was not the original since it had Pacman and 1942 burned into the tube. I've been watching Facebook Marketplace and came across a guy who was selling 3 arcade monitors.

One of which is impossible to believe: BTW - I did not know this is what I was going to pick up.. The owner never sent the model# picture..

This is a brand new, never used, K7200. Manufactured in 2003. If you look at the power wires - they have never seen a connector. It came as is - I'm guessing the guy who sold it to me took it out of a box or bag or something.. I did a quick test on the TPG to make sure it fired up and finished the monitor portion of the Centipede machine.

My wife tells me I lead a charmed life when this sort of thing happens.. I'm not disagreeing on this one..

Mike A:
:applaud:

jennifer:
Congratulations, That is Awesome!...On that other tube, Convergence is a big deal, some claim to do that by feel, and eyeballs, But they lie, Personally I use a Klein Convergence scope with excellent results, You can actually see the convergence and purity, Not perfect mind you, but certianly good enough for the quality control inspectors on this side of the tracks,, If you go sourcing one they make different ones for different resolutions (Diddnt know that when I got mine, and just lucky) since Jenn is not a rich girl, that could have gotten spendy buying all 3...But luckily it has already all worked out for you on this project, That is just a little sweetie.

bperkins01:

--- Quote from: jennifer on March 22, 2020, 02:13:37 pm ---Congratulations, That is Awesome!...On that other tube, Convergence is a big deal, some claim to do that by feel, and eyeballs, But they lie, Personally I use a Klein Convergence scope with excellent results, You can actually see the convergence and purity, Not perfect mind you, but certianly good enough for the quality control inspectors on this side of the tracks,, If you go sourcing one they make different ones for different resolutions (Diddnt know that when I got mine, and just lucky) since Jenn is not a rich girl, that could have gotten spendy buying all 3...But luckily it has already all worked out for you on this project, That is just a little sweetie.

--- End quote ---

This?
https://www.kleininstruments.com/convergence-gauge

If I could get it remotely close with the test pattern generator I'd be happy...
I have a few monitors to work on now, once the game restorations are done.

Haven't started the 'Asteroids' restoration thread yet..

opt2not:
NOS monitor?! You lucky sonava... :lol

Nice get, this restoration just kicked up a notch in quality now. And if/when you re-sell, you can definitely ask for top dollar!

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