Xybots K7000 help please

Dolphin Chowder

New member
Joined
Jul 24, 2016
Messages
16
Reaction score
0
Location
Wisconsin
Hello all. This is my first attempt at fixing up an arcade machine. I got a Xybots. When I bought it and turned it on the monitor just had a yellow color and had big flickers constantly and buzzed pretty loud. I have been reading a lot of these forums for weeks now and watching youtube videos and felt like I was up to the task of trying something to fix this. I ordered a repair kit from bob roberts to replace the flyback, hot, fuse, and cap kit.

Even though this was my first time doing this, I feel that it went okay, accept that the monitor still doesn't work. lol. After replacing all those on the board it now is still just a yellow screen but has no flicker at all and the buzz sound is much more acceptable.

A few things that I have questions about when I was replacing those elements on the board. First the flyback. When replacing the flyback the old one was all cracked open so it definitely needed to be replaced. The small red wire that comes from it was originally attached to a pin connector that went on the neckboard. I didn't have a new pin connector so I just soldered it to the pin. Is that okay to do? Secondly the large red wire that comes out the flyback goes into the white connector on the neckboard. I couldn't get that open for the life of me to get that wire in there so I just spliced/soldered it to the old wire outside of that connector. Is that okay? Do those connections need to be covered/insulated at all? or can they be left open?

Second is the HOT replacement. When doing this the old HOT was sort of loose on the heatsink. I took it off and polished up the heatsink. Cleaned off the mica insulator. I couldn't test the existing HOT because I can't figure out my multimeter to test it. I have an analog one and can't get a reading in the ohms setting on the new or old one. I don't think my multimeter can test diodes. Anyway. I put the new one on since I had it there. I applied silicone thermal grease in this fashion: heatsink - thermal grease - mica insulator - thermal grease - HOT. Then I screwed it on tight and soldered it nicely. Did I miss anything here?

Lastly is the cap kit. Several issues here. It definitely looks like someone has done some re-soldering on this board as there is lots of excess flux on the bottom of the board in spots and certain solder joints look shiny and new versus dull, flat looking other ones. However no caps have been replaced before, all originals in. I went to work popping out caps and replacing them one by one. Cap C50 was nasty. Yellow goo hardened on all over the case and running all over the board and hardened on. I replaced the cap but didn't scrape the hardened goo from it off the board. Does this stuff have to be removed? Does it cause a short at all? If so, how do I get it off without damaging the board and components? Next I get to C204 on the neckboard. This is a non-polar cap but bob roberts sent me a 4.7uf 250v replacement that clearly has the lines going down it that would indicate a negative side. So what I did was but the negative side into the ground socket on the board. Is that okay?

When I initially hooked it up and turned it on, I flipped the switch and just watched the board for about a minute. no smoke, no sounds, and the tube audibly was turned on. I was excited. But then I went and looked at the screen, it was black. My heart dropped. I twisted the flyback screen button up and the screen came to life (just a full screen of yellow though). When I did this I heard about 4-6 small popping cracks coming from the board area. I quickly looked in to try and see where it was coming from but couldn't identify the place and there was no smoke, no smell, and the screen still worked so I assumed it wasn't an issue. I turned off the power and double checked all of the caps and they are all in correctly. I checked all my wires to see if they were correct with my pre-pictures and the video in wires were off by one. So i popped that on correctly and excitedly turned the monitor back on but still just yellow on the screen-no flickers any more so I did make some progress :). Not knowing what I am doing I decided to twist each pot and see what happened. As I did they all did exactly what they were supposed to do. The neckboard ones changed the screen to blue or red or green as they should. I turned it back to yellow. The main board ones moved the screen up and down, left and right, and sized it like they should. I just get no video picture, just a yellow screen.

Does anyone have any advice on things to check or do? Is the video wires bad?

Other notes to help you offer recommendations: The game turns on, the audio works, I can manually put in credits for player 1 and 2 and start the game, shoot and zap with them. Just a yellow screen though... Also, when removing the old solder that stuff is tough to get off. I had to heat it a lot to get it to melt. I hope I didn't damage any of the board components by getting the board too hot removing solder. I mean sometimes I was holding the iron on for about a minute and it was still not melted. (maybe my iron sucks).

The reign of Zybot oppression on the human race needs to come to an end. Please help me get this thing working so I can save the humans from being neutralized! :O
 
Last edited:
first off BR cap are the low grade caps and if you need quality ones check out my site 100% nichicon 105c.

your flyback soldering to the ground pin is okay but you should have soldered and shrink wrap to the original connector.
next the larger red wire i personally wouldn't splice that i would install into crt socket (post picture of your socket and i can see why you can't open it).

next your HOT installation sounds fine just make sure you are very liberal on the thermal Non conductive paste.

lastly C204 is not a non polar cap ( you must have an original ceramic disc cap) and when switched to a polarized cap the ground (-) lead of the cap should be facing the white crt socket. (my cap kit instructions covers this for the beginners).

one thing you didn't mention is reflowing solder. i would recommend removing all solder from the input header pins and reflow new solder on them and then check.(my instructions on cap kits covers this also.)
 
Last edited:
K7000's are notorious for lifting pads, when removing solder. Holding any iron on them too long, will burn them off, then you'd need to make jumpers for them. Big advice from a lot of KLOVers here, apply a little bit of new solder, to the old solder you want to remove. It helps lower the melting point, so that your iron is not on the pad too long. Plus all of the other good advice mentioned above :)
 
Okay I got to work this morning...

Flyback - I undid the solder on the ground pin and soldered it and shrink wrapped it to the original pin connector. I also was able to pry open the crt socket and attached the cable right into there. The only problem is when I did this I accidentally broke off a leg on Green Cutoff Pot. Do you know what pot I should order to replace this? For now I just soldered the leg back together. I tested for continuity so it seems to work temporarily until I get a new one.

I reflowed the solder on the header pins and video input pins. As well as a few other places that I thought might be cold solder joints.

I attached pictures of C204 to make sure its in correct. Also a pic of the C50 yellow goo on the main board.

After doing these things, I get the exact same results. Plain yellow screen. Any thing else to check?

The Xybots continue to reign...
 

Attachments

  • C204.jpg
    C204.jpg
    196.8 KB · Views: 10
  • C50 Yellow Goo.jpg
    C50 Yellow Goo.jpg
    202.7 KB · Views: 14
Okay I got to work this morning...

Flyback - I undid the solder on the ground pin and soldered it and shrink wrapped it to the original pin connector. I also was able to pry open the crt socket and attached the cable right into there. The only problem is when I did this I accidentally broke off a leg on Green Cutoff Pot. Do you know what pot I should order to replace this? For now I just soldered the leg back together. I tested for continuity so it seems to work temporarily until I get a new one.

I reflowed the solder on the header pins and video input pins. As well as a few other places that I thought might be cold solder joints.

I attached pictures of C204 to make sure its in correct. Also a pic of the C50 yellow goo on the main board.

After doing these things, I get the exact same results. Plain yellow screen. Any thing else to check?

The Xybots continue to reign...

a yellow screen usually means your missing a color which could be pots bad or dirty or transistors(Q1,Q2, Q3 main board or Q201,Q202, Q203 neck board) (could even be a tube).

the PCB is filthy dirty and could have used a run through a dishwasher and the brown stuff is probably the old glue and not something oozing out of an old cap.
BTW: your caps should sit tight to the pcb or as close as possible and those are richey caps which are a much lower hour/grade caps then the nichicon we use in our kits.
 
Last edited:
How do you check pots to see if they are okay? Also how do you check those transistors to see if they are okay?
 
Update: So I only had an analog multimeter that doesn't test diodes. So I went and bought a digital multimeter that can test diodes so I could test those transistors.

All of the transistors on the neckboard tested good Q201, Q202, Q203. All of the transistors on the main board tested good Q1, Q2, Q3.

I still don't know how to test the pots. I ordered all replacement ones for the neckboard. Once they get here I will put them in.

Any other thoughts to check?
 
Update: So I only had an analog multimeter that doesn't test diodes. So I went and bought a digital multimeter that can test diodes so I could test those transistors.

All of the transistors on the neckboard tested good Q201, Q202, Q203. All of the transistors on the main board tested good Q1, Q2, Q3.

I still don't know how to test the pots. I ordered all replacement ones for the neckboard. Once they get here I will put them in.

Any other thoughts to check?

BTW: i stock almost all the pots on the board and remotes. to test them you use the ohm setting.
 
Okay. So basically you are just testing for continuity to flow through the pot? Do they need to be out of circuit to test this or can they be in the board?
 
Okay. So basically you are just testing for continuity to flow through the pot? Do they need to be out of circuit to test this or can they be in the board?

one probe on the wiper (2) and the other probe on pin 1 or 3 and turn the pot and your meter should go from almost 0 to the rated value of the pot. if you have 1 and 2 then if you test 2 and 3 it should be reading the opposite of 1 and 2. (in other words if 1 and 2 are going up in ohms then 2 and 3 will be going down and if 1 and 2 are going down then 2 and 3 are going up in ohms.) i hope this makes sense and i always test out of circuit so nothing else could effect your readings.
 
Update: So I replaced the pots on the neckboard. When I got everything hooked up I got the same result, just a plain yellow screen.

I then decided to try something else. I have a aquajack machine that doesn't work. The powersupply has issues. But it has a k7000 monitor in it that also doesn't work. So I thought I would try plugging the board that I have been trying to fix into the tube of that monitor. When I did this and got the game hooked up to it I get a solid blue screen.

I also get just a plain blue screen when the rgb cable from the game is not hooked into the monitor. Not sure what to test next.

Any thoughts?
 
i would personally work on one at a time because using a known non working monitor to test another known non working monitor you will end up chasing your tail. all monitors at that age should have new caps/reflow and that should be a starting point.
 
Back
Top Bottom