Dolphin Chowder
New member
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
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
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
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