Alva Amusement chassis 25"

r3m

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hello,
I have decided to go the route of Alva Amusement's 25" chassis for a TV I found. The tube number is A63AGD01X which is from a 25" Zenith tv. I called them up and told them my tube model number and said that I'll be needing a A25HR chassis. I read in older posts that it's going to be a wei-ya chassis. I haven't really found any information on what plugs on the chassis and in the arcade machine I'll be needing to change. I have decided to hold off until I move into my new house rather than taking the chance of moving the arcade machine to my new house with the new tube and chassis installed to avoid problems and wasting away the 30 day warranty which will be used in moving. My questions are, What will I be needing to change in my cabinet and on the chassis? I know the horizontal/vertical connectors as well as the 2 prong power cord. Is there any picture tutorial I can maybe get an idea from? Also it seems on my newer tv tube I got that the wires are soldered onto the horizontal/vertical pins with shrink wrap and see no spot where I will connect my new wires from the chassis I'll be getting. I'll post a pic in about 10 minutes or so of what I'm talking about.

Thanks in advance!
 

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Fitting the wei-ya 825HR is not a super difficult job. It should look great on your Zenith tube. I have one running on the same tube, the quality is outstanding. You might run into some mounting issues. This is easily solved by strategically using some zip ties from holes on the bottom of the chassis to holes on the platform. Make sure you face the flyback towards the back for easy adjustment.

If you haven't already done so, make sure to read up on how to properly discharge the tube at the anode before anything.

For this chassis, there will be a couple things you need to do:
1) Power cord- this chassis actually comes with a power cord and plug on it. DO NOT PLUG IT IN AN OUTLET. If you have soldering skills, unsolder this plug and transport your old power molex from your old chassis to this. Otherwise, you can strip and splice the cord with your old connector using some butt connectors. Also, this chassis requires an isolation transformer. Its very likely your old monitor used one, but just confirm theres one in the cab to be safe.

2) Yoke wires - The box includes a new yoke connector, i've never actually used one they supplied, i just use the existing wires. The yoke wires from your old chassis might not go in the same order as on this chassis. You may have to cut the yoke connector with the 4 wires in half at the center and reverse a pair to get the picture orientation correct. You can adjust the yoke wires without discharging the chassis, just make sure its turned off and you're careful.

3) Signal wires - The connector for the signal wires for this chassis is unique (and it comes in the box), so you will need to do some splicing here. Best way is to solder and heat shrink your R, G, B, video ground and sync wires to the new connector. If you don't have soldering skills or tools, the next best thing is to get a screw terminal block, i use these for testing and they work great.

4) Chassis ground - the black ground wire that connects to the frame (usually on the flat ground that stretches to the corners of the frame) will need to be spliced possibly if it does not already have a small single pin connector on it. This runs to the neck board. It is imperative this connection is very solid. The chassis will come with a brand new wire you can splice to the old one.

5) The degauss connector will fit without changes and has no polarity.

When you have got all that done, the only thing left is to attach the neck card and anode cap. Visually confirm the prongs from the cap are in the anode! If they do not go in all the way, you can expect your picture on your screen to be a few inches high.

Beyond that, the first time you power it on you might not see anything. This is because sometimes the flyback screen voltage pot is turned all the way down from the factory. The focus will probably be out too. These can be changed with the monitor running. Use a tool and be very careful.

Good luck.
 
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Sorry for the "thread jack" but question for Ken about this chassis that may benefit the OP:

One of the issues on these is the width is more than often too wide for most tubes. The solution is to change out cap C912. I've done some random swapping with fairly mild success. Do you have any recommended values for this cap to bring it down the width a good inch or so?
 
I have not worked on the 825 or 826 chassis before. The schematic shows it to have a (N)arrower and (W)ider jumper to set the range of the width. There is also a horizontal width pot.

I know in the past Alva has sent people the 826 chassis (for 26 and 27 inch tubes) to use on 25 inch tubes and gotten way too big of a picture. The 825 chassis is for 25 inch tubes
 
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Yea, even with the width jumper set on narrow, its sometimes still too wide. The width coil is semi-tamper proof, they have inserted a piece at the top that prevents you from adjusting it. I've read of some folks removing it and making adjustments anyway.
 
Thanks for all of the information guys! I thought she said A25HR. Maybe that's why I couldn't find any information on the chassis? lol I'm trying to think whether I should be cutting wires or soldering in those new male molex connectors. I'm not the greatest at soldering. I can do it though. Which would you guys do? Keep the cabinet all original or the chassis? I am thinking that desoldering stuff on the chassis would void my 30 day warranty. I am feeling a lot better & confident about this project now knowing that srarcade80 has the same tube and chassis and it turned out great. And thanks a lot KenLayton. I have read a lot of older post with your input in older threads and appreciate what you are doing to help all of us esp with these chassis's. Once this is a done deal with the house I will keep this thread updated with any problems I have or success. Anyone feeling that they should put any extra info in here feel free to do so.
 
@KenLayton I got a question. I was doing some reading before I went to work last night and I seen that you said Midway cabinets had a problem with the wiring of the isolation transformer. Is there anything I should do with the wiring before I pop in a wei-ya chassis? Reference: http://forum.arcadecontrols.com/index.php?topic=62023.0

Thanks
 
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Midway Mortal Kombat and NBA Jam cabinets had ALL the 120 volt AC devices wired to the output of the isolation transformer. Only the monitor should be connected to the output of the isolation transformer.
 
Well now I know in case I have to do something wrong with my MK(SURE HOPE NOT). I am going to be putting the wei-ya into my Killer instinct cab. There is no wiring changes I have to do? I don't want to end up like that guy with a cloud of smoke and a messed up brand new chassis.

Sorry to be a nuisance.
 
Well now I know in case I have to do something wrong with my MK(SURE HOPE NOT). I am going to be putting the wei-ya into my Killer instinct cab. There is no wiring changes I have to do? I don't want to end up like that guy with a cloud of smoke and a messed up brand new chassis.

Sorry to be a nuisance.

KI and MK are both Midway cabs. I haven't checked inside my KI2 cab but I believe they might be wired the same.
 
KI and MK are both Midway cabs. I haven't checked inside my KI2 cab but I believe they might be wired the same.
Ya I think so as well. MK2,MK3,MK4,KI1,KI2,NBA Jam and I'm sure some others. But I wonder when they fixed this little problem if at all. I understand what's being said by Ken but really how would you even fix that??
 
I understand what's being said by Ken but really how would you even fix that??

Take all of the other wires that are hooked up to the ISO and splie them or use a distribution block to wire them into the 115 volts that's coming from the plug/extension cord. I have the back off of my KI2 I'll take a peek and see if I can snap a pick of where you can connect the other items.
 
Ok sounds great. I'll take a pic of mine when I wake up. Just got home from working midnight shift. We can see If we have the same setup.
 
Well here are the pictures. from what I can see the purple wire is going to the chassis, bill acceptor, the marquee light. I guess that's what were talking about here with the isolation transformer?
 

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No one knows if anything should be changed or not with the wiring and the iso transformer? Sorry for the bump
 
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Well I ended up getting the picture on the tube and pretty close to the right size but after changing the width cap there is a resistor that gets super hot in seconds. Can't hold my finger on it more than a second without getting burned really bad. It also started shitting down etc. The tube is on the side right now not being used actually. Wish I could figure out what to do with it really.. =/
 
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