PSU and light rewiring SNK Candy 25

[Moonwalker]

I am planning to exchange the PSU in my SNK Candy 25 since it has a crappy one installed and the wiring is a total mess. Would like to exchange it for a standard arcade PSU and would like to ask some questions.

First of all, how to proceed? My thoughts until now are to measure the +5v -5v and +12v with a multimeter. Where would be the best place to measure those? Next the main voltage, I think that should be the easy part since I just have to connect ground and voltage and can connect them to the PSU directly right? Is it important to find out which is ground and voltage or doesn´t it make a difference?

After knowing which voltage everything has it is just wiring those to the screws of the PSU as far as I understand.

Until here I hope my line of thought is correct.

Next the flurouscent bulb. It has a 2 pin connector I cannot plug in nowhere (I am quite sure the PSU which is inside now is not original). As far as I understand I can just cut off the connector and wire it to the main voltage and ground on the PSU. Not sure if this makes sense though...

I would be very grateful if somebody would help me to confirm if my thoughts are correct and give me some hints maybe. Don´t want to toast my cab

Thanks in advance!

[nem]

My thoughts until now are to measure the +5v -5v and +12v with a multimeter.

Not sure why you're measuring if you're set on replacing the old PSU. Unless you don't know which is which on the old PSU?

Next the main voltage, I think that should be the easy part since I just have to connect ground and voltage and can connect them to the PSU directly right? Is it important to find out which is ground and voltage or doesn´t it make a difference?

With AC voltage one is live (L) and the other is neutral (N). It doesn't matter which you way you connect the two. The third wire (if there is one) is earth ground.

After knowing which voltage everything has it is just wiring those to the screws of the PSU as far as I understand.

Yes

Next the flurouscent bulb. It has a 2 pin connector I cannot plug in nowhere (I am quite sure the PSU which is inside now is not original). As far as I understand I can just cut off the connector and wire it to the main voltage and ground on the PSU. Not sure if this makes sense though...

Most likely it's for mains voltage, yes.

Take lots of pics and post them here before you do anything!

[Moonwalker]

Cool, thank you very much!!!

Not sure why you're measuring if you're set on replacing the old PSU. Unless you don't know which is which on the old PSU?

Right, I don´t know which is which
Will post pics tomorrow.

[Moonwalker]

OK, so here the pictures:




This is the crap PSU, fuses and the test, service and power switch.
Not sure how to rewire those. Also I don´t know why one fuse is not connected and the cable is cut off (purple one).



Here are the voltages. Don´t know which one is which, any clue where I should measure?
I also don´t know where the main voltage is.



This is where the electricity cable is going out. Also the ground for the light (green wire) is connected there. That is, if the green wire is the ground. The white cables there are connected to the plug of the light.




This is the connector coming from the electricity out and ending in the 2 pin plug for the light.

How should I proceed?

[nem]

The two wire lead from the fluorescent light will be an AC wire, so one lead is live and one is neutral. Double check that it ends in a ballast to make sure.

The PSU should be easy to figure out. You have four connections on that thing. Where do the two white wires that are in a black sleeve and in the top most connector go to?

The next connector most likely has AC L (white), AC N (white) and earth ground (green).

The bottom two connectors are for +5 and +12. Black wire is ground. You can now break out the multimeter. Set it for DC voltage, put the black probe on where one of the black wires come out from the connector block and then do the same thing with red probe on the yellow and red wires. If you're not getting anything on the multimeter, try to stick the probe in an angle. You have to touch the metal connectors inside the connector block.

[Moonwalker]

Great, thank you!

The two wire lead from the fluorescent light will be an AC wire, so one lead is live and one is neutral. Double check that it ends in a ballast to make sure.

So these should be connected to the new PSU´s main voltage right? What do you mean with ballast, ground? They are connected to the little box in the back of the cab where the cable comes out. visible here:

The PSU should be easy to figure out. You have four connections on that thing. Where do the two white wires that are in a black sleeve and in the top most connector go to?

They are connected to the PSU´s back part. Strange but seems of no importance.

The next connector most likely has AC L (white), AC N (white) and earth ground (green).

So these need to be wired to the new PSU´s main voltage an earth, correct?

The bottom two connectors are for +5 and +12. Black wire is ground. You can now break out the multimeter. Set it for DC voltage, put the black probe on where one of the black wires come out from the connector block and then do the same thing with red probe on the yellow and red wires. If you're not getting anything on the multimeter, try to stick the probe in an angle. You have to touch the metal connectors inside the connector block.

Got it, thank you very much!

I will start working on it on Sunday

[nem]

So these should be connected to the new PSU´s main voltage right? What do you mean with ballast, ground? They are connected to the little box in the back of the cab where the cable comes out.

That little box is a noise filter.

The ballast is the box that feeds power to the fluorescent light. It should be near the fluoro light.

Both the ballast and PSU will need AC (mains voltage).

So these need to be wired to the new PSU´s main voltage an earth, correct?

Yes, that's your AC input.

[Moonwalker]

Ah got it. Yes it goes to the ballast.

Thank you very much for your help. Gotta say it again, this forum is so great with only nice people - never had a bad experience neither trading nor see any trolls.

[Moonwalker]

OK, I took a nightshift and did everything according to my thoughts and your suggestions. The outcome was not very good resulting in toasting the fluruoscent bulb and not getting any picture. Sound is there though.

Yes, that's your AC input.

I wired everything to the new PSU and plugged the cable of the new PSU in. That resulted in a short circuit and the fuse for the wall socket went off. I then saw that I had the original power cable of the cab and the one of the new PSU plugged in. The original one was plugged in a wireless socket which was turned off though. I use that to not always have to open the cab to turn it on or off. I took the wireless plug off and put he fuse back, after switching the cab on again it worked partially. The bulb was on and I could see the +5V worked (I have a voltmeter on the Jamma edge). I had no PCB connected. The bulb seemed quite bright and shortly after there came vapors out of the light bulb and I sensed a nasty smell - the bulb was toasted. I took off the bulb cables and tried again.

Then I connected a PCB to test the cab itself. There was no picture, I put in a coin and I heared sound. The PCB power supply works and sound as well, but no picture. I then took off one ground cable because strangely the ground cable of the old PSU was cut off from the beginning and I wanted to make sure that this was not the problem. Nothing changed, so I connected it again.

Afterwards I checked the fuse of the monitor chassis which seems fine. The big component next to the fuse on the chassis was a bit lukewarm.
I really hope I only toasted the bulb and not the chassis.

Here some thoughts:

- I am confused that the ground was never connected to the PSU. Shouldn´t it have been a problem from beginning?
- Since there was no bulb installed when I got the cab I just ordered one and put it in. Not sure if it was the wrong one or the wiring was off.
- Of course I didn´t double check the ballast of the light bulb :/
- The new PSU is set to 220V. I bought an Egret 2 which was also changed to an arcade PSU and that one had a European plug with 220V as well, so I thought that should be fine.
- I am totally sure that the wiring of the +5 and +12 is correct. The rest should also be correct as far as I understand.
- The main voltage and ground goes to the little box in the back you mentioned is a noise filter.
- The power switch inside the cab does not work anymore. How can I get it to work again?

All in all I am totally clueless now...

Here some pictures:

The bulb (and ballast?)


The bulb with strange toastings...


Specs of the bulb


The newly wired PSU


The fuse of the chassis


The "lukewarm" component on the chassis

[Moonwalker]

EDIT: Sorry, doublepost...

[nem]

Ruh roh.

It's a japanese cab, so your chassis and ballast will run on 100V. You didn't connect these to 240V, did you? There's no transformer inside your cab, which means you must have had a separate step down transformer prior to this.

- I am confused that the ground was never connected to the PSU. Shouldn´t it have been a problem from beginning?

It's an earth ground. Not all power supplies are earth grounded.

[Moonwalker]

Ruh roh.

It's a japanese cab, so your chassis and ballast will run on 100V. You didn't connect these to 240V, did you? There's no transformer inside your cab, which means you must have had a separate step down transformer prior to this.

Damn, as I thought. I connected them to 220...
As I said the Egret 2 I bought was also connected directly to the 220V without a stepdown convertor.

What would you suggest to do next? Maybe the chassis fuse stopped it from getting damaged?

[nem]

The chassis fuse is probably a slow blow one which is why it looks it is still intact. The fuse in your wall is a fast acting one. If you have a continuity setting on your multimeter, you can test the fuse. Unfortunately, I would be very surprised if your chassis is still OK at this point.

Your new PSU will work on 100V, so start by connecting the cab back to the step down transformer. EDIT: make sure there isn't a separate switch on the PSU for 100V input.

The ballast might still be fine. What the ballast does is it limits the current going through the fluorescent tube. You put double the input voltage which means the output blew the tube.

As I said the Egret 2 I bought was also connected directly to the 220V without a stepdown convertor.

This is different as you have a separate transformer inside your Egret 2.

[Moonwalker]

The chassis fuse is probably a slow blow one which is why it looks it is still intact. The fuse in your wall is a fast acting one. If you have a continuity setting on your multimeter, you can test the fuse. Unfortunately, I would be very surprised if your chassis is still OK at this point.

Your new PSU will work on 100V, so start by connecting the cab back to the step down transformer. EDIT: make sure there isn't a separate switch on the PSU for 100V input.

The ballast might still be fine. What the ballast does is it limits the current going through the fluorescent tube. You put double the input voltage which means the output blew the tube.

As I said the Egret 2 I bought was also connected directly to the 220V without a stepdown convertor.

This is different as you have a separate transformer inside your Egret 2.

So next step would be to get a new fuse for the chassis and connect the psu set to 100V to the stepdown converter right?
I would need a japanese plug cable with three lines for it. Could you please confirm that I don´t need the original power cable of the cab anymore? I could then just cut that off and wire that one to the PSU and put that into the stepdown convertor.

If that fails, is the chassis still repairable? Would be difficult?

Damn! Thought about that before plugging it in but since the Egret could do it I thought this cab could as well... Such a stupid mistake! I really hope the chassis is still fine, just got it from Grant...

[nem]

So next step would be to get a new fuse for the chassis and connect the psu set to 100V to the stepdown converter right?
I would need a japanese plug cable with three lines for it. Could you please confirm that I don´t need the original power cable of the cab anymore? I could then just cut that off and wire that one to the PSU and put that into the stepdown convertor.

If that fails, is the chassis still repairable? Would be difficult?

Damn! Thought about that before plugging it in but since the Egret could do it I thought this cab could as well... Such a stupid mistake! I really hope the chassis is still fine, just got it from Grant...

The fuse you have in your pic looks intact. If it had blown the wire inside would be snapped and the glass tube would be black or grey.

You can use a two pronged japanese cable or three pronged one if you have one. Don't worry about the earth ground, you won't blow anything without it being there. Remember it wasn't properly grounded before.

I'm sure the chassis is repairable. You're not the first one to plug in one of these to 240VAC. However, more than likely it will have to go back to Grant.

[Moonwalker]

So next step would be to get a new fuse for the chassis and connect the psu set to 100V to the stepdown converter right?
I would need a japanese plug cable with three lines for it. Could you please confirm that I don´t need the original power cable of the cab anymore? I could then just cut that off and wire that one to the PSU and put that into the stepdown convertor.

If that fails, is the chassis still repairable? Would be difficult?

Damn! Thought about that before plugging it in but since the Egret could do it I thought this cab could as well... Such a stupid mistake! I really hope the chassis is still fine, just got it from Grant...

The fuse you have in your pic looks intact. If it had blown the wire inside would be snapped and the glass tube would be black or grey.

You can use a two pronged japanese cable or three pronged one if you have one. Don't worry about the earth ground, you won't blow anything without it being there. Remember it wasn't properly grounded before.

I'm sure the chassis is repairable. You're not the first one to plug in one of these to 240VAC. However, more than likely it will have to go back to Grant.

****! I will try it with the fuse beforehand. Thanks for your help...

[Moonwalker]

GOOD NEWS!!! I changed the fuse and everything is fine. Thank god I did not connect the chassis to the PSU in the beginning, but it was connected to the original cable and got a short circuit when I had both cables inside and turned it on. You can see the connectors for the electricity of the chassis here.



Luckily the architecture of the wiring is quite strange so that the only damage was the lightbulb.

Thanks to Grant I found the correct fuse on the chassis, which was blown. Put a new one in rewired everything again and it works perfectly now! Just have to wait to get a new bulb and the light will also shine

I have 2 other questions.

The ground wire is not connected at all right now. Is it ok to keep it like this? Also for the bulb? The ground of the bulb was connected to the back of the cab visible here (the green cable).



Finally I would like to exchange the speakers of the cab. Can I just measure the dimensions and get car speakers? Do I have to take care of anything or has anybody suggestions for good speakers?

Thank you very much Nem and Grant for your help!

[nem]

Success! You lucky dog, you!

Basically everything that's metal should be earth grounded (I keep repeating earth, because earth and DC ground on the PSU are things you don't want to mix).

For speakers you want to make sure your replacements are the same ohm.

[Moonwalker]

Success! You lucky dog, you!

Basically everything that's metal should be earth grounded (I keep repeating earth, because earth and DC ground on the PSU are things you don't want to mix).

For speakers you want to make sure your replacements are the same ohm.

Thanks!

I would like to get the power switch to work again. Test and Service works, but the power switch not. Any ideas?

[nem]

The power switch is probably a double pole single throw switch, meaning it has two inputs and two outputs. One input and one output is for live (L), the other set for neutral (N). The AC line should come straight from the noise filter to the inputs of the power switch and from the outputs of the power switch they will separate into three AC lines: one for the PSU, one for the monitor and one for the ballast. This way you will cut all power from the cab.

Also, If you wire the power switch haphazardly you will short circuit it, so make sure which poles are pairs. It doesn't matter which side is input and which output as that will only affect the orientation of the switch (ie. which side is pressed for ON).

EDIT: nevermind, it looks like the switch is a single pole single throw. So you need to wire either L or N to it.