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andrewb said:
You want to set the DMM to the next highest voltage range setting above what you want to measure. So 20V in this case.

Also, be aware there is a +SENSE and -SENSE test point. You want the +SENSE one. You can also use the positive (+) side of the C1 cap on the AR, instead of +SENSE. Either will work.
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Tested on +SENSE thankfully. I have it at 5.03 at the moment. I read somewhere that should be fine?

Next up set to AC and test 10.3V?

Then next up is to test the Centipede itself for +5 and -5.. need to find an image of where I do that on the board.

I'm going to post more pics of the inside in a second.
 
Take the game board out of the cab, and look at it under a good light. There are test points for all voltages, and they are labeled. +5, +12, -5, +22,-22,+15, -15, and -30V. Use any GND test point on the game board when you measure. (Always use a ground that is on the board you are measuring voltages on, whenever you are testing voltages.)

All of the test points above are within a few inches of the side of the board that the edge connector plugs onto.
 
For now I adjusted the pot again. It measures 4.99 and 5.00.. is that good or shall I adjust it up a slight notch?
 
Here's another pic of the cabinet inside.. as you can see super clean:

insideclean.png

That ground wire was hanging there. It's the green wire hanging in the middle. I wonder where I attach that.. or just pick a screw? Those power wires as you can see have been fxxked with at some point.
 
SourCream said:
For now I adjusted the pot again. It measures 4.99 and 5.00.. is that good or shall I adjust it up a slight notch?
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On the AR, or the game board?

When you check it on the AR with the game board unplugged, you're just doing a rough check to make sure it's 5V, and not anything wildly different (like 10V or 1V, which would mean there's a problem with the AR, in which case you don't want to plug the game board in). You can set it to 5.00V on the AR, but this is just temporary, as the voltage on the game board is what matters.

There is always some voltage loss in the wiring and connectors between the AR and the game board. So if you set it to 5.00V on the AR, it will be up to half a volt low when you measure it on the game board. That is normal. But you want to turn the pot up so you end up with 5.00V on the game board.

Realistically it can be anywhere between 4.75 and 5.25V on the game board and the board will still work. But you want to aim for 5.00V when you set it. If it's off by a few hundredths either way, that's not a problem. But it's good to set it as close to 5.00V as possible, because if you test it in the future and it's significantly off from that (like by more than a tenth of a volt), you know something has changed. But if you clean and DeOxit all of the connectors, it should stay pretty much where you set it.
 
Here's a pic of the Centipede PCB.. I see a spot marked +5V up top near the red light.. by the way that red light comes on.. I see a spot marked GND all the way on the bottom.. I do not see the -5V so far.

PXL_20240517_041216540.jpg
 
andrewb said:
On the AR, or the game board?

When you check it on the AR with the game board unplugged, you're just doing a rough check to make sure it's 5V, and not anything wildly different (like 10V or 1V, which would mean there's a problem with the AR, in which case you don't want to plug the game board in). You can set it to 5.00V on the AR, but this is just temporary, as the voltage on the game board is what matters.

There is always some voltage loss in the wiring and connectors between the AR and the game board. So if you set it to 5.00V on the AR, it will be up to half a volt low when you measure it on the game board. That is normal. But you want to turn the pot up so you end up with 5.00V on the game board.

Realistically it can be anywhere between 4.75 and 5.25V on the game board and the board will still work. But you want to aim for 5.00V when you set it. If it's off by a few hundredths either way, that's not a problem. But it's good to set it as close to 5.00V as possible, because if you test it in the future and it's significantly off from that (like by more than a tenth of a volt), you know something has changed. But if you clean and DeOxit all of the connectors, it should stay pretty much where you set it.
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Yes I have the game board (and I think the monitor) unplugged. I was testing +5V to the AR-II board. Good I have it set. Next I was going to test 10.3V. The other thread said set it to AC. I have not done that yet. I closed up my garage for the night and will begin there tomorrow.
 
SourCream said:
Here's a pic of the Centipede PCB.. I see a spot marked +5V up top near the red light.. by the way that red light comes on.. I see a spot marked GND all the way on the bottom.. I do not see the -5V so far.
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Slide the board out of the cabinet, and look at it under a bright light to find the other test points.

They are there.
 
andrewb said:
Slide the board out of the cabinet, and look at it under a bright light to find the other test points.

They are there.
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I will check the 10.3V tomorrow and slide the board out.

Do you recommend I buy 91% isopropyl alcohol and clean the board at all tomorrow? Or as my friend says it looks pretty clean don't mess with it.
 
Follow andrew's recommendations and make sure your power is sorted out and clean EVERY connection in there.

DeOxit is a specific combo of stuff (naptha, oleic acid, and mineral oil if I remember correctly) and nothing else is an adequate substitute.

I use only denatured alcohol on any of this stuff otherwise, but I'm picky.
 
SourCream said:
I'll try and find Deoxit. Amazon won't ship it here. Maybe Digikey will. Is Deoxit D5 what I want?

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I gave you an ebay link to exactly what you want in post #11. It's half the price of Digikey.

If that seller won't ship to Canada, just find another on ebay who will.

You don't want to clean the board with isopropyl. If you want to wash the board, go to the Advanced Search page, type in 'Greased Lightning' in the keyword field, and 'andrewb' in the Posted By field,then press Search.

That will find you dozens of posts by me in threads about cleaning boards. Read lots of them.

If you want to clean a board properly, you want to wash it first per above, then remove all socketed chips, clean the inner and outer faces of each leg with a fiberglass pen or a Dremel wire wheel (which is what I use).

Then spray some DeOxit in a small jar, paint some on the chip legs with a small art paintbrush, then reseat the chip a couple of times. Repeat for all socketed chips.

That will remove the 40 years of grime and oxidation that is built up on the chip legs, which causes a lot of issues. It may not be guaranteed to fix your problem in this case. But it's a good thing to do for any board, and I always start there before doing any deeper troubleshooting, as it does fix a lot of issues.
 
andrewb said:
I gave you an ebay link to exactly what you want in post #11. It's half the price of Digikey.

If that seller won't ship to Canada, just find another on ebay who will.

You don't want to clean the board with isopropyl. If you want to wash the board, go to the Advanced Search page, type in 'Greased Lightning' in the keyword field, and 'andrewb' in the Posted By field,then press Search.

That will find you dozens of posts by me in threads about cleaning boards. Read lots of them.

If you want to clean a board properly, you want to wash it first per above, then remove all socketed chips, clean the inner and outer faces of each leg with a fiberglass pen or a Dremel wire wheel (which is what I use).

Then spray some DeOxit in a small jar, paint some on the chip legs with a small art paintbrush, then reseat the chip a couple of times. Repeat for all socketed chips.

That will remove the 40 years of grime and oxidation that is built up on the chip legs, which causes a lot of issues. It may not be guaranteed to fix your problem in this case. But it's a good thing to do for any board, and I always start there before doing any deeper troubleshooting, as it does fix a lot of issues.
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Oh I must have missed that. Anyway, I'm in Hawaii.

I am sidetracked today and tomorrow so probably no more arcade testing for now.

I was making a delivery at work of a cake and a banana and as I turned around to leave out of the corner of my eye I spotted an Asus ROG Ally. It's a 7" handheld game system that runs Windows 11, 16GB memory, 512GB SSD, and can emulate a lot of systems. I just got home and I'm about to try it out.
 
So I did not test the 10.3V yet. I was Googling what I should set my multimeter to (what symbol) and it said never touch the metal leads with your hands and never touch them together. I thought you touch them together to zero them out? Or is that only with DC?

Anyway, I tested +5V on Centipede PCB.. it reads 5.00.. the -5V reads -5.13.. that okay? I also pressed on all the socketed chips. I have yet to order Deoxit.

When I turn it on, the buttons light up. I mean, they lit up previously. Previously there was a slight noise/hum which is gone. I'm guessing since dialing in the AR-II pot that got rid of the hum?

You know the harness connector.. there's another connector on another part of the board. Any idea what that is used for? Just curious.
 
Since it partially worked before moving it.
And now after moving it you have issues.
Then the likely problem is that something has become loose.
Could be a connector. Could be an IC in a socket. Could be a fuse in a holder.
I would start there. (As always - POWER and CONNECTIONS).

Also put it in TEST and listen for BEEPs.

For Centipede, the AC ripple on +5V and 10.3V is very important to measure if the board is not booting.
Centipedes's Power-On-Reset needs a stable +5VDC. Measuring only DC, with a quality voltmeter, gives only 1/2 the answer.

Centipede's sound amps are powered by +12V and -5V. If sound issues, that's one place to start.

Please study the manual and schematics found here -> both will explain the connectivity and functionality of the game.
Both P20 and P19 need to be attached to the main logic board. The latter provides signals to the monitor (wink, wink) and audio to the ARII/speakers.
(The edge connector near the CPU is used for the CATBOX tester).

 
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