HELP! We put in a new power supply in Q*Bert won't start

morbidboy

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HELP! We put in a new power supply in Q*Bert won't start

I attached the new Arcade Shop power supply to Q*Bert and had gorfchampion and alejandromad double check my work. They ok'd it and we turned it on. The game won't start and the screen is just gibberish.

Here:s a pic of the hooked up power supply:
qpowersupply.jpg


And a pic of the frozen screen:
qbertblahscreen.jpg


alejandromad checked the voltage and the power supply is working but we can't get the game to start. Does anyone know how to fix it our get the game to start?

HELP!!!!!
 
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What is the voltage with load?

Just make sure you measure it under load. Very important for Qbert. I had to set mine at 5.2 and has worked perfect since install last year.
 
does the garbage move around at all?

It is trying to do initial testing before going to "boot" mode.

EDIT:

Clean and re seat edge connectors and maybe wiggle without power then power up.
 
The voltage was checked, under load,and adjusted between 4.99 and 5.12 or so. The game was power cycled a couple of times during these adjustments and no change was observed.

The screen is static - no moving around at all - it doesn't change.

Interestingly enough, the first time we turned it on the game looked like it started but the attract screen was frozen and it wouldn't take credits. A power cycle later it was just blocks of garbage video.
 
Well, this could be a coincidence, however, it looks like the processor isn't being recognized. Do you have another to swap?

We all try to look for the simplest solution. This just may be one of those times when something craps out...
 
I assume by the tone of this thread that everything was 100% working with the original power supply and now it's not with the new one?


I'd be measuring voltages at the legs of the ram chips to see what's getting to them. (maybe you are referring to those points?)
 
Q*Bert was working fine until the Power Supply Assembly went bad. Then We replaced it and now the screen shows that image.

I assume by the tone of this thread that everything was 100% working with the original power supply and now it's not with the new one?


I'd be measuring voltages at the legs of the ram chips to see what's getting to them. (maybe you are referring to those points?)
 
You said the original ps went bad? Well that could have taken out a few things.. Your sound board might have been fried with the CPU.. Is the filter/interconnect pcb clean? Any burnt header pins or connectors?

Good luck, qberts can be a bitch.
 
You said the original ps went bad? Well that could have taken out a few things.. Your sound board might have been fried with the CPU.. Is the filter/interconnect pcb clean? Any burnt header pins or connectors?

Good luck, qberts can be a bitch.

+1

I would look at cpu first! they are more fragile than most other chips on the board and usually in the top 3 of chips likely to fail with a failed power supply. Ram chips and sound amps are in the running though.
 
Yeah, when the power supply gives up, there can be a spike of voltage that will kill other discrete components.

Really the most intelligent thing to do there would be to drop in a known working board and see if it boots. That will confirm that you have a board level problem. No use speculating until you know where the issue lies - power supply or board.

Once you've confirmed it's a board level issue, start with CPU.
 
I guess I'll try a new board. Quartersarcade.com has one for $50.

Yeah, when the power supply gives up, there can be a spike of voltage that will kill other discrete components.

Really the most intelligent thing to do there would be to drop in a known working board and see if it boots. That will confirm that you have a board level problem. No use speculating until you know where the issue lies - power supply or board.

Once you've confirmed it's a board level issue, start with CPU.
 
alejandromad let me borrow a board over the weekend, to switch out with my board to see if I get a different reaction letting me know if I need to buy a new board.

So having some free time this morning, I went to turn Q*Bert. No power. I pulled and checked all of the fuses; no problems. While I was doing this, Annie (wife and Co-owner) wheeled up to me to find out why I was cursing like Yosemite Sam. I went to check the fuses again and She said, "Fuck, let's just throw it out. It's been nothing but trouble...."

We'll I guess it heard her because when I turn it on, Q*Bert started up and was ready for business.
 
Sorry for getting to this thread so late, but this is common-ish with Qberts I'm finding out. The reason you were getting gibberish on the screen is that the PCB in Qbert needs 5v and 12V (11.53vdc). When you only supply 5v to the board (i.e. use an arcadeshop power supply) the 5v will get to the board, but the arcadeshop power supply doesn't supply 12v to the board, it relies on the original circuit to do this. Coincidentally, the original qbert supply uses this 12v supply to create the 5v regulated supply to the motherboard, so when the 12v disappears it looks like your power board is shot (and it might be fine!).

When this 12vdc feed goes out, it's often a bad fuse or connection at the power block in the bottom of the cabinet. Worst case scenario, one of the bridge rectifiers might go. In your case, it sounds like a fuse (just like it was on my cabinet) and I'd recommend cleaning the fuse for good contact and install new fuses as well.

Here's the post I made about this a month ago with a little more detail:
http://forums.arcade-museum.com/show...ge=3&p=1965009

-BAZ-
tbazzano
 
Sorry for getting to this thread so late, but this is common-ish with Qberts I'm finding out. The reason you were getting gibberish on the screen is that the PCB in Qbert needs 5v and 12V (11.53vdc). When you only supply 5v to the board (i.e. use an arcadeshop power supply) the 5v will get to the board, but the arcadeshop power supply doesn't supply 12v to the board, it relies on the original circuit to do this. Coincidentally, the original qbert supply uses this 12v supply to create the 5v regulated supply to the motherboard, so when the 12v disappears it looks like your power board is shot (and it might be fine!).

When this 12vdc feed goes out, it's often a bad fuse or connection at the power block in the bottom of the cabinet. Worst case scenario, one of the bridge rectifiers might go. In your case, it sounds like a fuse (just like it was on my cabinet) and I'd recommend cleaning the fuse for good contact and install new fuses as well.

Here's the post I made about this a month ago with a little more detail:
http://forums.arcade-museum.com/show...ge=3&p=1965009

-BAZ-
tbazzano

WOW, fantastic info! Someone should make sure this gets saved for future info. Great stuff.

Your link doesn't work. What's the thread?
 
When you only supply 5v to the board (i.e. use an arcadeshop power supply) the 5v will get to the board, but the arcadeshop power supply doesn't supply 12v to the board, it relies on the original circuit to do this. Coincidentally, the original qbert supply uses this 12v supply to create the 5v regulated supply to the motherboard, so when the 12v disappears it looks like your power board is shot (and it might be fine!).

To elaborate a bit more...

There is an 11.5 VDC output (from a bridge rectifier on the transformer brick) that is supplied to the original MA-303 Power Supply Assembly and is used to create 5 VDC for game logic.
This is replaced (in the AS supply) by the switcher 5V output.

The game logic PCB also receives this 11.5VDC directly from the transformer brick (as shown in the attached image) - completely bypassing the MA-303 Power Supply Assembly (where the 5VDC for game logic is created).

An issue here would not be alleviated by replacing the original MA-303 with the AS option.

I am guessing, since I have worked on this game in person, that the connectors are tired and worn (they are, in fact, burned) and in disconnecting and reconnecting you somehow got them to make sufficient contact.

Sage, we should rebuild those connectors and follow Baz' advice regarding the fuse holders too.
 

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