Qbert Power Supply

BubbaK

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I finally got a chance to look at a Qbert my buddy is selling. The power supply board is shot as I see some burnt resistors and other burn marks and the only thing powering up is the marquee lights. The lower voltage led was lit on the board, but the 30v light was not. I hope it didn't take out the sound board as well. A quick search through the forum last night showed problems with these power supply boards, so i am going to change it out for a switcher from AS. I'm also going to get a cap kit for the sound and CPU board and the battery mod kit. I noticed on the back door when I opened it that there was a switcher installed already, but it was only stamped 5v I think. Is that a stock setup or has someone already been in this machine? I should have taken a few pictures so I could have a better reference rather than relying on my memory.

I only had a few minutes last night to look at it. I plan on spending a few more minutes tonight looking through it to see what else may catch my eye. Anything else I should look into with this during a first scan?
 
Keep in mind that if you go with a switcher the knocker will be weak, if it works at all.
If your not worried about the knocker the switcher works fine.
I sell rebuilt power supplys and also have rebuild kits if you end up wanting to rebuild your original.
 
Keep in mind that if you go with a switcher the knocker will be weak, if it works at all.

I wonder why. Does your average switcher just not deliver enough current, or responds strangely to the load? Would a bigger swicher (say, a 650W meant for ATX computers) make a difference? I wonder if you could work around it using a separate VR-based power supply to the knocker.
 
Thanks for the info Riptor.. I will keep that in mind if I end up buying the machine. After seeing my buddys 4year old daughters face light up when I started looking at it last night, I don't know if I can pry the game away from him/her just yet.
 
I wonder why. Does your average switcher just not deliver enough current, or responds strangely to the load? Would a bigger swicher (say, a 650W meant for ATX computers) make a difference? I wonder if you could work around it using a separate VR-based power supply to the knocker.


The knocker runs at 30vdc. The switcher only outputs 12vdc to the knocker and sound board.
 
Wrong, the AS switcher puts out 24v for the knocker. Its just not enough to kick the knocker. I suppose you could change the coil to make it work better but who knows.
 
The knocker works fine with the AS kit. It's just half as loud is all.


It works on some, not on all of them. I did a bunch of testing with 24v switchers before arcade shop came out with theirs. Some knockers had issues working at all with the 24v so I scrapped the whole project.
 
It works on some, not on all of them. I did a bunch of testing with 24v switchers before arcade shop came out with theirs. Some knockers had issues working at all with the 24v so I scrapped the whole project.

Yeah, I guess I've only tested it in my machine. I have had enough other issues with mine to just be happy that it is now working with the switcher. I also finally replaced the chip at U16. That cured the remainder of the sound issues I was having.
 
Wrong, the AS switcher puts out 24v for the knocker. Its just not enough to kick the knocker. I suppose you could change the coil to make it work better but who knows.


From Arcadeshops website.... apparently its something new as of 5/2010

* Eliminates the +30v power, which is known to burn up the Sound AMP I.C.
* Prevents burning up the Knocker and Interconnect PCB due to short circuit
* +12v is now used for Sound (and the Knocker in Q*bert)
* Game cabinet temperature will be cooler, increasing component longevity
* Heavy duty Power Supply with 4 AMPs on the +12v rail
 
I got my switcher kit for Qbert and am going to go and install it today. I still haven't seen any comments about the 5v switcher that is currently installed in this machine. Is this from the factory or is it something that I will be removing? I am trying to plan my tool bag for what I need to bring and not sure if its something I have to eliminate...

Can someone shoot a picture of their back door with the switcher installed?
 
The 5v switcher you currently have is not original and will be removed when you install the AS switcher.

THanks.. I left it in there for the time being as they cut the wires off the plug and ran to the new switcher. I found out today that the game was purchased a few years ago from TNT. I must say I'm a bit surprised at some of the work I see in this machine coming from them. The guy I'm getting it from definitely didn't tinker with it.
 
The knocker runs at 30vdc. The switcher only outputs 12vdc to the knocker and sound board.

Aha!

I would probably build a 30V regulator-based power supply (using e.g. this) and actuate the knocker with a relay. Sure, it means cutting up more wires, but everything works then, and you've isolated the apparently vulnerable sound IC from the voltages that tend to kill it (if the above is to go by).
 
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Its not the 30v that kills the sound amp. Its the much higher voltage that gets pumped through it when the 30v zener on the power supply fails. Its a poor design to say the least.
Guys, im pretty sure the arcadeshop switcher uses 24v for the sound and knocker. The amp will run on lower voltage but the knocker is marginal even at 24v. You can buy 30v switchers but they are pretty expensive.
 
Might be easier to find a coil for the knocker that works well on 24VDC...

Looks like my Black hole has a knocker that run on 24V... it's an A-5195. What coil does Q*Bert use?
 
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