Q*bert Video Issues

MoJoS

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Donor 2011
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All, I have an issue with a video problem on a Q*bert game. When purchased this game worked fine with an occasional video glitch (scrambled video) when turned on. Turning the game off and back on would solve the problem. Now however, that no longer works. When I turn on the game I get the "Hello, I'm turned on" audio and then a "scrambled" screen as depicted in the attached image. I've checked all of the voltages and they are where they should be so any help will be greatly appreciated.
 

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Interconnect or power supply

I'd start by looking at each connector on the interconnect pcb.. Long skinny one that everything plugs into.. I'd bet the last 2 connectors on the right are burnt.. Actually look at the back of the pcb too..

Or, your power supply is weak.
 
Thanks for the reply. If by interconnect pcb, you mean the filter board, this unit doesn't have one. It appears that it was taken out at some time previous to my purchasing the game. For the power supply I've checked all of the voltages and they are where they should be. I've also checked the voltages at the main pcb and they are all at slightly above the recommended voltages (5.1V as opposed to 5V, etc). Same for the voltages at the sound board.
 
Filter or interconnect

Call it whichever, but it's gone? Humm.. I knew you could do that, but I've never seen one do it. So are all the connectors gone? Just the main pcb connects?

I was having the exact same issue as you, but it was 2 burnt connectors which power the 5volts.. Replaced them and the header pins and it's all good.. I also recapped the audio pcb, and main pcb.. Plus added a NVRAM so it would actually save high scores.. Might want to try reseating some of the roms, and other chips..

Remember, loose or old header pins and connectors are not your friend.. They are usually the reason games have issues..

Please post some pictures of how your pcbs are set up without the filter pcb.
 
I have removed the filter board on several machines. You just do away with the connectors and solder the wires and heatshrink them. Also, early build machines did not have them at all.
Are you turning the machine on with the power switch on the machine or are you turning on more than one game via a power strip or something similar?
 
Let me catch up here.

Ripitor is correct in that the wires that went to the filter board have been connected directly to the harness and heat shrunk. Initially I looked at and repaired some of the header pins as some were in bad shape.

This game is plugged directly into the outlet and is turned on with the power switch.
 
There are several reasons that your board could be doing this.

First of all, have you done the reset cap upgrade? The larger cap value extends the power on reset time and may help.

If you have and the problem still exists, then the best thing would be to have one of the repair guys here take a look at the board for you. This problem could be caused a dozen things and can only be diagnosed on someone's workbench. Otherwise we are all speculating.

Bill
 
I assume that you are talking about changing out C25 on the mlb and if so then yes. Who are the repair guys here so I can get in touch with them? Thanks!!
 
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