Looking for repair shop in Houston Texas

houseofpower

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Donor 2011
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Need help with a Stargate & Robotron to get up and running. Anyone know of someone that can work on these? Near te 290 & Hollister area. thx
 
Any hints on what kind of issues you are having? The more specific you are they better the responses will be.

I am not a repair shop, but I do work on Williams boards.

ken
 
Just to give you a review of Yellowdog, He fixed my Stargate right up!!! Good prices and turn around as well!!! Highly recommended.
 
Robotron & Stargate issues

Ken,

I really don't know. It may be a power supply, or board issue. To be honest I don't know much about this stuff. These are my first games to rebuild from the ground up. Cabinets are done but can't get it to work. One board I got from a guy that he said was tested and works. I would be glad to pay you to help me get these things going.

thanks
 
Some basic questions:
1) Are you using an original Williams power supply or a switching power supply?
--- Williams PS boards typically attach to the big transformer in the bottom of the cabinet. Older PS boards have two big heat sinks on the board (Defender style). Newer PS boards have a separate heat sink (Joust style)
--- Switching power supplies typically attach directly to the 120VAC wall power and look like vented steel bricks.

If you have a Williams power supply, there are 3 LEDs on it that indicate +5V, +12V and -5V are approximately correct. If those are not lit, then the power supply probably needs to be rebuilt.

Always start with the power. If the power is not right, then nothing is going to run right.

2) When testing, make sure the fuses are good and the back door interlock switch is pulled out. There is a 3A slow blow fuse on the power brick next to the big transformer. This is the main power fuse. If it is out, you are not powered up.

The back door interlock switch on Williams machines is the white switch in the upper right corner as you face the back. This is an interlock switch just like your refrigerator uses. When the door is closed, it is pressed in and power will go to the components. The difference from a refrigerator switch is that it can pull out and that turns the switch on in a "cheater" mode so you can work on the internals of the machine. You wouldn't believe the number of "I took the back off and it wouldn't play anymore" stories there are floating around.

3) Once you have verified that you have the correct power to the boards, normally there are some diagnostic messages that flash on the 7 segment LED on the ROM card. These messages are typically in the form of three numbers that flash. The first number is whether it is a RAM or ROM error. The second two numbers tell the positions of the bad chip. For RAM chips (first number 1) it is the bank and chip numbers. For ROM chips (first number 2) it is the ROM chip number.

If you don't see any numbers flashing is when the fun begins.

ken
 
Board Issues

We are using the factory Williams power supply. We have tried to power up the game with 3 different PS boards. 2 of the boards lit up the 3 LEDs and the game started to boot but the 7 segment LED displayed 2 different RAM errors. We replaced the RAM chips and the error stayed the same with both PS boards. After doing some research we found one of the instances that causes the RAM errors is a faulty PS board. 3 boards have been tried. 2 cause 2 different RAM errors and the third PS board has one of the 3 LEDs not lighting.
 
The three LEDs on the power supply are an indication that the voltages are approximately correct. The real way to tell is to use a voltmeter at the PS board, at the MPU board and then finally at the 4 corners of the RAM chips.

By doing it in this order you will eliminate the PS board, the power cables and finally the connectors on the MPU board as the cause. Sometimes you will see the correct voltages at the PS board and there will be a bad connector or a broken wire in the wiring harness and the coltages won't be correct at the MPU board. Sometimes they are correct at the input of the MPU board and wrong at the RAM chips indicating that something is not correct on the MPU board.

And then, sometimes the voltages are right and it is something wrong at the chip level.

ken
 
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