Robotron PS problem

jeff412

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I've got a robotron that quit working tonight. I was getting everything set up for the kids b-day party tomorrow. Played one game on it then went and played a game of pinball. When I came back it was dead. The top led on the power supply is off. All the fuses are good. What should I check?

Jeff
 
I've got a robotron that quit working tonight. I was getting everything set up for the kids b-day party tomorrow. Played one game on it then went and played a game of pinball. When I came back it was dead. The top led on the power supply is off. All the fuses are good. What should I check?

Jeff

Define "dead":

1. monitor dead? (play blind?)
2. boards dead (getting power to monitor?)
3. marquee/coin lights off?

if it is the power supply, it's pretty easy to diagnose with a multimeter. Start with the Transformer out pins (AC), work through the rectifier, filter capacitor, and regulators (DC), and see where the problem is. Use the Robotron Drawing set to see what pins/connections go where.

it doesn't hurt to check the interlock switch, and fuses (all of them), that's the only thing I can think of that will kill the *entire* game at once.

Oh, and it sounds dumb, but check the outlet.
 
I only checked the 5 fuses on the power supply. If there are any others I should check, where are they located? Thanks for the help.

Jeff
 
boards dead. Monitor and marquee on.

Jeff
Define "dead":

1. monitor dead? (play blind?)
2. boards dead (getting power to monitor?)
3. marquee/coin lights off?

if it is the power supply, it's pretty easy to diagnose with a multimeter. Start with the Transformer out pins (AC), work through the rectifier, filter capacitor, and regulators (DC), and see where the problem is. Use the Robotron Drawing set to see what pins/connections go where.

it doesn't hurt to check the interlock switch, and fuses (all of them), that's the only thing I can think of that will kill the *entire* game at once.

Oh, and it sounds dumb, but check the outlet.
 
you have lost the +5vdc, test BR 1 and see if it is good. If BR 1 is good, most likely your LM723 is blown or your 2N6057 IIRC.
 
I've got this one sold. I'm glad I decided to use it for the kid's b-day party. When the guy came by and paid me, he was concerned about the PS. I don't have any of the parts I need to fix it, so I'm just going to order everything and do a complete overhaul. There's nothing worse than selling a game and having someone come back a week later and say it doesn't work anymore. Even though I always say AS-IS, I still end up doing the support after the sale.

Jeff
 
Depending on your point of view, it sounds like the +5V. I rebuild Williams power supplies. PM for details. As Dave said, the bridge rectifier and the voltage regulator are the two most common issues. But I have found the diodes and the resistors are starting to give up the ghost as well as the capacitors. It is probably worth a complete rebuild.

If the guy who bought it wants it rebuilt have him contact me.

ken
 
yellowdog,

Thanks. If I can't get it rebuilt, I'll definately be sending it your way.

Jeff
 
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