New Life Games LLC
General NLG Chat => General Chat, Slot Shop **Tech Talk** Welcome wagon and other stuff. (Off-Topic Post Welcome) => Topic started by: Amechanic on September 08, 2018, 06:36:35 PM
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I felt this would be a good example to show people why you need to use new thermal paste and the correct heat sink on parts like this bridge rectifier. This is a Power Supply is from a Bally E-Series. It had just the small U shaped heat sink on the rectifier and no thermal paste. There should have been a larger U Shaped heat sink on the rectifier first, then the smaller one that’s sitting on the header pins. I got this PS from a friend today who found this in a game he had. Hopefully I can bebuild it. One diode looks to have gotten a little hot too.
Here is a pic of a PS with both heat sinks installed with thermal paste.
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To add to your post, all modern CPU's will throttle when their thermal design power is reached. It is done to save the cpu from burning up. So it slows down a lot to until it cools down enough to resume normal operation. The job of the thermal paste is to transfer the heat generated by the cpu to the heat sink where it dissipates. Without paste, the transfer of heat is compromised because there are micro gaps between the surface of the cpu and the surface of the heatsink. The thermal paste's job is to fill in these gaps, thus allowing proper heat transfer. Over time, this paste becomes brittle and dry, and the heat transfer is no longer as efficient, causing the cpu to potentially overheat and throttle. So if you have a game that kind of "stutters" this might be the reason why. As a general part of my machine's clean up and preparation, I always remove the heatsink from the cpu and clean out the old paste so that both surfaces are shinny and devoid of any of the old paste and the put a nice layer of new paste and re-assemble.
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Thanks for your post. I felt it was important for this to be posted for others to see. I just finished rebuilding about 6 or so of these old Bally PS Boards and made sure that the bridge rectifiers heat sinks as well as the 5V rectifiers all were cleaned and had new thermal past applied. It not worth skipping effort of not using new paste if your taking the time to fix the problem.