Galaga PCB Repair Question

musicman282

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So I purchased a rough original galaga board with the intention to install a renew kit on it and get it working. This board is in rough shape and I have a question for everyone. I noticed that capacitor C1 on the video board is blown apart. Do you think this means that the board was over-voltaged at some point? I've read that it takes hours to complete the renew kit and I don't want to spend all that time if all the components are fried from someone hooking up bad voltage to this board. Anyone have an opinion?
 
Here are the things I would do.
C1 is across the 5 volt side.
-Put a meter (resister mode(ohm)) across where the C1 use to be and check for a dead short. If you read zero. It means the board is shorted out.
-Install a new C1 and test out the board. Plug in the board into a power supply and turn it on remotely. You really don't want to be putting your face into something that might explode.
-Check to see if the board is semi functional by using a logic probe to look for signals around the CPU(4e). If you can see signals I would at that time invest in the time and effrot to fix it.
 
Here are the things I would do.
C1 is across the 5 volt side.
-Put a meter (resister mode(ohm)) across where the C1 use to be and check for a dead short. If you read zero. It means the board is shorted out.
-Install a new C1 and test out the board. Plug in the board into a power supply and turn it on remotely. You really don't want to be putting your face into something that might explode.
-Check to see if the board is semi functional by using a logic probe to look for signals around the CPU(4e). If you can see signals I would at that time invest in the time and effrot to fix it.
Thanks for the advice. This is exactly what I'm going to do. I'd just hate to waste 8 hours and couldn't think of a good way to test for failures.
 
If the capacitor actually blew up it means that the maximum working voltage for the capacitor was exceeded. If that is the case and a too high voltage was applied to the +5V line, there could be a lot of IC problems and some that may not show up immediately as the ICs may have also had their max voltage exceeded and were damaged. If you really like Galaga you may want to consider looking for a second boardset - it's always good to have a backup set. I'd be really leery of putting a lot of work into that video board only to have it continue to be a problem as ICs fail. That renew kit is great for renewing a functional board and "bulletproofing" it. It is no guarantee that it will repair one of unknown condition.

I would try powering up the board if not shorted as suggested. See if it is functioning. If it is dead or you carefully feel that the ICs are really hot, I'd spend all of the renew kit efforts on a different functioning boardset. It is a lot of work to replace all of the sockets and you certainly don't want to do it twice.


Bill
 
This can also happen if the capacitor was internally shorted because of physical damage. Since it blew apart any physical damage such as big dents in the side of it may not be apparent.
 
It could have been one of those famous leaking caps from a few years back. Funny how caps don't last long with out the stabilizing chemicals in them.

As for the feel the heat IC method, You might want to put a Little water on your finger first. Some ceramic ICs and metal can transistors can get really hot. A little water will prevent you from burning a finger.
 
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