SEGA Mega Play restoration

Not about HAMradio this time. I really wish to spend all my available free time to build HAMradio stuff but real live is of course not like that. We have other things to do as well, not less interesting though.

 This SEGA Mega Play arcade system was brought by a friend and ex colleague almost 10 years ago. If I could take a look at it if time allows, no pressure. So, there it still stands in my garage after a decade I think it is time to have a look at it.

This system is from 1993. No SMD parts, lots of microswitches, high voltage TV screens that kind of stuff. All locks are broken like someone was desperate to find money. Yes, this old gear plays on vintage dutch guilders. And while inspecting and trying to clean some parts I found, as a surprise, 2 dutch guilders...

However my big concern is connecting power to this object since it hasn't been powered for over a decade. And I really don't know when it has been powered before I got it here. So I have to take extreme care before I switch this machine on.

Made some interior photos to show.

This is the motherboard. It seems it is used in more types of SEGA arcade machines. First thing I noticed was a very rusty CR2032 battery. Of course I broke the plastic fitting bracket when I tried to remove it, but that is repairable. Tried to remove the dust from the components with a brush but it seems to be pretty sticky. Compressed air didn't do the trick either. Any hints on how to clean this printboard? I already checked for faulty caps but so far they all look pretty decent.

By the way, looking for information on these motherboards I saw them sold with just one game in pristine condition for at least $2500 on eBay. Wow!

All switches are the same micro format, even in the joysticks. Luckely these are easy to get if some will malfunction. I noticed on that was partly broken but could fix it with a ty-rap.

Push buttons could only be pushed once, they just were that sticky. This kind of arcade machines could be found in lunchrooms and cafetarias/grillrooms. No wonder they are sticky. After cleaning them all is ok now.

Reading some tips & hints about restoring old electronic transistorized equipment I found some usable tips for my project.

First of all I should connect the power supply through a variac (variable mains transformer). I find a reasonable prized one on the internet. 

This system contains a main transformer which I think feeds some auxillairy equipment like lights etc. and a multivoltage powersupply unit that probabely powers the motherboard. More photos from that in another post.

My biggest concern is not the transformer and the multivoltage unit but the 2 high voltage TV screens. I inspected and tried to clean the electronics behind the smallest screen tube. But so far didn't find a way to access the big screen electronics yet.

My idea is to continue cleaning the motherboard. Disconnect all connections from the powersupply. Disconnect the screens from the mains feed by pulling the fuses. Adding mains voltage slowly to the powersupply and measure all outputs first when reaching 230V in. Then connect the TV screens one by one adding again voltage slowly with the variac till 230V. If those are working I'll connect the motherboard.

Since I have no experience restoring this kind old equipment all tips are welcome. Please let me know in the comments below. I especially would like to know how to safely clean the motherboard without damaging the components. I guess placing the thing in the dishwasher is not a good idea ;-).