Leaderboard

A 12K CPU wouldn't boot and it was sufffering from the usual battery vapours to the CPU. Most the tinning was flaking off of the legs which can cause short circuits across the CPU pins. It also falls down into the chips underneath and shorts them out too! The CPU was pretty lose in it's socket so the old green one had to come off. The CPU itself needed all the legs cleaning to get rid off what was left of the tinning on the pins and to get the black stuff underneath off. One of the pins fell off as it was corroded through so I put the CPU aside to test it later, not expecting it to work of course. Next was the RAM which was more or less welded into it's green sockets with corrosion. With a lot of careful persuasion they came out eventually and these were also put aside thinking they were probably knackered. In with another two new sockets, new CPU and test RAM and power up. Nothing... not surprising really I suppose. A quick check on the DATA bus shows the buffer chip to be OK but not so the ADDRESS line chips, only a couple of pins are actually passing any signal through. In with two new 74LS244's and power up and Bingo she lives. So, it's back to the original RAM and blow me that works too. Solder a new leg on the CPU, plug it in and ..... nothing! Well you can't have everything. Next was an I/O board which wouldn't boot. Checking around showed that it was stuck in RESET. With the board on the bench I found there was about 70 Ohms to ground on the RESET line. This goes to two transistors and 7 chips. Removing the transistors showed they were blameless so the next thing was to unsolder every pin 15 of the 7 chips to see which one was dragging it down. That turned out to be IC14 (74LS259). With a new one fitted it burst into life.

Ah cool, thanks for the info. I'd love to get Breakthru And Blockbuster emulated, BlockBuster was a good money earner in the day!

I was right 🤣

Just got back,gave front a very quick clean.Cabinet good,glass good.Appears to be no battery damage at all.It was a blue battery but i have removed it.Will now clean board with ipa and leave to dry.So condition really is very good.The mpu has 1988 date on.

ok so remove the small brown and blue link wires marked with a red X move the 2 wires (brown and red) on the pink spot to the terminal marked 120 shown by the pink arrow then link the 2 pins shown with the white wire (If you just cut the blue wire at the other end you then already have is soldered to 0v) job done! 240v operation

yeah that is easy to change, will do a diag of what you need to do

That's a Coinmaster, probably their EVF board with a 6809 CPU.

look at all the little chips and transister on the boards to see if there is any burn marks or holes on them starting with them on the display

Don’t know which lamp board you have as cannot see it, but if its the one made by one stop ( mk2 version) your most likely need a working one as they are very very prone to the custom chip blowing and alpha not working

Probably requires a new mpu and/or a lampboard which the alpha is connected to. Alpha is one of the first things to suffer from board damage on Epoch.

Oh my god,epoch.scrap it,or there are some boards on ebay fot about 80 quid.Epoch is diabolical.