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Andrew96_

Maygay EPOCH MPU repair

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Well I have not done a repair thread in a while, but looking on ebay came across this board for 99p plus £3.45 postage, put a first bid on and got it! arrived in the week, I chose this board as it looked fairly clean in the spark protection side and near the ram was good too, it looks like another board with a battery on has affected around the main cpu where some board reworking has taken place, also around the oscillator of the YM sound chip!

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So first steps, remove the previous rework and components in the line of fire of the corrosion

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First area cleaned with a fiber pencil, the area I am going to do first is the 3 via's (through holes) first in the red circle, only one looks really bad but the other 2 have been eaten away a bit so for piece of mind they are going to e reworked too so they don't fail at a later date

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3 very small wires (0.25mm solid wire) put into the 3 holes and one trace above the capacitor (as it looked a little eaten at the edges), soldered and cleaned, then solder resist placed over the top, checked with a meter and continuity of the tracks is good

 

top and bottom of the board pictures

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bit fiddly but that wire is done! it may look like it covers other tracks either side, but that is just the way it looks on the camera! it is not bridged to any other tracks, that's that small area done for tracks

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Edited by Andrew96_
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next, working up the board are these 2 little via's! bottom one looks not to clever round the hole! but they both still make connection! so just in case they do fail later on they are both now done!

 

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looking better!!

 

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Edited by Andrew96_
bad spelllling

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Hi Andrew, how do you get the kaynar wire so perfectly formed to the shape of the original track??  when I’ve tried I get close but they never look as neat as yours!!

Thanks,

Mark.

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solder one end on the track, then just before a bend put a thin nose pliers or tweezers on it, then bend the wire to the track, tack that down with solder and do the same at the next bend, as in this case the bends are not as perfect as I like as the tracks are much smaller than anything else I have worked on and the 0.25mm wire it a tad bigger than the tracks on this board! use plenty of good quality flux but clean it off well or the solder resist won't cover it all properly

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I have been soldering for years and repairing, so it is just take your time and with practice it will come right! key is not to rush, it takes as long as it takes! week after next I take the J-STD-001 soldering test! then we will all be in trouble as that allows me to work on aircraft electronics!! :lol:

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well last bit for tonight!! top 2 tracks done! I know I was working upwards, but it was easier to work on the top track first (runs down the left) then the one under so the soldering iron is not over a finished track when the next track is done! stops the iron inadvertently melting the 2 wires together as there isn't a lot of room on these tracks! they are very close together!

 

just 2 more tracks to go!!

 

 

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Last of the track links in that area done, metered out and all tracks now work! no shorts either!

 

 

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you do realise andy if you fix this board you will be mobbed by a thousand people with broken epoch boards top man 

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Yes you're right. I'm on my last working board. Once it fails, I'll scrap wipeout.

It's a shame.

Edited by booze.net

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1 hour ago, fruit58 said:

you do realise andy if you fix this board you will be mobbed by a thousand people with broken epoch boards top man 

there too time consuming to repair! I am only doing this one as it was in relatively fair condition with rot, there are always more tracks to sort out than you think there is when you first see it! as a business this repair is too much, but as a hobby your not on the clock for time!

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0.6mm rivets added where the electrolytic capacitor goes! where this was messed with before I got the board these were just holes in the board and one capacitor leg was soldered to the topside of the board, thought rivets would give back mechanical strength to hold it back in place.

it's now cooking in the last of the days sun after having solder resist applied to the topside

boy was them rivets fiddly!

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Well I didn't think I would get anything more done on it tonight as a workday! but this evening spent a bit more time on it, components put back in the cpu area! I also desoldered most of the capacitors, someone had changed them but the soldering under was not the best plus as you may be able to see from the very first picture the cap legs are a bit long and not really soldered in very straight! so that was rectified, then in half a hour I managed to sort out the crystal capacitors area near the YM sound chip, pictures below..

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where the track was missing between the resistor and the capacitor I just put a small wire link, I did not feel it was necessary to try and remake the pad and track, its only a epoch board!

Edited by Andrew96_

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Also someone had been round the YM chip you can see in the picture above on 3 sides out of the 4! so this was refluxed up and gone over with a hot stick!

below is the underside of the board and how it looks now

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will hopefully get to test it soon!!! but that's all for tonight! least a bit more progress

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so tonight I put game roms in it, powered it up via a power supply, and after that wait (which seems forever) with a V4 boot rom, the reset light lit ans security light started to flash!!! so least it boots!!

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So put the sound roms in and put it in my wild side,  alarm sounded for a ram clear! yup at least the sound is working! then it booted up fine and worked great, all sounds are there too, so no idea why the sound crystal capacitors were messed with, perhaps previously a sound rom was put in the wrong way and blown it so there then would be no sound whichever way round the rom was! anyway nice to see this board now working for a cost of £4.44 and a labour of love over days!

(perhaps i should put a 'R' in front of epoch and see if someone would buy it for £165 :D )

 

 

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Good to see how you have repaired this one Andrew, nice and intricate and a lot of patience no doubt. 😀👏

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Always interesting Andrew, just wish I was more capable at it! It’s a great skill to have!

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