I've got a pile of boards from The Lass O Gowrie, and have been going through some of them (ex Paul Swan). Fixing these as a favor for Gareth free when I have the time.... in return for parts off the scrappers and the odd free pint of Bettys Best ale.
A LOT of the boards have had multiple faults, so I'm guessing quite a few have been cut and shut jobs in the past...... This Commando board had faults on the Bottom Board and the Main Board, but as it was mostly working, thought it would be nice to fix it.... Spent a few hours on it today..... Here we go.....
MANUAL PDF from CrazyKong.com , excellent detailed schematics....
Missing sprites....
Was one of the pair of 2114 rams in the corner of the bottom board....
Sound Fault... Hissing and some sounds missing...
Suspect
the FM sound chips, will isolate by lifting r41 and r42 to find which
1/2 of the section is faulty.. with a bit of luck it might just be one
of the 8 pin YM3014's and not the 40 Pin YM-2203 - Will also check 7C
(74139) and 9E just to save time...
Result.... It was one of the YM3014's..... (However I did swap out the 40 pin YM-2203 though)
Both Coin Inputs ON....
Suspect 6B - 74LS367 - DB7 and DB6 are the inputs, but also share these with a couple of other ic's....
Result... Yep... it was the 367 at 6B.... however the ABI boardmaster seemed happy with it ???
I
cut pins 3 and 9, and it no longer coined up to 2 credits when powered
up (as the Data Bus is pulled up via RA10!! , So replaced it....
ALL FIXED NOW....
ColinD2013-09-13 00:31:13
A LOT of the boards have had multiple faults, so I'm guessing quite a few have been cut and shut jobs in the past...... This Commando board had faults on the Bottom Board and the Main Board, but as it was mostly working, thought it would be nice to fix it.... Spent a few hours on it today..... Here we go.....
MANUAL PDF from CrazyKong.com , excellent detailed schematics....
Missing sprites....
Was one of the pair of 2114 rams in the corner of the bottom board....
Sound Fault... Hissing and some sounds missing...
Suspect
the FM sound chips, will isolate by lifting r41 and r42 to find which
1/2 of the section is faulty.. with a bit of luck it might just be one
of the 8 pin YM3014's and not the 40 Pin YM-2203 - Will also check 7C
(74139) and 9E just to save time...
Result.... It was one of the YM3014's.....
(However I did swap out the 40 pin YM-2203 though)Both Coin Inputs ON....
Suspect 6B - 74LS367 - DB7 and DB6 are the inputs, but also share these with a couple of other ic's....
Result... Yep... it was the 367 at 6B.... however the ABI boardmaster seemed happy with it ???
I
cut pins 3 and 9, and it no longer coined up to 2 credits when powered
up (as the Data Bus is pulled up via RA10!! , So replaced it....
ALL FIXED NOW....
ColinD2013-09-13 00:31:13