PCB Repair Logs Ghost'n Goblins Bootleg

Ghost'n Goblins (Bootleg)

Ghost'n Goblins (Bootleg)

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Repairer: GameDude
Forum Thread: Ghost'n Goblins (Bootleg) PCB Repair

Got this one from the same pile of PCB's as RYGAR. Its Ghost n Goblins and in my opinion bootleg or not damn worth spending the time to fix and I did.

To start with it was in a sorry state, bodgy repairs, PCB tracks that were vaporized by the touch of the last solder iron (this is more to do with the cheap PCb used by the bootleg), missing audio parts and half an AMP missing.

Start with the usual power up see whats happening and got a picture that composed of backgrounds only, no sprites and the foreground picture was fading in and out left to right. Sometimes there was just a shadow style edge and sometimes after warm up most of the text was there however only white. Of course no audio as well but I will deal with that later.

Started with the 2114 sprite ram in the middle of the video PCB (11e-12e-11h-12h-11j-12j), two had been poorly replaced but I left them for now and concentrated on the rest, they were all different indicating someone had a problem here before.

I piggybacked the ram and on one I got sprites back but with jailbar effect... a good start! I decided that someone elses crap repair was not worth relying on so I de-soldered all 6 2114's, checked continuity on all pins and wire bridged any damaged tracks as it happened only that previous repair was bad/damaged. I socketed all 6 and replaced with known good ram and got sprites back with no problems.

Ok moving on to the forground text I concentrated on the CPU PCB as its responsible for basic stuff like this, I used a scope to watch what was in the lines and looked for a signal similar to the distorted graphics. I found the signal near the main program ram opposite side to the audio, I traced it back through the circuit until I got to a 74LS157 (10c) third row in right where the audio is pins 1 and 2 were pulsing but pin 3 (output) was stuck high. Swapping had no effect so I went one up the chain from the output to a 74LS174 (4f) roughly in the middle of the PCB and swapped that and BINGO foreground text is back.

OK Problem 3 is the audio, one of the YM2203 (14e) was missing as well as one of the Y3014 op amp (14d) and the AMP itself, replaced all this but no audio - oops amp was in backwards an easy mistake when nothing is labeled on the PCB . OK Audio is OK for FM effects but crap for digital seems wrong, turned out the second Y3014 (13d) that was still on the PCB was totally dead, swapping that gave back all sound YAY!.

Problem 4 was strange, all color was OK except the lives and the weapon box was there but missing a color and was purple instead of white and browns, since this was part of the foreground I figured maybe still a bad chip or trace somewhere here, spent a few hours on the IC's and couldnt find anything wrong, on a hunch I decided to check the color ram 2148 and piggybacked a good ram on each in turn, on the middle 2148 ram (7d) I got a positive result so de-soldered and socketed the position and tried the new ram. New ram worked and I also now got the ram rom test screen on boot, I noticed in MAME it was there but not on the bootleg but put it down to maybe different rom set DOH! Well it works now.

Problem 5 showed up after a little playing I noticed just when you get to the area with the lifts a flash of yellow and sometimes some misplaced graphics showed, the misplaced graphics also affected the on screen interaction so I figured I will check the background ram but it seemed OK. Seeing as it works well up until then I figure maybe a ROM but if its bad it should always happen and it wasnt so I checked voltage on the PCB and had a .2volt drop from 4.85 to 4.65, a little to low so I wire linked GND and 5volt from the edge connector directly to the video PCB and now get a more healthy 4.8volts and no more problems

As it turns out one of the 2114's that was replaced by the last repair was totally dead so 2 of the 6 were bad.

It was a big job and took most of my Sunday but it is worth it for this game I think...

Update on that last problem, seems the V+ was not entirely the problem, it happens less but still there so time to check more IC. I started on the video board left side (background data) and given the problem and its intermittent behaviour decided to piggyback sections of LSxxx chips and see what happens. A positive result! no more background corruption on up/down scrolling, I played to the second level, there is a lift that goes up and down so while there I slowly removed the piggybacked chips till the problem happened.

As it turned out a LS157 @ 9c was the problem, it even compared OK in the comparitor... just flakey old crap I guess... anyway that last prob is now definately FIXED!

I also labeled all IC locations based on an original board which is pretty much the same except the bootleg is more spread out.

Repairer: Arcade King
Forum Thread: [hhttp://www.aussiearcade.com.au/showthread.php/20971-Another-bootleg-GnG Ghost'n Goblins (Bootleg) PCB Repair]

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