Repair Log thread

[system11]

Well, someone asked me about the Kaneko Super-Nova sound fix, and while the information is public it's not widely publicised. Rather than just detail that one fix, perhaps people could post links to their PCB repair logs in here, if they have one.

Here's mine - there's nothing too spectacular in there, but....

http://www.system11.org/temp/PCB_repairs.html

Apologies if incorrect terms are used, I was very much in the early phases of learning when most of this was done.

[D]

These are logs/forums not by myself, but by others.
If I missed the point of this sticky please remove this reply and sorry for the trouble.
http://www.solvalou.com/messages.php
http://forums.webmagic.com/ubbthreads/p ... d=KLOVHELP
http://www.jammaplus.co.uk/ (needs registry)

[rtw]

Fixing the sound in Ninja Kid II

http://home.online.no/~tjaberg/ninja_kid_2/

rtw

[channelmaniac]

Hi everyone!

All my repair logs have moved to here: http://newlifegames.com/nlg/index.php?board=25.0

They are sorted by manufacturer and I hope they help you keep your systems running!

Enjoy

RJ

[ZOM]

Oh my... great stuff channelmaniac!
That page got instantly bookmarked.

[neorichieb1971]

Do we have a UK PCB repair guy who is reliable?

[IronGiant]

Do we have a UK PCB repair guy who is reliable?

Without wishing to blow my own trumpet, I'd say that i'm reliable. I'm sure others here (and on Arcade Otaku where I post under the ID of Vectorglow) would vouch for me.

I hope!

Other repairers are, of course, available. Channelmaniac in the US is very good, as is Tim Matthews and P-Man.

[system11]

Tim doesn't repair them for money though.

Also - I updated my repair log, the online version was quite out of date.

[opt2not]

Just going to pop my Raiden DX board fix in here. Brought this baby back from the dead!:
http://shmups.system11.org/viewtopic.php?f=6&t=40532

[Elgen]

I do some repairs and other stuff and post it on my blog...enjoy
http://elgensrepairs.blogspot.dk/

[Artemio]

Although still learning and doing basic ones, I decided to document the ones I've done so far. They are in Spanish though, since there are so few resources in that language. However, if anyone ever wants some translation of anything, I'll do that gladly.

http://foro.arcades.mx/viewforum.php?f=20

[system11]

I've updated my log again - starting to tag the hardware type (where known) in a column to help people searching for repairs to other games on that family.

[Elgen]

Hi, I've done plenty of rep logs since I posted a link to my blog many months ago.
One or two people from here have asked me if I would post in this thread every time I make a new rep log. I'll be happy to do so, but is that a general wish, or is it just a few ones?
Don't want to be known as 'The Flooder' };-P

[system11]

I just mention it from time to time. Since I last posted there were loads of new entries.

[Elgen]

Okay.
I've have made a lot of new entries on my repairs blog since I last posted a link (20121010). This includes some nice shmups, retrofitting an USB-port on my Fluke9010A, and also some Amiga-stuff (as I went a little Amiga-crazy for a short period };-P).
Please feel free to have look around, and also leave comments; love when people do };-P
http://elgensrepairs.blogspot.dk/

PS: Love the stuff you're doing, Artemio...pitty it's in Spanish...however Google Translate is my good friend there };-P

[Artemio]

Thanks! I am honored since your I have been an avid reader and fan of your blog for quite a while via google reader.

I've been slowed down by an R-Type... Didn't boot every other time, no audio, corrupted backgrounds, corrupted sprites, problems in the scroll, and the last issue I am tracking is vertical red bars in some layers... I don't know if I'll be able to recall everything, so far I've replaced 14 damaged TTLs.

I'd love to get a Fluke, a shame it would be way too expensive to import to Mexico.

Keep up the excellent work, I read all your posts and relive them =)

[Elgen]

Thnx for the kind words. And you too, plz keep up the great work };-P

When I get stuck with/sick of a board, I often put on the shelf and do some other repairs.
Then you can pick it up again after some time, fresh in mind
...I very rarely work on only one project at the time };-P

[Artemio]

Yes, it is hard having only one stubborn board on the bench. However with this one i had so many "this must be it" moments that have been partial fixes, it has grabbed me and is exhausting at the same time. I do have two other boards that I am "working on" at teh moment, but I really haven't since I feel i am so close to finish this one (and I want to play it).

I should leave it fro a while.. it has slowed me down indeed.

[Elgen]

Damn, know the feeling. I have an original R-Type myself, that I've had under the knife at least 3 times without being able to fix it };-S

[system11]

Those can be hard to diagnose, much easier of course if you have a spare M72 set to swap boards around with. I've had problems with several M72 lately, and all but one actually came down to bad connection on the ribbon cables, or bad contact on the top board jumpers.

[Artemio]

Yes, I've been reading your logs too.. there is not much information regarding the M-72. Thanks a lot.

I do have a Gallop at hand, without it it would have been a real nightmare. All there boards on this R-Type had issues:

1) Rom board had faulty 74ls245 and RAM
2) Main board had faulty 74ls74, 74ls245, 74ls244 and a few others...
3) Bottom board had faulty 74ls283 and 74ls273, and some more I haven't found.

With the Gallop boards I fixed one at a time. They are indeed hard to diagnose due to them being stacked. In some cases I could determine the faulty TTL by proper diagnosis, like the faulty flip flop in the audio or the adder in the scroll.. but since the bus has data and address lines in this CPU, it was quite difficult to figure out the 245 and 244s, my lack of experience didn't help there and I had gotten used to diagnosing 68K ans Z80s...

[DrTrouserPlank]

Realistically speaking, other than looking for broken tracks and caps that are doing some sort of one-legged dance, it there any way to repair a duff board without..

1) Tons of really specialist equipment
2) Instruction from someone first hand who has repaired hundreds of boards before and knows the common solution to certain problems?

I've got two boards that are screwed. A bootleg Robocop that just black-screens upon power-up and a Wrestlefest bootleg that to my best recollection (since I haven't powered it on for well over ten years) displays a video signal that looks like the game, but I think it's scrolling rapidly in the horizontal direction. The wrestlefest has a capacitor that is missing a leg so that's an obvious repair.. but would that really cause rolling video signals? The robocop.... christ knows.

I bought these yonks ago off ebay whilst I was constructing a supergun.. in the end it turned out that 2 of the three boards I bought were defective (the two bootlegs) Don't really care as it's a long time ago but it would be nice to have them working as intended.

[system11]

You can't fix anything without at least a logic probe and the willingness to learn basic logic electronics. Then you need someone willing to give a lot of advice and/or refer to the more detailed repair logs out there.

For bootlegs, it's not worth paying someone to fix them.

[DrTrouserPlank]

You can't fix anything without at least a logic probe and the willingness to learn basic logic electronics. Then you need someone willing to give a lot of advice and/or refer to the more detailed repair logs out there.

For bootlegs, it's not worth paying someone to fix them.

My electronics knowledge wasn't too bad back when I actually had an education, but it was more theoretical than practical. Indeed the qualification that I studied for during my teens was discontinued mid-course for a softer, more rounded approach focusing less on "electronics" as such and more on electrical products. The course I studied for prior to that would probably have been A-level electronics grade stuff at the very least by today's standards.

... but in terms of trying to diagnose which IC on a board populated with IC's is causing the problem, well, that's an impossible task given my tools/knowledge. If we are talking about reading pin-by-pin outputs from IC's on a board and trying to establish whether they are high or low, and whether they ought to be high or low given the current state; then that's way beyond my current level of knowledge/expertise.

These boards were about £30-40 a go, and at the time that was an OK price to pay, although not a good price to pay for what effectively turned out to be junk.. What sucks is that they were sold as working, and obviously weren't. More fool me, but I was constructing my first supergun and placed too much trust in sellers with good "reputation".

The fact that you seem to be able to repair so many boards is incredibly impressive; especially those with multiple problems.

Thanks for your reply nonetheless.

[system11]

Did you do the obvios basics? check for underside track damage or IC pins which are bent and bridging? Did you measure the 5v?

[DrTrouserPlank]

Did you do the obvios basics? check for underside track damage or IC pins which are bent and bridging? Did you measure the 5v?

I need to get a magnifying glass. Didn't see any IC's bridging via naked eye but.. Haven't measured the 5V... what would variance in the draw tell me? Only have a multimeter with continuity test abilities.

The Wrestlefest has the disconnected capacitor. There is also an area on the back of the PCB where the screening has been cut and there is Copper visible... but I don't really believe that it's bleeding into other signals by the looks of it. I ought to check for continuity at the very least.. I haven't... As I say, these boards have been sitting in my cupboard rotting and I always asumed that a broken board was effectively junk. My interest in trying to fix these was only ignited by the thread in off-topic about new PCB purchases.

The robocop is a two-board affair. There is a resistor soldered to the same leg as a capacitor that I don't particularly like the look of (It seems odd that anyone would do that) maybe that's my inexperience.... as for the rest of it.. I don't know. I ought to pull the ribbon cables, have a look at the backs (which look fairly clean) and hope for the best.

As I say, I reckon the wrestlefest actually works but with a minor component fault. The robocop, I reckon I got conned.

[undamned]

Had a CPS2 A Board (mother) stop producing video. Audio worked fine and, so far as I could tell from the audio, the controls were also working fine. Scoped out the color out signals and they were fine. Composite sync out, however was dead in the water. Traced it back through a few passive components to H8, which is an 74HC04 inverter. Checked the input to that channel and found it did have signal coming in. Replaced that sucka and now video works great!
-ud

[Crafty+Mech]

I have a few repairs over the last couple months that I figured I would add here to help out others who may run into the same problems.

1943 - Sprite backgrounds opaque instead of transparent (all sprites surrounded by colored box). Burn mark visible underneath 86S100 custom chip (palette mixer) near sprite roms. Bridged pins 5&6 on the suspect 86S100 custom chip, graphics back to normal.

1943 - Missing MCU, board boots but resets immediately. Sourced replacement MCU thanks to Channelmanic over on KLOV. Works like a charm!

Final Fight - Screen was full of a single character patterned over the game graphics. Found a folded up pin on a character rom on the B board. Straightened out the pin and the display was back to 100%.

UN Squadron - Bad digital sound. FM audio sounded just fine, but it was overlaid by the din of what sounded like every digital sample being played at once. Reflowed the small SMD chip that handles the samples and sound was back to 100%.

Black Tiger - Scrambled sprites, no sound. Putting pressure on the B board GPU chip fixed the problem. Reflowed pins of the GPU, graphics fixed. Inspected power amp on A board, shorting pins 8 & 9 restored sound. Traced from there to bad cap and replaced. Board back to 100%.

Street Fighter 2 CE - No sound. Started at the DAC at found two dead data lines. Traced back to the Z80 audio chip, and the corresponding pins had no activity. Pulled the Z80, installed a socket and a working replacement. Powered back up and sound was back to normal.

Legend of Kage - No red channel on video output. Traced the issue back to one of the three video DACs. These are SIP packages that are hard to find, in this case I pulled one from a Rastan board that boots to garbage. If I get the Rastan booting again, I'll need to source a replacement for that board. In any event, replacing the DAC fixed the red channel and the game was fixed.

Gunbird (JP) - Sprite glitches, no sound on boot. Reflowing U3 & U15 solved the graphics problems. Manually resetting the Yamaha sound chip (U82) brought back the sound. I didn't discover the exact reason the board would boot with no sound, but connecting RESET on the watchdog chip (U20) to RESET on the Yahama fixed the problem. Some digital samples were mixed up however, reflowing U56 got the sound back to 100%.

Gaplus - Blank screen, no sound. There are three socketed 68A09 CPUs on the Gaplus board, and I found that a couple of them had their reset lines held low. Swapping the position of the chips would allow the board to boot to a scrolling playfield before resetting. Suspecting a bad 68A09, I ordered a replacement, and once in hand swapped out the suspect CPU. The board sprung back to life, and graphics & sound were 100%.

Double Dragon - Title screen was missing the left half of the twin dragons graphic, and during gameplay there were sprite and palette issues. Solved the issue by reseating one of the ribbon connectors to the video board. Easiest fix ever!

Double Dragon - Another DD board, this time the problem was video interference and the sound amp would get really hot. Culprit was a previous botched repair where the ground pad on a 470uf cap had been lifted off the board. Since the pad was toast I cleaned up the hole and then soldered the ground lead of the cap to a ground pin on the sound amp. Problem solved!

[mikemcbike]

Here you can see my arcade repair logs: http://www.wolfgangrobel.de/arcadereps.htm

[IronGiant]

Very nice, thanks!

For those who wish to view it in English, try this:

http://translate.google.com/translate?s ... dereps.htm