When your games go on the fritz - Suteneko's repair & mod thread.

Knights of the Round CPS1 B+C boards:

Knights of the Round is a CPS1 title that has a suicide battery and we can see that the battery has been removed from the C board and that a typical de-suicide mod has already been correctly performed to run its Custom IC sans any volatile security registers.

Knights of the Round C board uses a CAPCOM B21 Custom IC and IOC1 & C632 PAL IC which are identical to those on Street Fighter II CE/Turbo which uses a stock non battery B21, so I can easily swap over the C board onto my Street Fighter II CE B board to quickly test it:

It appears to be working so we can move over to the B board:

By checking MAME I can confirm that this Knights of the Round is missing two audio data EPROM from IC sockets 18 and 19 as well as missing a program data EPROM from IC socket 23.

Since this boards jumpers are set to JEDEC I will need to program two 27C010 for the audio and a single 27C4096 to replace the missing EPROM:

Before I program anything I use my Top3000 universal programmer to dump the contents of the program EPROM at IC socket 22, which matches the CRC of the kr_22.7f binary file from the ETC/World/US version of Knights of the Round MAME ROM set and I also dump the contents of the 27c512 in IC Socket 9 which should be audio data but appears to be corrupt and mostly blank, likely from its EPROM window not being covered and long exposure to UV light.

I completely erase the 27c512 and using the appropriate files from the MAME knights.zip I program it and the two new 27c010 with the correct audio data. However, since the B21 no longer as the volatile security keys in its memory I have to source decrypted program ROM files for the game which along with a lot of other games can be found at The Dead Battery Society.

Thankfully Knights of the Round only requires PROG ROM 23 to be decrypted so I can leave PROG ROM 22 as it is. The only unfortunate thing is that there is only a decrypted file available for the US version of this game, so I can’t get the European version that is missing the “Winners don’t use drugs” screen.

I then insert these newly programed EPROM back into the B board:

I re-insert the C board that came with this B board and test it and the game now works:

However… during playback I start noticing graphical issues, which is most noticeably affecting health bars:

And white dots around text on the character select screen:

When I originally tested the C board on my Street Fighter II CE I didn’t bother to test past the intro screen, but when I placed it back onto it to re-test it and started playing it a little, I was finding that with this C board Street Fighter II CE was also displaying odd graphical issue such as black dots above health bars:

And messed up chain fence on the Spanish stage:

From this I know that the Knights of the Round C board is bad. Both the IOC1 & C632 PAL IC are testing good and the other IC on the board only deal with additional inputs from the kick harnesses, so the only cause of the issue can be the CAPCOM B21 Custom IC which can not easily be replaced…

Placing my Street Fighter II Turbo B21 C board (and the one I used for Ghouls and Ghosts that has no kick harness for the extra buttons required for Player 3 inputs) results in perfect playback with no graphical issues:

So for now I have a broken C board that sort of almost works but since I have two spare compatible C boards I can swap them over for the moment when I wish to play Knights of the Round.

Not quite the result I had hoped for but good enough and the Ferrite Beads I had required for the B board that became Ghouls & Ghosts were donated from this C board so not a total loss.

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@Danexmurder, @Shinriji, @aidan and @matt thank you for your kind comments.

I try to make everything as easy to follow as possible and take as many pictures as possible to show what is being done, so if something isn’t clear or you want anything explaining happy to try to help.

My main tools are:

Hakko FX-888D Soldering Iron
Hakko SPPON Manual Solder Sucker
Fluke 15b+ Multimeter
Mitutoyo Digital Vernier Caliper
TOP3000 Universal USB Programmer
858D (Clone) Hot Air Rework Station
Duratool D00672 80W Desoldering Gun

I would prefer to have a legitimate Hakko 858D hot air rework station and a Hakko FR-301 desoldering gun but I just can not justify the prices for the use they would get.

Surprisingly the Duratool desoldering gun has proved to be a very good and reliable tool for me and is the most recent tool addition. All desoldering work shown thus far in this thread was all done with the Hakko SPPON by hand and was rather slow work even after getting the “knack” for using it.

I highly recommend MG Chemicals for Solder, Wick and Flux.

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Great tips here! I always love seeing what other people use for tools as well. I do a bit of console repair/mods and have dabbled in arcade stuff a bit myself. Mostly just doing infinikey installs in CPS2s although I did do one of the CPS2 HDMI mods. It’s a ton of fun!

The part where I have a LOT to learn is on the programming/flashing side of things. So far I’ve only done any of that type of things to my NESbRGB board. I think I need to set up a small dedicated PC at my workbench so I can start doing more work like you are doing here. I’d love to get into repairing and reviving old arcade games. Do you have any good resources for learning how to do things on that end?

Keep up the great work!

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I found a Hakko desoldering iron for pretty cheap. It should arrive tomorrow. My first project using it will be swapping the ROM chip from Battletoads.

I’ve also fixed a few Nintendo 64 and NES that I found for relatively cheap. Conker and Pokemon Stadium 2 were my biggest gets.

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What an amazing post @Suteneko, thank you for walking us through those different steps. :slight_smile:

SEGA Game Gear (837-7996) Refurbishment:

I had been looking for a cheap Game Gear to work on for quite a while and after putting feelers out locally I was presented with a broken one that had come out of an attic of a friends acquaintance and asked to give him an offer if I wanted it.

I was allowed to look over it for a few days and found that I could get it to power on for brief periods of time and if I tilted it to very specific angles I could just about make out video albeit with some white horizontal dead pixels in the screen, so I knew a replacement screen would most likely be necessary:

Sadly no sound was coming out of the speaker or the headphone jack, so I opened it up to check on the capacitors and it was obvious they had gone bad and where leaking so I wasn’t too concerned:

The power PCB and the Motherboard PCB didn’t seem to be in too bad shape and hardly any noticeable damage so I decided I wouldn’t mind giving this a go so offered £10 which was eagerly accepted.

Game Gears are notorious for having bad capacitors so a recap was in order.

Working on the Audio PCB:

I wanted to ensure that I could get the audio working before I invested too much so I removed the leaking capacitors from the dedicated Audio PCB using a hot air station and then cleaned up the pads:

Unfortunately the positive capacitor leg pad for C3 had lifted due to corrosion, however because the trace itself was not broken I was able to use super glue to tack it back down onto the PCB.

Audio Board Capacitor Summary:

:x:C1 - 100µf (6.3v) ~ TESTED: 116µf but LEAKING    6.3 (Dia.) x 5.8mm
:x:C2 - 100µf (6.3v) ~ TESTED: 114µf but LEAKING   6.3 (Dia.) x 5.8mm
:x:C3 - 100µf (6.3v) ~ TESTED: 111µf but LEAKING   6.3 (Dia.) x 5.8mm
:x:C5 -   47µf (4v)    ~ TESTED: 1.65µf and LEAKING 4 (Dia.) x 5.8mm
:x:C7 -   47µf (4v)    ~ TESTED: 0.27µf and LEAKING 4 (Dia.) x 5.8mm

Unlike many other I wanted to replace the capacitors with the same type of SMD capacitors so I had to measure their dimensions and found appropriate Panasonic replacements with part numbers EEEFPJ470UAR & EEEFK1C101P which were soldered in and audio was restored:

POWER PCB

I now removed the capacitors on the dedicated power PCB:

Power Board Capacitor Summary:

:white_check_mark:C5  -  22µf  (35v)   ~ TESTED: 21.18µf
:white_check_mark:C11 - 100µf (25v)  ~ TESTED: 113µf
:x:C13 - 820µf (6.3v) ~ TESTED: 815µf but LEAKING 10 (Dia.) x 12.5mm

I then replaced them with brand new ones:

If after recapping this power board you are still having power issues you should replace the Fujitsu MB3775 IC which is a switching power regulator. However all the voltages were reading fine for me so I did not need to do this, but it is probably recommended if the IC is showing any signs of burn in damage.

MOTHERBOARD PCB:

While at first glance the capacitors on the main Game Gear board looked to be okay on closer inspection you can see some corrosion on the solder joints:

However once they were removed you could see the damage was much worse:

I had to resort to heavy usage of a fibre glass pen to clean up the pads so they were good enough to re-tin them for the recap. Since the originals are so small it is hard to find replacement electrolytic capacitors that can cleanly replace them:

Due to the clearance available you can take some liberties and use up to 6.3mm diameter capacitors and aim to find 5-6mm length capacitors that can easily fit in the original positions. However for the C44 and C45 0.47µf capacitors I was unable to locate small enough capacitors in stock anywhere so I had to leave the capacitor legs longer to allow me to position them flat in new positions that wouldn’t obstruct the closing of the case:

Also even with a 5mm length capacitor at position C6 it will end up resting on top of the SEGA ASICs so I left the legs longer and bent them to allow a better resting position for it as well:

Motherboard Capacitor Summary:

:x:C1   -  33µf (6.3v) ~ TESTED: 310nf
:white_check_mark:C3   -  10µf (6.3v) ~ TESTED: 11µf
:white_check_mark:C6   -  10µf (6.3v) ~ TESTED: 11µf
:x:C31 - 100µf (6.3v) ~ TESTED: 0.03nf and LEAKING
:x:C35 -  4.7µf (35v) ~ TESTED: 1.36 and LEAKING
:x:C37 -  68µf (6.3v) ~ TESTED: 0.03nf
:x:C39 - 100µf   (4v) ~ TESTED: 122µf
:x:C44 - 0.47µf (50v) ~ TESTED: 1.15nf and LEAKING
:x:C45 - 0.47µf (50v) ~ TESTED: 71nf and LEAKING
:white_check_mark:C48 -  10µf (6.3v) ~ TESTED: 8.4µf
:x:C49 -  22µf (6.3v) ~ TESTED: 0.23nf and LEAKING

After I confirmed everything was working after the recap, I used my hot air station on the ribbon cable connecting the original screen to the PCB and removed it along with the CFL back-light and various components that would no longer be required for the replacement screen:

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Cleaning and preparing the Game Gear:

A plastic pry tool was used to gently remove the original plastic lens from the front of the case:

The speaker was also removed by clipping with side cutters the bonding holding it in place circled below:

For the rear part of the case the battery terminals were de-soldered and removed so minor corrosion could be removed:

Leaving the Game Gear case bare and ready to be washed, then buffed with Novus plastic polish:

The battery terminals were then re-inserted and their wires re-soldered and used new heat shrink tubing to cover the internal metal contacts, then the recapped audio and power boards were re-inserted:

Because the original plastic lens has a deep scratch in the center of it, that no amount of buffing would remove without also destroying its decal. A replacement glass lens was purchased and carefully mounted taking care to line up the Power red LED.

Sadly the decals on these glass lens are noticeably different to the original when put side to side:

Replacing the Speaker:

Since the original speaker was a bit tinny and distorting a little at high volume I decided I would try to find a new and better replacement for it. For that I needed to find out its dimensions which I measured with my digital vernier caliper:

The original measured at 28mm diameter and a 4.5mm thickness and according to the Game Gear service manual is 8Ω (ohm) 0.15W speaker. I was unable to find a replacement with the same depth, however there is just enough clearance to allow for an extra 1mm in thickness.

So I ended up buying a RS PRO 8Ω 1.5W Miniature Speaker with the measurements of 28mm x 5.6mm which is a tight fit:

Due to the new speaker not having as big a notch as the original I had to cut out the notch in the case using side cutters as circled below in red:

I then transferred the wires across from the original speaker and re-mounted it in the case with the speaker holder being bonded back into place with quick dabs with a hot soldering iron:

Replacing the Screen:

I purchased a McWill Game Gear LCD-Mod from Dragonbox.de. These screens are now heavily being cloned in China so beware of cheap clones that are flooding the market!

I will not go into the details of installing this screen mod as it is quite a complex mod and there are detailed instructions out there for you to follow.

However, the mounting points that are suggested in the official guide are far from ideal and I ended up locating better soldering points to tap from.

Alternative soldering points for PCB revision 837-7996 only:

D1: Bottom of Resistor at position R54
D2: Bottom of Resistor at position R57
D3: Bottom of Resistor at position R55
D0: Right hand side of Resistor at position R56
DW: Bottom right corner of SEGA ASIC 315-5378A

You also need to be very careful about the thickness of the wire you will be using and I’d highly recommend using 22awg stranded wire.

Thinner gauge wires seem to cause problems especially if the wires are placed close together as then interference between them can cause the screen to not function.

The completed McWill Screen Mod:

I now re-assembled the Game Gear and all is good:

Close up of the new screen:

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Notes about the OG Game Gear Screen:

POLARIZING FILM:

If you find it difficult to see the screen without tilting the Game Gear to awkward angles (like was the case with mine) it is highly likely that the polarizing film has gone bad which is not uncommon.

If you are very careful you can use a craft knife to lift it up at a corner:

You can then peel it back by hand to remove it:

You should then repeat the process to the rear of the screen where there is a second filter:

You can then buy replacement polarizing film to cut to size with which to replace it.

Sadly my original screen can not be saved due to it having dead pixels.

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Lazarus Game Gear brought back to life. Great stuff.

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It’s the uneven pixel scaling a result of the new screen or is it the game?

It is the fault of the modern screens scaling the Game Gears 160 x 144 resolution to its native 320 x 240 resolution. Sonic games tend to show it up worse than others for sure though.

So you can notice some weird shimmering when horizontally scrolling which is off-putting at times.

You can hold start + buttons 1 & 2 to change modes and even set it to 1:1 pixel scaling which gives you a postage stamp sized image with square pixels instead of the original Game Gears rectangle pixels but any funky scrolling artifacts disappear.

The screen holds up much better with Master System games as you can play them at the original SMS resolution on the screen which is rather lovely to see on a Game Gear.

Sadly there are no other replacement solutions out there right now and this is far better than nothing.

BenVenn is supposed to be working on a new replacement screen for the Game Gear but seems that project has been stalled for quite some time and will probably be a limited production run.

I can’t recommend the McWill LCD screen mod as a replacement unless your original screen is faulty.

That said the original screen is a blurry washed out mess at the best of the times and that CFL back-light sucks up lots of juice… So fingers crossed BenVenn solution comes to fruition and ends up being better overall solution.

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Really awesome write up! What tool are you using to test capacitance?

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Awesome work!

I was wondering why you were digging around for capacitor info. I figured console5.com had a cap kit for it, but it looks like they don’t have one for that model. I didn’t realize there were hardware revisions on the GG given its short life span (seemingly, without looking it up).

My parents shipped my GG to me years ago and they didn’t put much effort into the packing so it arrived with a cracked screen and there’s definitely something wrong inside too. The screen was all borked, likely cap issues as with all GG’s

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Well to be fair the capacitor kits that are out there all use the cheapest caps available and install messily because they are all standard 10mm+ length caps. They even replace the SMD ones of the audio board for standard through hole electrolytic capacitors which is a poor idea due to the lack of clearance in that area. It would be very easy to short them out if you are not careful.

So didn’t find that satisfactory for myself and it is not hard or expensive to build your own cap list to include best sizes and high quality parts and then order them from a local supplier.

Sadly just using my Fluke Multimeter in capacitance mode so I can not see ESR readings to tell if the ones that still measure good are still 100% good to re-use. Would love something like a Peak Atlas ESR70 but hard to justify the cost.

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Interesting, I’ve never recapped anything. RC car electronics soldering is my main experience soldering, but I guess I thought they were well regarded cap kits. Good to know if I attempt to improve my soldering skills. Thanks!

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Put a new shell on my gba I got earlier this year. The old shell was missing the battery cover and was extremely yellowed. It almost feels like a brand new system. I’m really considering buying an ips screen for it.

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You have no idea how happy I am right now. I bought god of war ps4 pro a few weeks ago for $235. The listing said it had no video. I assumed it was the hdmi port. When I got it my suspicion was correct since there were bent pins in it.

My first attempt at changing the port went okay. I added low melt solder to the pins and used a hot air station to remove the port. I was surprised at how much heat I had to pump into the board so I was afraid I damaged something. When I put the new port in I plugged it up and there was no video. Turns out I had the wrong port since ps4 and ps4 pro ports are different.

A week later I get my new port. I decided to use a magnifying glass and my cheap soldering iron to solder each pin.

Sure enough when I plugged it in this time I got the PlayStation logo. It’s such a great feeling trying something new and having it actually work.

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Wow, awesome!

Now that is one expensive gamble and glad your assumption was spot on!
Good work :slight_smile:

SEGA Mega Drive AC Mains Adaptor (1602-05) Refurbishment:

Model No: 1602-05
Input: 240V 50Hz
Output: 10v DC 1.2A
Polarity: Center Negative

To open these SEGA power bricks up you will need a 4mm HEX driver.

However finding one that can open these can be quite problematic due to the depth of the holes and them only being 7mm in diameter:

I searched through quite a fair few tools before I found one that would be suitable to open these.
I recommend using a Wera Kraftform Micro Series 2069 05118120001 Nutdriver HEX 4.0 x 60mm

Now that it is opened up you need to de-solder the two points circled below:

Which separates the small PCB from the transformer leaving you with:

You can immediately see the capacitor has been leaking and that the power cable that is connected at C1 is frayed a little. This is the third SEGA mains adaptor that I have opened up and this has been the case in all of them so far.

While it is not necessary I de-solder all components from this small PCB as I intend to replace everything:

Original 1602-05 Component List:

  • 1x 3300μF 16v Capacitor
  • 4x 30D2 Switching Diode
  • 1x 390Ω Resistor

WARNING!

The US 1602 AC Mains Adaptor uses slightly different components:

  • 1x 3300μF 16v Capacitor
  • 4x Switching Diode (unable to confirm type)
  • 1x 750Ω Resistor

Here is the reverse of the PCB for anyone that is interested:


NOTE:
As mentioned previously it is not necessary to replace everything. The only thing you really need to replace is the single capacitor unless the other components have burnt out in which case the mains adaptor would not be working to begin with.

30D2 Switching Diodes are no longer being manufactured and are very difficult to find. These four diodes are performing the AC to DC conversion which is known as a “full-wave bridge rectifier”.

A suitable modern replacement for these are 1N5408 Switching Diodes.

For the 390Ω resistor I replaced it with a modern and more efficient 390Ω 1W Metal Oxide Resistor.

After cleaning up the PCB and slightly cutting back the frayed wire ends I re-assembled the small power PCB with the new components:

OPTIONAL STEP:

If your transformer is showing signs of rust you can also remove that by de-soldering it from the plug connectors circled below:

You can now easily use some rust removal jell on it if it is really bad or just lightly linish away the rust:

If you do this remember to replace the clear plastic piece to the bottom if it is present or just wrap it in Kapton Tape if it is not. And ensure you re-connect the polarity correctly!

TESTING:

I tested this power adaptor before and afterwards within my limited means and these were the results:

BEFORE:

  • DC Voltage (Unloaded): 13.30v
  • DC Voltage (Mega Drive Load): 10.90v
  • AMPS (Mega Drive Load): 0.8a

AFTER:

  • DC Voltage (Unloaded): 13.40v
  • DC Voltage (Mega Drive Load): 11.00v
  • AMPS (Mega Drive Load): 0.8a

Not really any change for the better or worse.

CONCLUSION:

It is well worth opening up your SEGA AC Mains Adaptor to change the 3300uf 16v capacitor that will be at the end of its life and sort out any frayed power cord wire ends, but everything else you can just leave alone unless there is a problem.

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