Looks like you've got some pretty ugly corrosion damage on that board.

It's also not just relegated to that one area in the middle; I believe the black sections in your traces are corrosion spots as well. The chip in the top-left corner appears to have some corrosion? A lot of your solder joints show the typical light grey damage also.

Also, what's with the discolored streak on that chip at the bottom-center? The corrosion may have leached into that IC and caused a short or damaged it in some other way.

My experience has been mostly with old pinball machines, but at a MINIMUM you're probably looking at desoldering two ICs, the resistor/diode/etc. in the center, sanding/repairing traces, and generally cleaning all the acid off the board.

Someone else probably has better advice for you, but in the meantime you might find this an interesting read:

http://pinballrehab.com/1-articles/solid-stat … -battery-damage

Those PCs really suffer from battery leakage because of its location, it's right in the middle. Out of 10, 11 have problems.
BUT, I've never seen anything like what you're describing. Yes, most probably there is some damage on the board but even in waaaay worse cases the keyboard was never affected. Actually this one doesn't look that bad. To begin with make sure there is no short anywhere before starting to look at traces. What happens when you do skip BIOS errors? Does it boot from a floppy? If so, try to check if those 3 keys work.

Man, I bought 4 of them before I found a good one. A PC to haunt your nightmares, that's what it is this little-beautiful thing...

It does not boot from floppy. The floppy motor starts but it is unable to boot. I don't think the keyboard is faulty. I have opened it and it looks fine.

Here's the three things I find the most immediately concerning.

1. Has this trace been completely obliterated? You might want to carefully clean that off with a drop of white vinegar and maybe a toothbrush or cotton swab and check.

2. Is this a short? Other photos of the same motherboard have a clean seperation between the leg and the metal plate, I'd clean that off carefully with maybe a fiberglass pencil and see what's going on.

3. Discolored streak on the IC still makes me wonder if it overheated/shorted. That appears to be a SN74F245N, which is $0.89US at http://www.mouser.com/ProductDetail/Texas-Ins … 52bxgbuIQ%3D%3D, so if you do decide to replace it you won't need to spend a lot.

Looks like you lost some VIA's.
i would also inspect the rotten one's if its only a 2 layer Board you can use a very small drill and put a small piece of copperwire inside.
Near the crystal the one looks really weird..

If the traces are broken, you can cut them out and replace them with some 30 AWG bus wire. As far as the pads go, you may be stuck. If the through hole pads are destroyed, then you have two options. Send the board to a repair house, or buy a track repair kit that has through hole parts and setting tools. Those kits start at about $250 and are getting hard to find nowadays. You would also need a set of PCB bits (little drill bits and ball mills) and a good high torque, low RPM PCB drill to drill out the pads and make the board ready for a new pad.

The reason I bring it up is the upper pad for the crystal looks like its flush with the PCB and thats a sign that there is no longer enough copper left to resolder on that side of the board. Also the trace from the diode looks like its broken at the pad. There is a dark line with a green splotch in the middle of it right where the pad and trace meet. Last but not least, the trace from the cap to the resistor looks like it may be broke at the edge of the silk screen.

Good luck fixing it, I would hate to see a classic like that get dumped.

I found the error, or maybe i should say that keenerb found the error.
keenerb's first suggestion was correct.
The trace was partly gone. See picture.

When i manually short circuit (see picture) the floppy startet to load from disk...

How do i fix the trace? This is extremely small. Any good suggestions?

Use a small bridge wire.

28 / 30 gauge magnet wire to repair the trace or do a point to point repair with small gauge wire

The trace is fixed. The computer now boot from a floppy !
But.. The Spacebar, Ctrl, Alt, Q and a few other keys to the left side of the keyboard is not working....
Ideas?

I opened the keyboard and found that i have connection between red dots, but somewhere along the path (yellow) to the pink spot i loose connection.
The second picture show where the problem is. I have scraped away the damaged are.
Is there a way to fix this?
I just found this post: https://linustechtips.com/main/topic/10836-ho … itech-g15-gen1/
Basically i need to paint the area missing with a conductive silver lacquer...

It's alive !
It's working!

1. I replaced the battery
2. I soldered the destroyed traces under the battery - with help from my good friend Francis
3. I fixed the traces on the keyboard with some electric paint

And it workes - Except RTC er resette very time i reboot machine. I will not bother to fix this - i think.
To bad i only have a monocrome screen. I tried to connect it with pin 7 on the CGA (9 pin) connector to the Composite input on LCD screen. It did not work.
I will try a CGA to SCART converter later.

Glad you managed to fix it, great work and congratulations. Another piece of computing history saved. 😀

Very nice machine! I also own one. Hercules-Gaming is cool 😀
https://www.flickr.com/photos/94839221@N05/al … th/25975356014/
http://forum.classic-computing.de/index.php?p … d&threadID=8386

Hercules-Gaming Disk included. Write back with VGACOPY.

dr.zeissler wrote:

Very nice machine! I also own one. Hercules-Gaming is cool :) https://www.flickr.com/photos/94839221@N05/al … th/25975356014/ ht […]
Show full quote

Very nice machine! I also own one. Hercules-Gaming is cool 😀
https://www.flickr.com/photos/94839221@N05/al … th/25975356014/
http://forum.classic-computing.de/index.php?p … d&threadID=8386

Hercules-Gaming Disk included. Write back with VGACOPY.

Thanks but i have only 720KB disk drive in this machine.
Is i possible to find a 720KB version (on two floppies)

dr.zeissler wrote:

Very nice machine! I also own one. Hercules-Gaming is cool :) https://www.flickr.com/photos/94839221@N05/al … th/25975356014/ ht […]
Show full quote

Very nice machine! I also own one. Hercules-Gaming is cool 😀
https://www.flickr.com/photos/94839221@N05/al … th/25975356014/
http://forum.classic-computing.de/index.php?p … d&threadID=8386

Hercules-Gaming Disk included. Write back with VGACOPY.

I have trouble reading the disk image? See error message in attached photo.

The Disk-Image is compressed. Please copy "arj.exe" packer in the Path.

dr.zeissler wrote:

Very nice machine! I also own one. Hercules-Gaming is cool 😀
https://www.flickr.com/photos/94839221@N05/al … th/25975356014/

I am trying to connect the PC to a colour monitor. I see the the Video Controll Chip has a PIN called CMPVD. Could this be Compose video output?

Do you know if anybody has tried to use this pin to get Composite video?

No, but as you can see, someone has perhaps done some other things with it:
http://forum.classic-computing.de/index.php?p … 89395#post89395

dr.zeissler wrote:

No, but as you can see, someone has perhaps done some other things with it:
http://forum.classic-computing.de/index.php?p … 89395#post89395

Yes i have seen this before. I will try to make a CGA to SCART today.
But when studying the Video Chip i found this Pin for Composite.

CGA to SCART wil proparbly give a better picture then Composite, but with composite video is is maybe possible to get more colours - as the 8088MPH demo shows. This is only possible on Composite.
Maybe you have seen this vode from the 8-bit guy: https://www.youtube.com/watch?v=niKblgZupOc

Is you the guy who made from the link that made a CGA to SCART connector?