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Roseville, CA

Posted Sat Mar 02, 2019 10:40 am

Update on this project!

While I was waiting for some replacement CIAs, a new 8701 (TOLB from Eslapion), new character ROM and an 8580 SID (I chose the FPGASID), that disgusting keyboard needed some love first.
Consider it a "microbiology study"

Some of the key posts (ESC, Help and that damn F3/F4) were either damaged previously, or during key removal. I never noticed any bits of plastic flying around but some keys were a lot more difficult to unseat than others. This should not effect key stability, but just to be on the safe side, I'll relocate those posts to lesser used keys like "line feed" and "no-scroll". I do have some spares from Amiga 2000 keyboards that use similar posts.

Denatured alcohol is my preferred cleaner for all things electronic. Industrial grade IPA is good too, but the stuff you get down at the pharmacy tends to leave film behind that you have to do a lot of mechanical removal to clean up. Denatured alcohol leaves very little residue and is less reactive to flux. In the States, it can be found easily in gallon sized containers at Ace Hardware.
Corrosion in the disco dance floor

Full disassembly revealed only a small amount of corrosion on the keyboard PCB. Compared to the horrible mylar flexible keyboard PCBs, this is easily mitigated with the fiberglass pen. The traces are healthy underneath the corroded overcoat and buzzed out healthy.

Sealed it up with two part epoxy overcoat designed for PCB repair.
Pro tip: While epoxy is setting, light heat from the rework station air gun will smooth out the overcoat.

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Roseville, CA

Posted Sat Mar 02, 2019 10:59 am

Its difficult to describe how much filth there was on the key back plate-so I was hoping my wife wouldn't notice all the funk and gunk I had to scrub off in the kitchen. I made up for it by doing a deep clean of the sink island with some bleach when I was done. So, after a good scrub, set the PCB and key housing out to dry.

Dayum that is a LOT nicer than when I started out!
Put another PCB on the barbie!

I know some people have strong opinions on retro brighting. I however, think it is the bee's knees if you can accept that there will be some need to refresh it again in a few years. Personally, I would much rather restore a computer to a near-new aesthetic and that is important to me. I prefer the liquid salon developer and not the cream variety. The cream can be the source of streaking or uneven application that is difficult to detect. Best to stick with the liquid but as you turn the keys, you will not want to be exposing your skin to it at all. Gloves and tongs FTW.
Mmmm…. keyboard lasagna!

Unfortunately, the sun has not been very cooperative this winter in NorCal, so I had to finish the retrobrite process in the kitchen. I have a large pancake plate that I can warm up on the stove and then use a pyrex dish to soak the keys in the salon developer. I've got a few grow lights that I use for indoor brightening. and mounted it to the stove. I keep an eye on the temp of the solution with one of those laser thermal probe things. The temp of the liquid should never go above 110 degrees and still be effective. Heat is critical though.

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Roseville, CA

Posted Sat Mar 02, 2019 11:17 am

Right, so the keys are looking much closer to the original creamy off white! Time to rinse and dry, and then reinstall! Drying can take days and you have to keep turning the keys because water can get easily trapped in the moldings.

My youngest offered to help out with the reinstall. He fancies himself as a gaming keyboard aficionado, and is amazed that design hasn't really changed all that much in 30 years.
The MLG takes a break from Fortnite to help with the re-key!

So, remember that missing F3/F4 key? The generosity of this community is amazing and @rpiguy9907 came through with a spare! Thank you guys so much for looking through your bins and coming to my rescue!

The finished keyboard looks gorgeous and is super clean. Unfortunately, I don't have a way to test it YET, but we'll get there!

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Seattle, WA, USA

Posted Sat Mar 02, 2019 11:29 am

Simply superb work, Toast! Wow - what a difference from that Persian rug you started from. I just love it when our kids show an interest in this stuff, too. That's a good lad there.

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Roseville, CA

Posted Sat Mar 02, 2019 11:30 am

Finally, some before and after:.
Exhibit A: "Persian Rug"


Patience, penicillin, and some internet friends made this!

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Zippy Zapp

Posted Sun Mar 03, 2019 9:24 am

Very Nice Job! I am with you on the dingy, yellow color. It was never supposed to be that way so I undo it when I can. The only thing I don't try to undo anymore is the brown keys of a C64, as I had no success doing it and caused streaking, even with liquid as I don't use cream.

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Roseville, CA

Posted Sun Mar 03, 2019 12:25 pm

@ZippyZap totally agree with you on that-after seeing some failed efforts at working on Atari 800 series keys, best to leave the keys in their natural aged color.

One thing I failed to mention earlier. Keys needing stabilizers (metal rods bent into "U" shapes) have some fragile retention clips on the keyboard back plate. Since these can break easily with age and mechanical force, I did manage to snap one end off. This can usually be avoided by flipping the key up on an axis to disengage the clip. But, it isn't foolproof and I damaged the main RETURN key's stabilizer retention. Le Sigh.

Enter BONDIC. This stuff is a UV curable adhesive that comes from the world of dentistry. It is "formable" and cures instantly when exposed to UV light. It has a subtle flexibility to it that allows it to retain some pliability after curing. It works well on plastics but with the drawback that it is not really sand-able or rigid. It is a great adhesive to have in your toolkit and I've found many uses of it-particularly in my other hobby, multi-rotor "drones". In the USA, it is usually available at ACE Hardware. If not, try Amazon (but buy local, brah!).
I also do emergency dental surgery and orthodontics repair.

By building up a small blob with the key stabilizer clip in place, it is possible to capture the clip to the plastic back plate. Quick hit with the UV light and it a light wiggle on the clip to build up a channel (to allow free movement of the clip). This worked and in seconds, I was able to hold the clip end and lift up the whole keyboard's side's weight without it breaking. YMMV, of course, but this has worked well for me on other repairs. Getting the key cap back on was delicate and best done before other keys are introduced.

If I were to need to pry the key off again, it is likely that it would need to be redone. That's probably the only downside.

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Posted Sun Mar 03, 2019 1:22 pm

Amazing Progress!

I hate and love cleaning restoring keyboards. So tedious. Love the result though.

Are you going to retrobrite the case? My luck has been mixed, so I sometimes opt to paint.

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Roseville, CA

Posted Sun Mar 03, 2019 3:58 pm

rpiguy9907 wrote:Are you going to retrobrite the case? My luck has been mixed, so I sometimes opt to paint.
Thanks again for the key, bud!

Yes, I plan to retrobrite the case as well. That might have to wait until we start getting some spring-like weather here. NorCal has had a wetter-than-usual winter so far. Just about every weekend has been wet or overcast most of the day. I know, people in Europe or Canada laugh at my whine about the weather. And Brits be like "mate, we see the sun for about 3 hours every year". But, I need some full day sun to be confident in an even exposure and greenhouse effect on the container before I will try the casing.

Cleaned up with oxi, and scrubbed lightly with baking soda, the case is discolored but in healthy condition.

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Roseville, CA

Posted Thu May 09, 2019 11:32 pm

Fast forward a few months later... getting this beast up and running took a fair bit of love, money, and patience. But, YES WE DID!
/me does a victory dance!

I was so happy when I finally saw this magical prompt. It was as if a thousand Atarians suddenly cried out... and then SILENCED!
The C128 Diagnostic Cart off of Ebay wasn't much help.

In all seriousness, I wasted a lot of time chasing rabbits down the wrong hole and fighting figments. At first I considered the Super-PLA to be a primary culprit. Then the MMU. Spent hours buzzing out traces and poking at it with a logic probe. Then it appeared that the high RAM bank was problematic when I finally could get it to boot into 64 mode but not 128.
Is that your probe, or are you just happy to see me?

Ran the pocket scope I built from a kit a few years back and it gave me some reasons to think there was some logic IC issues. After replacing those I decided to go for broke on the high RAM. Finally went down to Office Depot for to laminate schematics so I could write on them. This helped me understand the data flow and the I/O a fair bit but didn't put me closer to a solution. I even consulted the wisest of wizards in the Pacific North West. Needless to say, I was getting flummoxed.
Staring me right in the sadface :(

Oh, and did I mention that during some late night soldering sessions, I was cleaning my desoldering tool and the glass capture cylinder rolled of my workbench into a gagillion pieces? Well, that sucked because it seems I could only order replacement parts from POLAND. Nearly 5 weeks later the replacement part finally came in and I could get back to work. This gave me some time to think about the problem and it occurred to me that maybe I am looking for a complex answer when it is relatively simple: The machine boots to 64. The machine boots to 128 screen with no BASIC. Hmm.... BASIC.... Off to order more ICs from Ebay. Luckily, there's still some IC stock available of most of the custom ICs and not all of them cost an arm and a leg. One of them, the C128 BASIC ROM finally shows up and in it goes. And... we have a startup! All systems check out and, other than some very nasty jail bars, we're looking good to go.
If we're going to go for broke on replacements, let's get it ON!

Now, on to that missing SID chip! (and 8701 clock circuit). The clock circuit was easily solved by Mr. Eslapion's TOLB 8701 replacement-which worked perfectly with no fiddly. For a Canadian product, it didn't seem to mind the occasional bad "Eh?" jokes as I was installing. As in "Ya like that, eh? Feels a little snug, don-cha-know, eh?"
Don't worry, this will all hide under the RF shield! (I try to convince my OCD side that it's not that bad).

The FPGASID, on the other hand, was all business. Several jumper wires were the order of business, followed by some fiddly pin counting and corralling the excess wire. If this becomes it's permanent home, we'll look at some options for a more elegant wire configuration. For now, this will work fine.

This will do for now. After all, you are adding TWO SIDs for the price of... well, a fairly hefty FPGA price tag. But... STEREO BEECHUS!

The jailbars are next on the to do list. I ordered the C128 LumaFix, which should be coming here before 2020.

All in all, it was a good adventure in restoring a C128, my first and probably only one. I have a number of extra parts left over (need one repaired? I might be your Huckleberry). And I am thrilled with how this project turned out. Now I can turn my attention back to a non-working A2000 board belonging to a gentleman from my home state of FLA.

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