A laptop needing help. The Acer K385s, screen rebuild (Part 2)

 Today is tomorrow, and after some rest I set about replacing the front polarizer. Some notes on how it went as I got it on:

1: Do as absolutely perfect a job of cleaning the screen glass as possible before starting. Wash your hands with dish soap, use an air duster to clear any tiny motes. While the film seems to be just gas permeable enough to let you slowly work out bubbles, it's slow going and if you badger it enough you chance leaving scuffs. If there are any bits of dust left on it, they will act as a tent pole to hold a bubble open even if you burnish it til the cows come home.

2: I absolutely forgot to orient the two sheets of polarizer 90 degrees to each other when I put on the front and didn't notice i'd done so until i nearly had the whole screen assembly back together. Turns out in this case it doesn't seem to have mattered appreciably. PHEW!

3: taking photos all along the way is your friend when trying to remember the exact way every bit was originally.

It's not nearly so difficult to see in person, and comparing it with my "before" picture, it's not that much less crap looking anyway. Thank god for modern screen tech.










NEXT! with screen-shenanigans sufficiently sorted, it's time for looking into why this little beaut won't boot. I suspect the floppy drive has a tummy ache, and since the hard drive boots a desktop with a pile of adapters getting it to normal IDE headers, I'm thinking the Dallas clock chip might be borking up the boot process. I've never neutered a dead battery from out of one of those before, and I'll update as that plays out, but I guess before trying to get it any further it'll have to be done. Updates to come....

A laptop needing help. The Acer K385s, screen rebuild (Part 1)

Got this little 386 laptop from the Atlanta Historic Computing Society's free tables at their monthly meeting.It's an Acer AnyWare from 1992 with a 386 processor and 2mb of ram. Physically intact but sans battery, charger, or any documentation. Given many many early 90s laptops are crumbling to dust and plastic crumbles here 30+ years later, this little guy struck me as a trooper and deserving a bit of trying to bring it back to life, if only to take in the process.

I managed to get it booted after a bit of research, though i didn't find much about it other than the charger's output voltage pinout online, which was critical.

The lower text is from an stale old ebay description, and the Acer Anyware K386s apparently was also sold as the Acros 325SE. As far as I can tell Acros was it's own company Acer bought out around 1992, and like HP and Compaq in the mid 00s, the model naming got muddy in the merger for a bit.

With correct voltage in hand and some helpful scribbles from a previous owner on the underside where the battery once went, I bonked on a bench supply, and hoped the very simple nature of the old NiCd battery would let it wake up on life-support.

 

 

 

 

 

 

 

 

The screen is in bad shape, a typical breakdown of the light polarizing front and back layers of the LCD commonly called "vinegar syndrome". The polarizing material breaks down to acetic acid and stops working correctly. It can be fixed, but is typically very delicate and intensive work to do.

So fuck it, we ball. If slathering old plastic in hair bleach and peroxide does wonders for old plastics, tearing old LCDs to bits and slapping on new tint like it's a Dodge Neon is probably a good idea too right?

So I asked a few questions on the AHCS discord, lurked a bit on a user going by techknight who's replaced similar polarizer issues, and ordered the finest, cheapest ebay polarizer sheets that seemed likely to be large enough. I also ordered up the adapters needed to stick this computer's 80mb hard drive into a desktop pc of the late 90s, and a compactflash card adapter to replace said hard drive if it were borked, since the machine didn't want to boot into DOS before. The drive sadly just had a nearly-bone-stock install of DOS 5.0 on it. Computing archaeology is sometimes very bland that way.

 

Five screws hold the lower hinge assembly with HV backlight driver, contrast controls, power button, and lid switch. To access two of them you need to gennnntly bow up the rear port cover and slip it out.

Getting the front and rear bezel of the screen apart requires two screws from the hinge edge of the screen and lots of gentle prying, popping, and wiggling, in addition to removing the left hinge and it's cover.

With the RF shield off, the screen is tidy, and has an odd little back-bend cable on the screen ribbon. funky.

Much fiddling, gentle prying, wiggling, and cajoling later, and i had the screen mostly free to remove the front LCD polarizer. Metal screen frame is just held to the plastic screen frame with bent tabs.

A breather mid-surgery. Peep this oddly repairable and modern size of ram stick lil dude is sporting! Two whole megabytes!

 

 

 

 

 

 

 

 

It's nerve wracking taking a razor blade and pliers to a very well stuck bit of paper thin glass, but the top polarizer came free without much fuss, just a lot of slow but strong pressure pulling it up after scraping loose one corner.

 

 

 

 

 

 

The rear polarizer was much more involved to remove. The two boards that drive the vertical portion of the screen were hugging the screen's frame with their delicate flex cables held to the glass by conducive glue. Break the ribbon or glue bond and it's a dead screen. To even get those free i had to use solder wick and detach the ribbon cables tying them to the horizontal screen driver board.

Sneak a pointy razor under one edge and pull up firmly, but smoooooooth. let the pulling do the removing, this isn't like ripping off a bandaid. let it come up at it's own pace and pull just enough to keep it coming up. be careful when it's close to finished that it doesn't come flying off.

Now to "play dodgeball in a minefield", as one person from AHCS put it, who's done similar repairs. "Vinegar syndrome" is a very apt term for this effect. As soon as i got the corner of this side up the stank was strong. With the plastic sheet off, next is a scraping razor, goo-gone, and patience to get the old polarizer off.

This pic should be last. the glass sans-polarizer on both sides is nearly perfectly clear. At the edges you can just make out a bit of the conductive layer of the glass.

Half the help i got for removing and reapplying this film was a bunch of videos some dude in what looks like SE asia/oceania put up that's just absolutely manhandling modern big screens with fried polarizers with the sort of skill Turkish ice cream vendors use to play with tourists.

Worth a watch!
https://www.youtube.com/watch?v=K-0u9FqI5oM

If you plan on trying this, make sure the glass is resting flatly against a smooth, clean, flat surface. That's likely the most critical thing to not cracking it. Be very careful to not disturb the ribbon cables any more than is absolutely unavoidable, and clean the whole thing with rubbing alcohol as absolutely spotless as possible after cleaning the adhesive before reapplying the polarizer.

Photos out of order lulz.

After all that msesing around, I reapplied the new polarizer sheet to the rear and reassembled just enough to see if I had destroyed the screen along the way. I DIDN'T!

These early passive-matrix LCDs were always tough to photograph and see, and modern TFT polarizers are a bit different, but all you can get your hands on anymore. I had to get ones meant for a much later screen and cut them down to fit this one. To work correctly you need to orient the two layers at opposing orientations, for maximum contrast. Ideal orientation depends on the exact screen and polarizer but i only had one option since these sheets were only just big enough to fit one of two orientations. at 0 degrees opposed or 90. I managed to totally goof on flipping them 90 degrees to each other as I cut out and put the front layer on, and didn't catch myself until I'd fully reassembled the whole screen and hinge assembly. Thankfully on this screen it doesn't seem to have affected the display in an appreciable way.

I've been told that the ideal angle for these is 95-105 degrees opposed, and a bit of rotating the unadhered polarizer sheet makes that seem right, with a slight improvement in contrast, but these old screens were made expecting a phase correction layer and different polarizer formulation than is available anymore anyway, so it'll never look factory perfect again, and I'm okay with it as-is. Trying to redo it again seems like a recipe for accidentally breaking something irreparable.

Once today is tomorrow I'll take a crack at properly applying the front polarizing film, hopefully with fewer spots and bubbles from imperceptibly small dust than the backside, then move on to why the machine won't boot, why the floppy drive grinds on constantly like a dying case fan, and maybe some day draft up a new battery for it since even dead ones are nigh-undocumented online.

Random Projects in the last many years

 First, a Raspberry Pi emulation console for my older brother Roger, with a library of games chosen for the when he was a kid/teen.

A Gameboy Zero build I made around 2018. so many wires inside....

In late 2018 I got an interest in laser cutters, and Freeside had a spare one in need of new guts, so I taught myself to repair it and use it at the same time. New motor control board and everyone else at the space benefitted as well!

Freeside held an event called the artist's garage sale, so I made a light-up sign for it. I used a projector with a picture of a typical garage sale sign at an angle to help mark out the stretched off-kilter look of the sign, and it doubled as a small whiteboard.

Got into a cyberdeck kick for a while, and this is HackyPuff Jr, which was meant to let me excise all the more sloppy hacky means of making one so I could focus on a more refined cooler slicker one that's still incomplete. https://hackaday.io/project/175161-hackypuff-jr

A copper axe I made in the style of the one found with Otzi the Ice Man

Other random odds and bobs:

RickyTV 2021

(This article was originally posted as a build log here in late 2021: https://hackaday.io/project/182946/logs)

THE GHOST OF CHRISTMAS PAST....

My brother Ricky is HARD on video players and media. Really hard. Since we were kids he'd watch one spot of a tape until it snapped and broke in the VCR. I grew up figuring out how to splice and extract busted tapes, reset VCRs, and intuited not to touch the big red wire inside his TV/VCRs well before I had anyone who could tell me the angry pixies were hiding under that suction cup.

The VHS era was great for folks of limited mobility or cognitive ability. Stuff chunky plastic tape into hole, watch video. Simple. DVDs made the care and feeding of video media much more difficult for folks who can't understand or aren't able to avoid scratching, smudging, or otherwise being rough on DVDs and DVD players.

In 2013 I built Ricky a small "arcade cabinet" with a modified 5-disc DVD changer inside wired to arcade game buttons for controls, and this served him well for several years, but nothing lasts forever, DVD's heyday came and went, and an unfortunate incident with chocolate milk spilling between the cracks ended the DVD player's tenure.

Ever since my family should have purchased stock in various DVDs he's been fond of. Lilo and Stitch, Knight Rider (with the 'hoff of course), and others. I've also worked with hackerspace friends to roll up various Raspberry Pi based video player solutions for Ricky, some of which even lasted a year or two under his heavy use.

I didn't get to see him all of last year, and this year for Christmas I'm bringing him a new player.


BACK TO BASICS

One serious hurdle to making Ricky a solid video player is his ability to understand it's usage grammar. I'm not sure if this is the correct term in engineering design, but it seems correct to me. If there are menus he might get lost, if button presses don't quickly yield some change he gets frustrated or confused. Sometimes the same goes for his caregivers, be they family or helpful nursing staff. You can't blame someone who's confused at how to make a one-off prototype machine behave if it doesn't do what they expect other similar machines to do.

To that end I've tried to make simple, flat, simple interfaces in previous players, but sometimes prototyped machines do strange things when I've already driven home several hours away and that's a sad time for everyone. This time around I'm essentially outsourcing the video player design to an inexpensive no-name USB/SD card video player.

With some setting fiddling this player seems to be great for what I need. Autoplays anything plugged into it, outputs video to HDMI and audio to RCA plugs without a fuss. Only trick is some of the most needed buttons only live on the remote. Well balls....

It's not the end of the world that the controller is the only way to get at the fast forward and rewind buttons. I'm a fairly dab hand with an iron, so I gutted the controller, charted out what pins on the control chip do what, stuck it on perfboard with some Wago-style spring terminals to make running out to other buttons easy, and got out some small wire and the 60/40.

With a little testing I've now got easy access to run the most important buttons remotely without worrying about tearing the gossamer thin traces from this cheapie single-sided remote control board. Also I added connections to run it from a 3vdc wall wart so batteries in the remote aren't of concern.

Don't forget the intrinsic documentation. The next poor asshole working on it will thank you, and it's likely to be you anyway....


BUILDING THE CABINET

With all the main parts ordered or on-hand, tested, and everything working on the test-bench, it's time to make something that can take a licking and keep on playing, and that starts with the cabinet. I've decided to plagiarize TV design from the late 80s to the mid 90s and just make a simple boxy thick box. a PC monitor will mount in the front, the electronics will be mounted to the sides or bottom of the cabinet, and the whole thing will be constructed of half-inch ply with a removable back for servicing.





WHAT KIND OF "TAPES" ARE THOSE?

The format wars have not been kind to special needs folks. With added complexity, features, more compact shapes, and the like comes fragility, more difficulty in understanding, and frustration if things don't behave the same every time you try to use it. The VCR blinking 12:00 was innocuous enough, but how do you explain to a toddler they can't watch their favorite show because their disc is scratched, they're in the wrong menu, and besides that, the TV was set to the wrong input?

Well the first thing you can do is make the physical media harder to damage or use incorrectly. Over the years I've tried hiding the media in a cabinet, keeping it in the SD card or USB stick attached to a Pi, but you know? VHS tapes were pretty robust, what's a similar take for the modern era?

While doing my day job I noticed this audio player in the homes of some visually impaired older folks. Turns out the library of congress makes these audiobook players for folks with poor sight, and these cartridges that are basically USB sticks in a chunky case that only goes into the player one way.

A couple of years ago I made a video player by modifying one of these and using the cartridge port, but the raspberry pi software I'd used didn't get much time to test before covid, and unfortunately the player got cranky after I left . *sigh*


SCREWS AND GLUE

Decided to forego the corner pieces of the cabinet to leave a little more wiggle room since after edge-screwing the cabinet together it was plenty sturdy. With a bit of superglue around all the seams to help hold it all rigid, I was left with a box with a hole in it.
From there I realized I'd left most of the guts meant to go into it except the screen at my hackerspace (shoutout Freeside Atlanta!), so rather than my usual methodology of "smash all the parts in and make it go BRRRR" I took a more metered approach and filled holes and rough spots, sanded it smooth, and then installed the screen since I at least had that with me at home.

Sometimes I'm a clever duck. As I was trying to decide how to best mount the electronics to the inside of the case it occured to me I can just screw a board to the screen's VESA mount and stick most of the guts of the player to that, so I did.

The punch list is getting shorter now. As you can see I've added label inserts to the button faces. I've also taken the liberty of making a clear acrylic screen cover I'll attach soon, it could use some vent holes and a fan for the backside to keep the screen from slow-roasting itself, and then there's just that cartridge port that need to hurry itself up and get here before I need to head down for my visit....


(The USB cartridge slot ganked from a talkingbook player. Is it a karmic injustice to make a media player for disabled folks from a media player for disabled folks? If so I'll be in for another round of samsara I guess)


So it plays great, looks pretty good, and I've written a decent essay on it. What next? Well if the past is anything to go on I can expect a phone call in a week or month or year asking for help to get it going. I've built it as well as I can in the few weeks of free time I've had to make it, and given this is the..... 7th? iteration of custom video player I've built him maybe this one will last longer than the other s have? Only one way to find out!

(UPDATE For 2024: The player has been working without any help from me but bringing Ricky fresh video carts when they get lost. A new record for his media players of any stripe going back all the way to VHS tapes!)