If you have the chance to own a Sharp PC-1211 (or it’s OEM version, the TRS-80 Pocket Computer – or PC-1 – sold in the US by Radio Shack), there is only one thing you are dreading: the black oil! No, the PC-1211’s liquid crystal display is not leaking when held downward, nor its keyboard is using oil for lubrication.
No, black oil comes from the alien virus popularized by the X-Files series. That black oily substance hosting the alien virus that made your life pretty miserable if you came in contact with it. Remember? Well, for the PC-1211, it is almost the same. The LCD turns black over the years. And it often does it very quickly. One day your machine is pristine, the next time you take it out of its case, damn! You are black oiled…
This is a creeping disease that usually grows from the edge of the display and invades its entire surface. Although the machine is still usable when infected, in extreme cases, you simply cannot read the display anymore, and your faithful sidekick has gone. No one really seems to know what it is. Maybe someone in the community can shed some light on our ignorance? There are many theories around. The LCD technology was so new that Sharp didn’t master it yet. The molecules are decaying over time. The environment seems to play a decisive role in the growth of black oil. Heat and hydrometry are finger pointed. Some also theorized on the yellow color of the display that makes it sensitive to UV. They have been proven wrong since, where the un-boxed system presented the defect, and when first grey LCDs started to show signs of infection. So what is it? Any ideas? I’ve even contacted Sharp and some LCD experts, but until now, no one really seems to know (or care). PC-1211 owners can only hope. But besides the black oil, this 35 years old pocket computer is still working as a charm and as a time machine to trip down nostalgia lane.
So did mine – Alien infection.
Unfortunately, it almost seems inevitable… just a question of time alas.
Mine went nearly totally black a couple of years ago. (sniff!)
P.S.: A quite curious trick for interactive games I came up with in high school, here for an invaders-like game: Have a spaceship character (mine was a Yen currency sign) moving around the line. Indicate the players position by the “deg”, “rad”, etc indicators (to emulate a second line). The trick: There was an option to map a program to a key on the tiny keyboard. So, break the running program and restart with a key (e.g., “=” for fire) triggering a tiny program as a handler that resumes the game. Now, check, if things are aligned, process, and resume.
Nice use of the def keys indeed. As well as the degrad indicator,cool 🙂
My PC-1211 is still exactly the state it was in during the early ’80 !
The yellow LCD being absolutely free of black stains, and in general: pristine condition
(no scratches). In original hardcover/sleeve, in original box w. mini programming insert.
Sealed manual set (English). CE-122 in original box (NiCad pack taken out), used but in
very good condition, and complete. EA-11E AC adaptor in original box. Service Manuals
of PC-1211, CE-121, CE-122. Box + manual for Tandy PC1 ‘clone’. Loads of books for this
model in English and German. Doc., ads, etc., etc.
AND ALL OF THIS IS FOR SALE !!! Serious bids will be considered equally. Ray
Hi Ray. Thank you for sharing your systems’ details. I am soooo happy for you. Having a prestige PC-1211 (or PC-1) is quite rare. I recently found and bought a prestige PC-1, and also started to replace the LCD of damages models (more on the later :)). I hope you are selling your pocket computer for the right reasons and won’t regret few years down the road.
Hi Jamel, Thanks for your your reply and concern. Actually this is my spare
PC-1211, and I’ve been professionally involved with SHARP pockets for more
than a decade – ending with the organizers. I’m 73 and having a load of stuff
lying around that I want to get rid of, before my children must clear out the
house … Besides I’ve had my share of fun with this first pocket computer.
As a programmer I much prefer the PC-1500A and it’s BASIC !
I would be prepared to trade-in an EL-5100, though – if the display is OK and
condition excellent, as this model was in fact the one that revolutionized the
development from calculators to pocket computers.
Very interesting that you’re able to replace ‘blackened’ LCDs. I also have an
EL-7001 Memo Writer for sale … with deteriorated (10 char.s) LCD.
Btw: the revenues for my SHARP stuff go to Médecins Sans Frontières, Ray
Thank you for sharing about your involvement with these amazing computers! I also spent most of my time with the 1500 (when I was young). I also dreamed a lot of the 1600. I could source few of these little marvels, and will share my experience with it here soon. Hope you will get the best out of your collection Ray. I assume that you are selling your spare PC-1211 on eBay. If so, post the link, so you may extra exposure.
Thanks voor your reply, Yamel.
As a professional I’ve had and used almost every SHARP-model, several Casio’s
(most of them inferior), and a few other items. In case you consider purchasing
a PC-1600, let me warn you: it will probably disappoint you. LCD and keyboard
quality are below SHARP standards. But most of all, the 1600 lacks the stability
of the 1500A. (No wonder it didn’t sell as well: it just was not the upgraded 1500,
the market had hoped for).
No, I do not sell anthing on eBay (yet ?). In my experience, selling to enthusiasts
via ‘fan’ sites is much more effective, e.g. posting on silicium.org, or one of the
German collectors sites.
If you could ‘highlight’ my PC-1211 set in any way on this site, I would be most
grateful ! If I can help you, expanding your interest in pocket computers, please
let me know. Cheers, Ray
Do a search and someone got some brand new LCDs manufactured and sells them on Etsy.
That doesn’t solve the other devices that suffer from this problem. Has anyone ever worked out how to stop this happening? I wonder if new sealant can be applied to the edges of any display starting to show a problem. Even better would be if you could squirt new Liquid Crystal in assuming the problem is leakage.
I have an EL-5100S here in which the entire left of the display has gone black. Unfortunately the display is different to the PC-1211 with DEG in a different place.
At the weekend I tried a Toshiba Libretto 70CT I bought a few years ago and the display has faded to white at all four corners. There was a slight fading when I got it but it is now far worse. Interestingly my 50CT which must be older is fine (fingers crossed).
I suppose we can’t complain too much. When LCDs first came out on watches some people (probably with a vested interest in Analogue or LED watches) were claiming that people would be lucky if the displays lasted more than a couple of years.
p.s. Ray: My late Father, an engineer who never used a computer, was a big fan of the EL-5103 and had a couple of them.
Thanks do your comments Duncan. And the tip. Yeah, I already bought a replacement screen but am procrastinating… As soon as I am done with the “surgery”, I’ll post about it. Thank you again for sharing your thoughts and experience! Cheers.
Hello Duncan, thank you for sharing this info – really surprised !
I’d probably rather my EL-5100 revived with a new LCD than my
PC-1211 – even if the DEG indication wouldn’t work properly (or
are ther more problems ?). PC-1211 maybe considered the world’s
first pocket computer, EL-5100 represented the real breakthrough
imho; as far as calculator design was involved, this was a unique
revolutionary concept. The hardware has set a new standard, but
the algorithms obviously were worthwhile enough for Wiley & Sons
academic publishers to grant the EL-5100 it’s own book !
Btw, I still have a PC-1211 with it’s pristine amber display, plus all
the other components to make it a complete computer system
FOR SALE. Please let me know, if you’re interested. I owm a lot of
other SHARP models, like EL-6200, with deteriorated LCDs.
Thanks very much, Jamel, for relaying Duncan’s message to me !
Who know what else is different with the EL-5100S ? I was about to buy the display on Etsy but decided I should have a good look of pictures of the two machines side by side. The different position of the DEG indicator stopped me from buying a PC-1211 display.. I don’t actually own a PC-1211 so I can’t compare them. Who knows if the displays are even the same size or the internal connections are the same? If someone has both maybe they could have a closer look.
Hi Duncan. Not a direct answer to your question, but this will give a peek to the 1211 display: https://jameltayeb.com/2020/07/26/black-oil/
Hello Duncan, I wouldn’t buy a PC-1211 LCD to repair an EL-5100x with. There’s not
only the matter of the DEG indicator. Though it was indeed the direct predecessor of
PC-121x , apart from both featuring 24 char. dot-matrix displays, these are different
in many other aspects. The respective display indicators are linked to mode options
set by the slide switch (and do not include PRO e.g., present on the PC-121x LCD).
I’m afraid one never will get this right. Then there is the color – i’ve seen green LCDs
offered on the Net for PC-1211, while my 2 official SHARP brochures already show
2 different colors: the original amber on the ’80 brochure, but grey from ’82 (like the
TRS-80 version). I’m not going to speculate as to the reason for this …
You may wonder, could I produce pictures ? The answer alas is no: I’m not versed
in the art of digital photography and even less in attaching skills.
I do however own a wealth of documentation, including Service Manuals for most
SHARP models. For someone seriously interested in taking some of this stuff off
my hands, I may be willing to climb the attic and dig through a few cubic meters of
SHARP gear, to see what I can find.
Thank you for your follow up Raymond. Duncan, I would, as Raymond, not advise using the 1211 LCD with another model. The computer PCB drives the LCD using zebra connectors – a flexible caoutchouc-like ribbon with conductive contacts embedded into (hence the zebra name) – which is specific to the computer and LCD model. I suspect that the signaling will likely vary between computers/LCDs, and rendering them incompatible. The yellow color of the 1211 LCD, is the result of a filter on top of the LCD. Under this filter, the LCD is grey. You can see that well on my videos. The replacement LCD has an integrated filter already. This great exchange makes me think that I should stop procrastinating and replace my LCD and share my experience with you guys here.
A soon as I saw that the indicators were different I realised the displays weren’t compatible.
Sometimes manufacturers even change their designs in the middle of a production run. I had that with a personal stereo where they switched from two belts to one, to both my surprise, and the person selling the belts..
The yellow filter was due to concerns about UV light degrading LCDs.
http://www.vintagecalculators.com/html/liquid_crystal_display_calcs.html#:~:text=At%20first%20a%20yellow%20filter,95%25%20of%20the%20new%20calculators.
I don’t think that was what happened with the PC-1211 though as people have had problems with machines that have spent 99.99% of their life in a box.
Your explanation, Yael, of what exactly goes wrong when
replacing an LCD with the wrong type is really spot on !
Good luck with your repair job (I’ve been struggling more
than once with these ‘zebras’ (Sharp ánd Casio).
Btw, did you ever read this ?
https://albillo.hpcalc.org/articles/HP%20Article%20VA022%20-%20Know%20Thy%20Foe%20A%20New%20Contender.pdf
I’ve had a number of unpleasant discussions over the years,
concerning the AOS vs. RPN battle, where outsider, Sharp,
gave the contestants a run for their money with the revolu-
tionary EL-5100 – superior in every aspect: entry logic, algo-
rithms, ergonomics and hardware package. Enjoy !
Esp. HP-fans have turned out to be a lot of snooty single-minded
fanatics
Thank you Raymond for the link to the comparison article between the 41 and 1211. I will read it tonight. Regarding your comment on past experiences confronting the advantages and disadvantages of various approaches by various manufacturers, it is indeed regrettable but it doesn’t surprise me. Reminds me of tab vs. space, etc. Some day it is amusing, some other days we just have to filter them out 🙂 What I do like though is factual comparisons. That’s what I am looking forward to reading tonight 🙂
That is an interesting article.
I said in an earlier comment that my late Father was a big fan of the EL-5103.
His job was as a stress engineer which involves lots of repetitive calculations. With the EL-5103 he could just keep changing the entries in a calculation to calculate the stress in a beam or similar. Of course a computer could also do the job but back then the computer experts would quote a month to write a suitable program, and even then there was a risk of Garbage in Garbage out or making some fundamental mistake and not realising it. With a pad of paper and a calculator my Father could show whether the beam was thick enough for the expected load in a day or two. In the early 1970s I recall him bringing home a mains driven mechanical calculator to do some work at home. Before then the Slide Rule was king.
As late as 1995 he was still being asked to do this sort of work as a consultant. Nowadays, a program like Creo probably does the calculations for you as you design the item although of course there is still the danger of GIGO.