Show: Retro Computers

rloewy

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AJ68

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Thought it was about time to show off "the twins"... 🤪

The original pocket computers, the Sharp PC-1211 and its American brother, the Radio Shack TRS-80 PC-1, that both were released in 1980! In all fairness the TRS-80 is just a rebadge of the Sharp but it is quite nicely done!

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These were both manufactured in early 1981 so they are just about 40 years old!

Please note that these early LCD-displays have a yellow tint to them which was a filter that some manufacturers put over the displays in order to protect them from the potentially damaging effects that sunlight could possibly have on the liquid crystals! This practice soon fell out of use though as these displays proved to be quite resilient!

It is however remarkably difficult to find these in working order as these old LCD displays, if they haven't been well looked after over the years, tend to suffer from pixel-leak which starts off as a few black dots on the edges of the display that then spreads until the entire screen goes dark!

These two however are in near mint condition! And they use BASIC! 🤓
 

Erich_H

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Thought it was about time to show off "the twins"... 🤪

....

It is however remarkably difficult to find these in working order as these old LCD displays, if they haven't been well looked after over the years, tend to suffer from pixel-leak which starts off as a few black dots on the edges of the display that then spreads until the entire screen goes dark!
....
So, how does one go about "looking after" LCD displays? Is it enough just looking at them, so they don't go black from feeling lonely?

This is interesting from a camera point of view too, as @Brownie can agree to.
 

Brownie

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So, how does one go about "looking after" LCD displays? Is it enough just looking at them, so they don't go black from feeling lonely?

This is interesting from a camera point of view too, as @Brownie can agree to.
Yessir. When I'm looking at Maxxum bodies that's one of the first things I check out. I have one with a few small dots on the edge that's in otherwise good condition, but the others are all pristine. If the ad doesn't show a clear view of the LCD I don't bother looking further.
 

AJ68

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So, how does one go about "looking after" LCD displays? Is it enough just looking at them, so they don't go black from feeling lonely?

This is interesting from a camera point of view too, as @Brownie can agree to.
The key to preventing image or pixel persistence is to frequently run a program (for calculators or computers) or use any self-test function that exercises the pixels, and couple this with frequently turning on and off the device and thus the display. General use of the calculator/computer/camera will usually ensure this type of exercise of the display and keep these issues at bay!

The real problems are with displays that have been sitting unused for long stretches of time! If this is the case then you can experience a variety of issues like stuck pixels (always on), pixels not turning on (always off) or pixel leak (dark smudges covering larger areas with no discernable individual pixels in them)!

For stuck pixels, there are a variety of fixes that can help. The first and least intrusive is to use a program that exercises the pixels or to run any selftest function (like for instance for the HP Voyager series of calculators by holding the * key down when turning the calculator on) that turns on all pixels or segments on the display.

This method can sometimes also be used for dead pixels as well, so try it out and also run it several times to see if it helps, as sometimes it can take a long time for pixels to unstick or come back to life especially if they haven't been used for a while.

If these tips wont fix the issues you can try various pressure remedies. This should always be done with caution, since, if you press to vigorously, it can further damage the display, but if you are aware of the risk, this has helped me clear both stuck and dead pixels. The idea is that the liquid in the liquid-crystal may have shifted and is not getting full electrical contact, or some connection is slightly misaligned from its contact point, which can sometimes be fixed by massaging the components of the display. There are a variety of approaches to this, which include tapping, rubbing, and pressing on or around the dead/stuck pixels... carefully!

If the above wont work then IF you can open up the device and get access to the contact strip (generally a rubber "sandwich" with two isolating layers on either side of a conductive layer with a number of contact points) that connects the electronics on the circuit board to the LCD-display there is a chance that any poor connections can be fixed by running the tip of a hot soldering iron along the PCB or flexcable where it connects to the LCD in order to reflow the solderjoints! The most well known use of this last method is probably when fixing dead lines in Gameboy screens!

Lastly, the most dreaded phenomenon, the pixel leaks! When you get to the stage where there is no longer any clear pixels that are stuck/dead but rather smudges instead, there is generally nothing more that can be done to fix this, short of swapping out the display for a working one from another unit! The most common reason for this in older types of LCD displays are that the materials used to create the different layers of the screen turn brittle with time! This is even more likely if the screen is not used often as the electrical charge that runs through the display when it is used heats it up ever so slightly but enough to keep the materials flexible!

Also, in my experience, problems with pixel leaks seems to be more prevalent with segment displays (like for example Game & Watch screens, status displays on cameras, etc.) that has larger elements, than with pixelated displays like on the Pocket Computers...

Hence the recommendation to exercise your old electronics periodically to hopefully not end up with this issue in the first place!

I hope that these tidbits of wisdom can help someone out! 🤓
I myself have managed to revive quite a few calculator displays using the exercise and massage techniques mentioned above!
Just be patient! And... good luck!
 
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Erich_H

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Theory schmeory.

I got rid of a couple boring TI59's today.
With boring modules and a bunch of magnetic strips. Also boring.

Had to make room for my new C/Y mount Yashica ML macro f:4/55 mm.

Priorities. Now, if I can only find my C/Y to M4/3 adapter. Last seen at the rear end of a Yashica ML f:2.8/35 mm...
 

AJ68

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Theory schmeory.

I got rid of a couple boring TI59's today.
With boring modules and a bunch of magnetic strips. Also boring.

Had to make room for my new C/Y mount Yashica ML macro f:4/55 mm.

Priorities. Now, if I can only find my C/Y to M4/3 adapter. Last seen at the rear end of a Yashica ML f:2.8/35 mm...
Yeah... It is important to have priorities! 🙂

That is why I, first of all, have sorted out the new plug for the PSU for @Erich_H's Kodak EasyShare Printer Dock! It now turns on and completes the self test but no further testing done! Let's hope that the output amperage is sufficient to actually running it!

And it is true... When I finally took a look at the first of the TI59's it was kind of boring... Just a black slab with nothing really going on!

2021-01-15 11.18.33.jpg
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Then in a moment of pure genious I realized that I could infact open the case... Impressive awareness I know, right!?

2021-01-15 11.19.05.jpg
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Case opened at last... Tried turning it on! Still... no signs of life so I had to dig deeper!

2021-01-15 11.18.04.jpg
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And as (almost) always the battery pack had leaked! But a bit of good luck here! All of the leakage had been contained in the battery pack with nothing sneaking into the calculator! So here are the old batteries taken out and shown together with the rebuilt pack!

Now then... The refurbished BP1A pack inserted! Anything?

2021-01-15 11.20.03.jpg
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Of course... It works! 🤓

It was in all honesty not that hard of a restoration so far though as @Erich_H had kept this TI59 in a quite fantastic condition!

The only thing left to do with this one is refurbishing the card-reader as the drive wheel as (almost) always has turned to goo! Hopefully this is the last thing to do for this one before it is back to working as well as it's pristine condition suggests!

While waiting for parts for the card reader refurb... Onwards and upwards to the next one!
 
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rhe

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Playing games on a Commodore 64 in 1986...

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Zapp DJR

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Unused.
And no, I won't let anyone to peel that clear plastic off 🙃

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AJ68

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Managed to get all of the TI familymembers together for a picture!

2021-01-21 12.45.11.jpg
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The first one is the SR-50 from 1974, followed by the TI-30 from 1976 and last, but definitely not least, the TI-59 from 1977!
All of them in fantastic condition with newly rebuilt batterypacks to boot! Red LED displays never looked better before! 🤓
 
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AJ68

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I recently got some calculators and pocket computers from @Erich_H and during my restoration of them to working order I found something really interesting!
One of the devices was a Casio FX-750P Personal Computer from 1985 with a RC-4 4K Ramcard with battery backup!

2021-01-25 12.53.38.jpg
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Initially I checked it out and it was in good shape with some screws missing but nothing major! I put some new CR2032 batteries in the device but it didn't power on! This was due to the fact that the Ramcard slot lock switch was not working properly! If this switch is not detected in its proper position the device will not power on!

So I cleaned the contacts on the switch and tried again and it powered on but displayed only "???"! Some more research indicated that when the device is powered on with no working Ramcard in slot 0 it does not do anything! So I put the Ramcard in slot 0 and tried again but still nothing!!! As I read up on this system I found that the battery backup in the Ramcards were rated to last around 5 years so probably not a great possibility that anything was still going to be on the Ramcard! At least there is a capacitor in the Ramcard that allows you a grace time of about a minute to switch out the battery without it losing the contents! It is worth a shot and if nothing else I might at least get the device working again! So I swapped out the old battery in the Ramcard for a fresh CR2016 which I didn't really want to do initially as I wanted to find out if there was anything still saved to the Ramcard!

Tried turning it on again and the display changed to "P0" and as I kept digging I found that this meant that the Ramcard was detected but not available! I took the Ramcard out and opened up both the device and the ramcard and went over all the contacts and cleaned them with Isopropyl Alcohol, buttoned everything up again and tried turning it on! Success!

2021-01-25 12.49.42.jpg
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Now it at least detected the Ramcard correctly and started up! Great news!
I still wasn't feeling to hopeful about the prospect of anything surviving on the Ramcard but decided to try anyway...

2021-01-25 12.50.36.jpg
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Wait, what!?!?!? There is still something on the Ramcard!!! 😲

2021-01-25 12.50.41.jpg
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Turns out that this program was a simple program to print receipts on a thermal printer that you could get for this device together with a cassette interface!
Now I hope that @Erich_H can find that too if he still has it!

2021-01-25 12.50.46.jpg
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In the REM statement the program has the date 1993-07-16 which means that it is roughly 27 and a half years sice it was entered!!!
Wow... they really underestimated the rated battery life on the tiny CR2016 in the Ramcard!

These kinds of adventures in Software Archeology is half the fun of reviving old computers and calculators! 🤓
 
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Zapp DJR

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Thought it was about time to show off "the twins"... 🤪

The original pocket computers, the Sharp PC-1211 and its American brother, the Radio Shack TRS-80 PC-1, that both were released in 1980! In all fairness the TRS-80 is just a rebadge of the Sharp but it is quite nicely done!
...
I still have the Sharp PC-1211. However, as you pointed out, the display became completely black 😞
 

Erich_H

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I recently got some calculators and pocket computers from @Erich_H and during my restoration of them to working order I found something really interesting!
One of the devices was a Casio FX-750P Personal Computer from 1985 with a RC-4 4K Ramcard with battery backup!

View attachment 870498

Initially I checked it out and it was in good shape with some screws missing but nothing major! I put some new CR2032 batteries in the device but it didn't power on! This was due to the fact that the Ramcard slot lock switch was not working properly! If this switch is not detected in its proper position the device will not power on!

So I cleaned the contacts on the switch and tried again and it powered on but displayed only "???"! Some more research indicated that when the device is powered on with no working Ramcard in slot 0 it does not do anything! So I put the Ramcard in slot 0 and tried again but still nothing!!! As I read up on this system I found that the battery backup in the Ramcards were rated to last around 5 years so probably not a great possibility that anything was still going to be on the Ramcard! At least there is a capacitor in the Ramcard that allows you a grace time of about a minute to switch out the battery without it losing the contents! It is worth a shot and if nothing else I might at least get the device working again! So I swapped out the old battery in the Ramcard for a fresh CR2016 which I didn't really want to do initially as I wanted to find out if there was anything still saved to the Ramcard!

Tried turning it on again and the display changed to "P0" and as I kept digging I found that this meant that the Ramcard was detected but not available! I took the Ramcard out and opened up both the device and the ramcard and went over all the contacts and cleaned them with Isopropyl Alcohol, buttoned everything up again and tried turning it on! Success!

View attachment 870500

Now it at least detected the Ramcard correctly and started up! Great news!
I still wasn't feeling to hopeful about the prospect of anything surviving on the Ramcard but decided to try anyway...

View attachment 870501

Wait, what!?!?!? There is still something on the Ramcard!!! 😲

View attachment 870502

Turns out that this program was a simple program to print receipts on a thermal printer that you could get for this device together with a cassette interface!
Now I hope that @Erich_H can find that too if he still has it!

View attachment 870503

In the REM statement the program has the date 1993-07-16 which means that it is roughly 27 and a half years sice it was entered!!!
Wow... they really underestimated the rated battery life on the tiny CR2016 in the Ramcard!

These kinds of adventures in Software Archeology is half the fun of reviving old computers and calculators! 🤓
And, as I can see, I've got 27 years worth of software license fees coming if you want to continue using my program!
 

AlterKnabe

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Just a calculator, not really a computer.
But back then, I think it was 1977, the thing was absurdly expensive.
And it still works.
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