Psion Org 1 LCD replacement

[PaulK]

Hi

Does anyone know how easy it is to replace the LCD screen on an Organiser 1 please?

Are parts even available?

Many thanks
Paul

[amenjet]

Hi

Does anyone know how easy it is to replace the LCD screen on an Organiser 1 please?

Are parts even available?

Many thanks
Paul

having a look at the Psion 1 on Jaaps site:

https://www.jaapsch.net/psion/galp1.htm

it looks like the LCD is mounted like the Psion II display with 'zebra strips'. So, it's pretty easy to remove and replace if you have the part. That's going to be the real problem. The best place to get one would be another Psion I. Some people have re-manufactured LCDs, but they are expensive and it is difficult to find a supplier who will deal with the low quantities involved. An outside chance is that one of the standard one line LCD displays that you can get has an LCD that matches the Psion 1. I'd put the chance of finding a matching LCD at about 1%, though. It might be worth a look though.

I have in the past replaced a broken LCD with a microcontroller that sits on the bus and captures the data being sent to the display controller and displays it on another display. This was on a Casio FX-702P and it displayed data on an OLED display. There is an OLED display that fits the Psion II which might fit the Psion I but it is quite a big job and you lose the low power aspect to the device as an OLED display is no-where near as low power as an LCD.

Regards
Andrew

[Martin]

Paul

Don't forget that Zac Schroff produced the 'LCD display information' section in the Organiser Technical Reference Manual. I appreciate it doesn't mention the Organiser One but it might be worth a read.

Sincerely
Martin

[PaulK]

Thanks both.

Sounds like the options are limited, and definitely out of my skill range.

The reason I ask is because someone has offered me a Psion Org 1 for £20, but the LCD has some bleeding - a dark messy splodge on the top of the display, so I was unsure if it was worth getting.

Maybe I will, and see if I can source a new LCD at some point in the future.

Thanks again,

Paul

[amenjet]

Thanks both.

Sounds like the options are limited, and definitely out of my skill range.

The reason I ask is because someone has offered me a Psion Org 1 for £20, but the LCD has some bleeding - a dark messy splodge on the top of the display, so I was unsure if it was worth getting.

Maybe I will, and see if I can source a new LCD at some point in the future.

Thanks again,

Paul

You might get lucky and find another with a good display but a broken 'something else'. There's not much information about the Psion I and it is more limited in terms of expansion and code space, but interesting for historical purposes.

Regards
Andrew

[amenjet]

This is the sort of display that I think may, possibly, be able to donate it's LCD:

https://uk.rs-online.com/web/p/lcd-mono ... lsrc=aw.ds

I don't know if Psion managed to get their own LCD made, in some ways it would be cheaper if they used an extant display like this to keep the costs down. It might be worth mapping out the connections and then a hunt can begin for a match.

Obviously, RS is at the more expensive end of the price range, ebay is the best option...

Andrew

[MartinP]

It's interesting to note that the Organiser uses the still popular HD44780 LCD driver, but many LCD modules now package this together with the LCD. So it would be possible to remove the HD44780 chip from the Psion 1 board and connect the data and control lines directly to an LCD module, although this would prevent fitting an original LCD, and it would be technically quite difficult to do the soldering.
Martin P.

[amenjet]

It's interesting to note that the Organiser uses the still popular HD44780 LCD driver, but many LCD modules now package this together with the LCD. So it would be possible to remove the HD44780 chip from the Psion 1 board and connect the data and control lines directly to an LCD module, although this would prevent fitting an original LCD, and it would be technically quite difficult to do the soldering.
Martin P.

Yes, that is another option. I hadn't thought of that. Maybe the odds have gone up to 5% of finding a compatible module. The soldering shouldn't be too bad.

Then there's the nuclear option of replacing the main board, maybe the recreated one would fit? That's not a bad option as there's very little information about the psion 1 that I'm aware of. Nothing like the Psion 2 technical reference.

Andrew

[MartinP]

I think it would be a shame to remove a Psion1 main board from its case (and maybe also a shame to remove the LCD driver IC, as I suggested), it's quite an interesting board seeing as it doesn't have the custom logic IC, it's done with standard logic chips instead. Also, there's no ROM IC because they used the 6301 version of the processor with a 4K internal ROM. But looking at the board photo, I'm wondering what they did with the 2K RAM. Looks like the chip is in the top right of the board, but there's something on top, this photo is a bit blurred, but is it 2 chips stacked together? Or is this some sort of connector?
Martin P.

p1org_ins3-02.jpeg

p1org_ins3-03.jpeg

[amenjet]

Hmm, not sure what that is, I'll have to take mine apart and see if i can tell what it is.
I didn't know they used a mask ROM, that makes it harder to reverse engineer.

Andrew