HP-95LX palmtop personal computer: A blast from the recent past?

[jebem]

Recently I saw this machine for sell at a local auction site.
Not working condition. Sold as is. Manual included. No returns.

This brought me memories from the good old days when the IBM PC DOS 1.0 was a kind of a new frontier in "affordable" computation.
At the time I was working for WANG Computers and we also had our Wang PC on the market and despite not being compatible with the IBM PC BIOS, it run Microsoft DOS 1.22 initially and was more powerful thanks to a real 8MHz 16-bit 8086 processor and a more advanced I/O architecture.

Well, the HP-95LX English User's Guide alone is worth the asking money, so I bought it.
It arrived today.

The printed manual surely is the heaviest I own from HP - 960 Grams!
Adding the Quick Reference Guide and I have got more than 1 Kg of printed paper!

After a brief inspection I saw the problem: Battery corrosion once again caused contact isolation.
Just for testing, I cleaning the contacts just enough to make sure the power supply would not be the root cause.
Plugged in two AA batteries and voilà, it booted nicely!

How simple the world was in the 80's.
An small OS (for Microsoft, that is), probably only beaten by my Sanyo 64KByte CP/M OS running on a Z80 processor.


Battery corrosion ugly head:




Self Test passed with flying colors (Esc + ON):




And the so called Easter egg inside the self test procedure:

[Thomas Klemm]

Nice finding. Recently I stumbled upon W - A simple programming language. Just in case you want to write programs for it.

Cheers
Thomas

[Bill (Smithville NJ)]

(12-14-2015 11:48 PM)Thomas Klemm Wrote:  Nice finding. Recently I stumbled upon W - A simple programming language. Just in case you want to write programs for it.

Cheers
Thomas

I agree, the HP-95LX is a great little computer. You might want to get a SRAM memory card to put in the slot. I think ACE made a driver for a flash card also.

Thanks for posting the link to 'W' - I had never run across that before. I may have to dig my HP-200LX out and give it a try.

Bill
Smithville, NJ

[jebem]

(12-14-2015 11:48 PM)Thomas Klemm Wrote:  Recently I stumbled upon W - A simple programming language. Just in case you want to write programs for it.

Thank you, Thomas.
I had a brief look to it and it seems to be a really tiny compiler - about 50KByte, so it can run natively in the 95LX environment.

Although I still have to restore my 95LX, later acquire at least one RAM card to have some more memory space, and then build a USB-RS232 serial cable (I know I could buy one ready made, but it would take out all the fun of this hobby).

Yesterday I have opened it. This will be a partial tear-down only.
HP keyboard assemblies based on plastic heat stakes, like this 95LX, gives high structural rigidity but it is a pain to do proper maintenance when needed.

I was lucky as the battery acid didn't reach the main electronics.

[Dave Frederickson]

(12-15-2015 09:04 PM)jebem Wrote:  ... later acquire at least one RAM card to have some more memory space, and then build a USB-RS232 serial cable

I use a Compact Flash card and a PCMCIA (People Can't Memorize Computer Industry Acronyms) adapter in my 200LX. Haven't the need for a cable.

[jebem]

(12-15-2015 09:21 PM)Dave Frederickson Wrote:  

(12-15-2015 09:04 PM)jebem Wrote:  ... later acquire at least one RAM card to have some more memory space, and then build a USB-RS232 serial cable

I use a Compact Flash card and a PCMCIA (People Can't Memorize Computer Industry Acronyms) adapter in my 200LX. Haven't the need for a cable.

Indeed. And the speed transfer should be higher too!

[Bill (Smithville NJ)]

(12-15-2015 09:21 PM)Dave Frederickson Wrote:  I use a Compact Flash card and a PCMCIA (People Can't Memorize Computer Industry Acronyms) adapter in my 200LX. Haven't the need for a cable.

The HP-200LX is great in that it supports standard flash cards.

But flash cards are a little more iffy on the HP-95LX. See the following link to using CF cards and their limitations on the 95LX:

CF Cards on 95LX

I used to have an USB PCMCIA external card reader that worked with windows. When the drivers were installed, I could read SCRAM cards as well as flash cards.

Bill
Smithville, NJ

[striegel]

The keyboard is not permanently melted together. You can disassemble it by pushing out each one of the small plastic pins with a pin punch or similar tool.

See the helpful instructions for palmtop disassembly on Daniel Hertrich's site.

(12-15-2015 09:04 PM)jebem Wrote:  ...
Yesterday I have opened it. This will be a partial tear-down only.
HP keyboard assemblies based on plastic heat stakes, like this 95LX, gives high structural rigidity but it is a pain to do proper maintenance when needed.
...

[jebem]

(12-16-2015 02:35 AM)striegel Wrote:  The keyboard is not permanently melted together. You can disassemble it by pushing out each one of the small plastic pins with a pin punch or similar tool.

Thank you for the info.
Yes, I was incorrectly generalizing in excess!
In this case, it seems that the plastic rivets are not melted down.

However, to access the keys we need to remove the front keyboard plastic cover, and it seems to me that the only way to do it is to somehow destroy the original integrity off the machine, as it appears to be glued.

Did you try it yourself?

Normally we end up with a more or less damaged front panel that will never be the same as the original, unless you are very lucky or very skilled!
I have destroyed a couple of HP-17B and 32SII by doing this procedure.
So, I only peel of these glued front panels when I really need to access the inside components for repair.

[striegel]

The plastic overlay surrounding the keys is strong and flexible and the adhesive holding it down is not overly aggressive, so it can be removed without doing any damage to it. This is not like the metal overlays used on the older HP calculators.

I have done this on multiple 95LX/100LX/200LX machines over the years - removing them without applying any heat - and never had one get creased. If you are careful, the overlay can even be put back into place without applying new glue.

BUT... don't try to clean the old adhesive off the back of the overlay with any solvent. That can dissolve the printing right off the back of the plastic. If the adhesive is too dry and will not hold, you can lightly scrape with the edge of a knife and pull off any lumps (like with tweezers). Then maybe some thinned rubber cement would be best to glue it back down.

On one 200LX that I moved into a 100LX's case, I used 1/8"-wide Scor-Tape double-sided adhesive tape to re-attach the overlay.

(12-16-2015 01:33 PM)jebem Wrote:  ...
However, to access the keys we need to remove the front keyboard plastic cover, and it seems to me that the only way to do it is to somehow destroy the original integrity off the machine, as it appears to be glued.

Did you try it yourself?

Normally we end up with a more or less damaged front panel that will never be the same as the original, unless you are very lucky or very skilled!
I have destroyed a couple of HP-17B and 32SII by doing this procedure.
So, I only peel of these glued front panels when I really need to access the inside components for repair.

[jebem]

(12-16-2015 01:56 PM)striegel Wrote:  The plastic overlay surrounding the keys is strong and flexible and the adhesive holding it down is not overly aggressive, so it can be removed without doing any damage to it. This is not like the metal overlays used on the older HP calculators.

I have done this on multiple 95LX/100LX/200LX machines over the years - removing them without applying any heat - and never had one get creased.

Great information, Thank you for sharing!

By the way, did you succeed at any point to install and setup a flash PCMCIA memory card on the 95LX?

From what I have been reading it seems that it should be possible using specific brands and specific drivers, but I would like to have a more conformed information on this.

@ Bill,
Thank you for the link in your previous post. That's the information I was reading initially, it is very informative and comprehensive, despite it don't give a practical example of actual implementation referring what Sandisk card exact model can be used.

One crucial point is that the 95LX was not designed to work with flash cards, so it supplies energy to the pcmcia card all the time, even when powered off. This makes sense when RAM cards are used as it was meant to.

[striegel]

I don't remember whether I ever used a flash card with my 95LX'es - but I certainly used RAM cards and one combination card that had both RAM and a modem.

There are still two RAM cards here with my current 95LX - HP's F1003A 512K RAM Card and an ACE DoubleCard 4M. Both were really expensive in their time.

The HP 512K card uses a CR-2025 cell to keep its memory when removed from the palmtop and the ACE takes a CR-2325. By the way, the DoubleCard is called that because it's really a 2 MByte RAM card but achieves around double that capacity using Stacker software.

(12-17-2015 08:19 AM)jebem Wrote:  ...
By the way, did you succeed at any point to install and setup a flash PCMCIA memory card on the 95LX?

From what I have been reading it seems that it should be possible using specific brands and specific drivers, but I would like to have a more conformed information on this.
...
One crucial point is that the 95LX was not designed to work with flash cards, so it supplies energy to the pcmcia card all the time, even when powered off. This makes sense when RAM cards are used as it was meant to.

[jebem]

So this 95LX uses a NEC V20 processor.

I used to install these DIP-40 NEC V20 processors in the clone PC's around the 80's.
NEC claimed faster performance when compared to the original Intel 8088 processor.
Although real life benchmarks were not conclusive.

Today I was digging in my electronics components boxes in the basement and found these chips from that era.

In the picture, top down:
- NEC μPD71055C PIU from 1986.
- NEC μPD70108C aka V20 16-bit CPU from 1986 (clone of Intel 8088)
- Intel 8080A 8-bit CPU from after 1974.




And this beauty from Intel: A BASIC interpreter on a System-On-a-Chip.
I first heard about the 803x/5x development platform when I was in Belgium during the mid 80's, and bought one kit from Intel Brussels, complete with full documentation. Spent a small fortune at the time.

I started with this BASIC chip but the interpreter was slow, so later moved to the 8051 developing on PL/M in order to be able to fulfill the required performance on the projects I was involved in.


In the picture: Intel P8052AH-BASIC Version 1.1 from 1983.