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teenix · 07-25-2019, 02:20 PM

Hi all,

Can you believe it, the darn thing fired up and seems stable. It turned out to be a couple of things, one floating processor input, and some code bugs which took hours and many chip flashings to find. One bug was a 2 typed instead of a 0. Funny thing was, that bug has been there for ages and only showed up with the SM chips - weird.

I haven't tested the card reader yet, too tired, is now AM, so look into that tomorrow.

cheers

Tony

**rprosperi** · 07-25-2019, 05:13 PM

(07-25-2019 02:20 PM)teenix Wrote: Hi all,

Can you believe it, the darn thing fired up and seems stable. It turned out to be a couple of things, one floating processor input, and some code bugs which took hours and many chip flashings to find. One bug was a 2 typed instead of a 0. Funny thing was, that bug has been there for ages and only showed up with the SM chips - weird.

I haven't tested the card reader yet, too tired, is now AM, so look into that tomorrow.

cheers

Tony

Great news Tony, nice sleuthing. Bet that weird 2 -> 0 bug working up until now kept you up a while...

pavel nemec cz · 07-26-2019, 07:07 PM

(07-25-2019 02:20 PM)teenix Wrote: Hi all,

Can you believe it, the darn thing fired up and seems stable. It turned out to be a couple of things, one floating processor input, and some code bugs which took hours and many chip flashings to find. One bug was a 2 typed instead of a 0. Funny thing was, that bug has been there for ages and only showed up with the SM chips - weird.

I haven't tested the card reader yet, too tired, is now AM, so look into that tomorrow.

cheers

Tony

Hi Tony,

Just you know more people admire your hard work and all your contributions here.

Thank you
P

teenix · 07-27-2019, 02:16 AM

(07-26-2019 07:07 PM)pavel nemec cz Wrote: Hi Tony,

Just you know more people admire your hard work and all your contributions here.

Thank you
P

Hi Pavel,

Thanks for the encouragement. This project certainly has been a steeplechase, lots of hurdles Smile

cheers

Tony

teenix · (This post was last modified: 07-29-2019 11:16 AM by teenix.)

Hi all,

One more hurdle hopefully crossed.

Most of it appears to be working, however, the card read/write is being cranky so I must have inadvertently changed something while chasing down problems.

Below is the new CPU board as it currently stands.

It looks complicated, but broken down into parts, it becomes simpler. One of the new parts is a small Bluetooth module which means that transferring programs to the on board memory chip, setting options and re-flashing the firmware can be accomplished without opening the calculator or modifying the casing for connectors. Just pair the calculator to a PC and away you go.

More fun tomorrow.

cheers

Tony

teenix · (This post was last modified: 08-24-2019 11:55 PM by teenix.)

Hi all,

Boy this project certainly throws some curve balls. I was midway making some PCB design tweeks when the hard disk made a "clunk" sound and the PC died.

Not surprising since it is a Win95 machine with countless hours of use, but why now - that Murphy guy no doubt. Anyway, that mishap threw a big spanner in the works because it had my only copy of Protel Schematic/PCB designer. I'm hoping it might be a mechanical issue which can be fixed, otherwise it's going to be a long road to recovery.

It will have to wait however, as my boss asked be to get back into the cockpit and I'm at Zanthus in remote West Australia for a bit.

http://www.teenix.org/zanthus.jpg

cheers

Tony

**rprosperi** · 08-25-2019, 01:08 AM

(08-24-2019 11:52 PM)teenix Wrote: I was midway making some PCB design tweeks when the hard disk made a "clunk" sound and the PC died.

When old hard drives die, it's most often due to the heads/platter of course, but more often than you'd think, it's the PCB on the drive that has failed, and if you swap the PCB (it's strictly mechanical and trivial to do for most drives, though a few are just about impossible) the drive may work again. So, look for a used drive of the exact same type on eBay, and swap the boards. It's a strange feeling to see it come back to life.

ijabbott · 08-25-2019, 01:45 PM

(08-25-2019 01:08 AM)rprosperi Wrote:
(08-24-2019 11:52 PM)teenix Wrote: I was midway making some PCB design tweeks when the hard disk made a "clunk" sound and the PC died.

When old hard drives die, it's most often due to the heads/platter of course, but more often than you'd think, it's the PCB on the drive that has failed, and if you swap the PCB (it's strictly mechanical and trivial to do for most drives, though a few are just about impossible) the drive may work again. So, look for a used drive of the exact same type on eBay, and swap the boards. It's a strange feeling to see it come back to life.

Of course, if you attempt to do that and fail (which is highly likely), most data recovery companies won't touch it with a barge pole!

**rprosperi** · 08-25-2019, 02:10 PM

(08-25-2019 01:45 PM)ijabbott Wrote:
(08-25-2019 01:08 AM)rprosperi Wrote: When old hard drives die, it's most often due to the heads/platter of course, but more often than you'd think, it's the PCB on the drive that has failed, and if you swap the PCB (it's strictly mechanical and trivial to do for most drives, though a few are just about impossible) the drive may work again. So, look for a used drive of the exact same type on eBay, and swap the boards. It's a strange feeling to see it come back to life.

Of course, if you attempt to do that and fail (which is highly likely), most data recovery companies won't touch it with a barge pole!

True enough, but I assume anyone willing to pay those prices for what would obviously then be valuable data, would not attempt options like suggested above, that is strictly for DIY-ers. I only mention it as most folks are not aware of this option and end up tossing out drives and data than can be recovered relatively cheaply.

Harald · (This post was last modified: 08-25-2019 05:08 PM by Harald.)

(08-24-2019 11:52 PM)teenix Wrote: Anyway, that mishap threw a big spanner in the works because it had my only copy of Protel Schematic/PCB designer. I'm hoping it might be a mechanical issue which can be fixed, otherwise it's going to be a long road to recovery.

cheers

Tony

So what exactly is lost now? Just the latest modifications to the PCB? Do you have a backup of an earlier version? Is the firmware still there, or is that on the same hard drive?

Is your main issue that you now don't have Protel? I could try and go through an old pile of CDs and see if I have a Protel CD. Which version do you need?

Cheers,
Harald

Thomas Okken · 08-25-2019, 07:41 PM

I'm going to be "that guy" and point out that the easiest and cheapest option is to make regular backups. One of the things I like about Macs is how brain-dead easy Time Machine makes this. I haven't had disk drives fail on me yet, but those backups came in quite handy when I upgraded the SSDs in my laptops, and of course being able to recover mistakenly deleted files is nice, too.

ijabbott · 08-25-2019, 09:56 PM

(08-25-2019 02:10 PM)rprosperi Wrote:
(08-25-2019 01:45 PM)ijabbott Wrote: Of course, if you attempt to do that and fail (which is highly likely), most data recovery companies won't touch it with a barge pole!

True enough, but I assume anyone willing to pay those prices for what would obviously then be valuable data, would not attempt options like suggested above, that is strictly for DIY-ers. I only mention it as most folks are not aware of this option and end up tossing out drives and data than can be recovered relatively cheaply.

Well I wouldn't attempt it on any modern drive either. And by "modern" I mean about 2000 onwards. That's mainly because there is non-volatile memory chip on the PCB that is tied to the drive, containing the "adaptive data" for the drive. So you would need to transfer that chip from the old PCB to the donor.

teenix · 08-26-2019, 12:20 AM

(08-25-2019 03:04 PM)Harald Wrote: So what exactly is lost now? Just the latest modifications to the PCB? Do you have a backup of an earlier version? Is the firmware still there, or is that on the same hard drive?

Is your main issue that you now don't have Protel? I could try and go through an old pile of CDs and see if I have a Protel CD. Which version do you need?

Cheers,
Harald

Hi Harald,

I still have source code files, they are backed up daily every time changes are made.

I was modifying the PCB because I figured out a way of driving the project with one processor instead of two. Updating the HP67 LED display is a processor intensive task, but I managed to get around it. Not sure about the HP65 though as it is more intensive.

I was using Protel PCB 2.8 and associated schematic which I have had for years. It does everything I need, is fast, easy to use and the files are still accepted by PCB makers. I think I still have the original floppies, but now no PC for them. I tried the online community based Altium, but is very slooooow to use and will be time intensive to recreate the project.

I have almost the latest project design files backed up on a separate machine.

When I get home I will open up the drive and see what's what. I was thinking of creating a partition on my laptop drive and run win95 on it. From webbing around, I believe it can be done and I think my original CD is somewhere in a box. There is also a win95 app on the web that might work.

cheers

Tony

Thomas Okken · 08-26-2019, 01:11 AM

(08-26-2019 12:20 AM)teenix Wrote: When I get home I will open up the drive and see what's what. I was thinking of creating a partition on my laptop drive and run win95 on it. From webbing around, I believe it can be done and I think my original CD is somewhere in a box. There is also a win95 app on the web that might work.

If you specifically need Windows 95, running it on a modern PC is probably going to be problematic, but you should be able to do it in VirtualBox -- see here, for instance. (That "win95 app" you mentioned sounds like a preconfigured VM, could be a good option as well.)

Paul Dale · 08-26-2019, 10:30 PM

(08-25-2019 01:08 AM)rprosperi Wrote: So, look for a used drive of the exact same type on eBay, and swap the boards. It's a strange feeling to see it come back to life.

Exact down to the month code on the PCB. These things change very often.

Pauli

**rprosperi** · 08-26-2019, 11:40 PM

(08-25-2019 09:56 PM)ijabbott Wrote: Well I wouldn't attempt it on any modern drive either. And by "modern" I mean about 2000 onwards. That's mainly because there is non-volatile memory chip on the PCB that is tied to the drive, containing the "adaptive data" for the drive. So you would need to transfer that chip from the old PCB to the donor.

As noted, if the data is critical and you're willing to pay for professional data recovery, that is the way to go. But if not, this is likely your only option, so even if not perfect, it's better to risk this than just toss it out. For reasons like the adaptive data and others, you should not plan to merrily continue using the repaired drive, but it may give you long enough life to recover the data.

When I did this on vintage drives (where system may need the same drive type to work), I would buy 2 of the same drives, use one for the PCB donor and the other to copy data to once the original is running.

I've successfully repaired about a half-dozen drives this way, it does work.

(08-26-2019 10:30 PM)Paul Dale Wrote:
(08-25-2019 01:08 AM)rprosperi Wrote: So, look for a used drive of the exact same type on eBay, and swap the boards. It's a strange feeling to see it come back to life.

Exact down to the month code on the PCB. These things change very often.

Pauli

Good advice, the closer the mfg. date the more likely it is really the same. Oddly though, I've even seen some boards with visually different chip/component layouts work as replacements.

Harald · 08-28-2019, 08:15 AM

(08-26-2019 12:20 AM)teenix Wrote:
(08-25-2019 03:04 PM)Harald Wrote: So what exactly is lost now? Just the latest modifications to the PCB? Do you have a backup of an earlier version? Is the firmware still there, or is that on the same hard drive?

Is your main issue that you now don't have Protel? I could try and go through an old pile of CDs and see if I have a Protel CD. Which version do you need?

Cheers,
Harald

Hi Harald,

I still have source code files, they are backed up daily every time changes are made.

I was modifying the PCB because I figured out a way of driving the project with one processor instead of two. Updating the HP67 LED display is a processor intensive task, but I managed to get around it. Not sure about the HP65 though as it is more intensive.

I was using Protel PCB 2.8 and associated schematic which I have had for years. It does everything I need, is fast, easy to use and the files are still accepted by PCB makers. I think I still have the original floppies, but now no PC for them. I tried the online community based Altium, but is very slooooow to use and will be time intensive to recreate the project.

I have almost the latest project design files backed up on a separate machine.

When I get home I will open up the drive and see what's what. I was thinking of creating a partition on my laptop drive and run win95 on it. From webbing around, I believe it can be done and I think my original CD is somewhere in a box. There is also a win95 app on the web that might work.

cheers

Tony

So far I have not managed to locate any Protel CDs. I will ask a friend if he has one.

teenix · 08-28-2019, 09:30 AM

Thanks Harald, I appreciate the effort.

cheers

Tony

(08-28-2019 08:15 AM)Harald Wrote: So far I have not managed to locate any Protel CDs. I will ask a friend if he has one.

ijabbott · 08-28-2019, 11:16 PM

(08-28-2019 08:15 AM)Harald Wrote:
(08-26-2019 12:20 AM)teenix Wrote: I was using Protel PCB 2.8 and associated schematic which I have had for years. It does everything I need, is fast, easy to use and the files are still accepted by PCB makers. I think I still have the original floppies, but now no PC for them. I tried the online community based Altium, but is very slooooow to use and will be time intensive to recreate the project.

So far I have not managed to locate any Protel CDs. I will ask a friend if he has one.

Protel 2.8 (a.k.a. Protel Advanced PCB) seems to be easy to obtain by downloading it from various places (just Google it). I'm not sure about the legality of the downloads, but if you already have a license it should be OK.

teenix · 09-25-2019, 05:42 AM

Hi all,

I just returned home from flying in remote West Australia and I pulled the misbehaving hard drive out of the old PC. I couldn't open it because I don't have a Torx screwdriver available, but the PCB seemed clean and no nasties. I thought why not and I gave it a few light taps and plugged it back in.

"Murphy" must be on holidays today as the silly thing worked. I guess maybe a stuck head due to old age causing the clunking sounds. Anyway I quickly got the project schematics data off it and now with some generous help from Harald and a friend of his, the design can continue.

Amazing :-)

cheers

Tony