Zel's Fleet Blog - BX, Jag XJ-S, Sinclair C5, Mercedes 208D & 230TE, AC Model 70.

[Zelandeth]

Zel - a thought has occurred to me. Are you displaying calculators as well as home computers at the show? If so I could lend you my Sinclair Cambridge programmable with the manual set if you haven't managed to find one yet. If so and you can make lunch next Tuesday, Link here, let me know and I'll bring them along.

Yes I will, but I think I've got things fairly well covered. I'd rather not be risking anyone else's equipment at an event that folks I don't personally know have access too as well.

This afternoon I absolutely had not planned on taking this door apart again.



The driver's window however had other ideas and refused to wind back up again.

I think there's a dirty spot on the motor commutator as it occasionally "skips" while winding, and it managed to stop on exactly that spot. Once I'd stripped the door down far enough to figure out exactly where the motor was and highly technically thump it, it started working again.

Because French. Also "exactly the sort of issue to expect on a car that's not been used regularly in forever."

On the computer side of things, after over an hour of digging around and knocking things over in the loft I eventually found this pair.



As is traditional the Amiga was somewhat cranky on initial startup from being in storage for a while.



After picking it up and dropping it onto the table from a couple of inches a few times however (this has been a ritual dating back the best part of 20 years if the machine hasn't been in regular use!), it woke up and we got to a functioning Workbench.





This drive has always been like this, it's absolutely fine if in regular use, but gets grumpy if stored for more than a couple of months. Nothing critical on there anyway, mostly just been using this to archive stuff and transfer back to my PC recently.

The Atari I'll give a test tomorrow. I've never actually had it hooked up to a display so it may not even work!

This laptop surfaced while I was looking for the other two.





Which turned into an interesting quick experiment.





I do always forget how much worse LCD panels from this era were than the plasma screens they replaced. I'd take a plasma screen over a DSTN LCD any day!

I've never actually used OS/2 before so will need to figure my way around it.

[CitroJim]

Gosh! There's a veritable museum there Zel Long, long time since I've seen OS/2 running!

Have you any machines running CP/M? That was the first Disk OS I cut my teeth on before moving to Unix so has special memories

[Dormouse]

Try this museum then


https://www.bbc.co.uk/news/uk-england-m ... r-64413424


I assume you know about this one Zel.

[Zelandeth]

Gosh! There's a veritable museum there Zel Long, long time since I've seen OS/2 running!

Have you any machines running CP/M? That was the first Disk OS I cut my teeth on before moving to Unix so has special memories

I don't currently have anything running CP/M, though pretty sure there are a couple of machines here which could. The Toshiba T1000 being based around an 8088 I think would make it an ideal candidate for CP/M-86 if I ever get it up and going. Or if I found the Z80 coprocessor card, the Apple II.

In fact, if memory serves there was a version released right at the end of its run for the Amstrad CPC wasn't there?

In theory I think the Amstrad PPC-512 could too, as the NEC V30 processor has an 8080 emulation mode - though how many hoops you have to jump through to actually make that work I've no idea. Just something I remember reading.
--

Business as usual here today, with the madness continuing.



To be honest the testing here isn't so much the ZX81 as the TV it's currently plugged into which we don't reckon had seen power since the mid 90s until today. Unsurprisingly in my experience given its origins aside from the CRT taking a little bit of time initially to wake up again it couldn't have cared less and could just as well have been put away last week.

I did however feel sorting this was necessary!



Don't think I'll need any other televisions at least. The ZX81 is the only system involved which only has an RF output.

[CitroJim]

In fact, if memory serves there was a version released right at the end of its run for the Amstrad CPC wasn't there?

Yes, all the Amstrad CPC and PCW machines would run CP/M Zel and on a CPC6128 was where I really learned it to get to grips with MP/M - the multi-user CP/M we used at work... That was a clever system... MP/M was the supervisory OS with multiple instances of CP/M running in extended memory... A bit like Hyper-V or VMWare but long pre-dating either...

The ZX-81 was where I first learned to program in raw 8080 machine code...

Using a proper compiler, linker and debugger on a later Amstrad CPC was a revelation for writing machine code. I used the old original Microsoft M80 and L80 Compiler and linker... Good software in those days...

Then I taught myself C...

All forgotten now...

[Zelandeth]

In fact, if memory serves there was a version released right at the end of its run for the Amstrad CPC wasn't there?

Yes, all the Amstrad CPC and PCW machines would run CP/M Zel and on a CPC6128 was where I really learned it to get to grips with MP/M - the multi-user CP/M we used at work... That was a clever system... MP/M was the supervisory OS with multiple instances of CP/M running in extended memory... A bit like Hyper-V or VMWare but long pre-dating either...

The ZX-81 was where I first learned to program in raw 8080 machine code...

Using a proper compiler, linker and debugger on a later Amstrad CPC was a revelation for writing machine code. I used the old original Microsoft M80 and L80 Compiler and linker... Good software in those days...

Then I taught myself C...

All forgotten now...

Similarly it was on a Spectrum where I really played around with machine code for the first time.

At college they tried to get us to do the same with a 6502 and I just never got along with that. Can't remember what it was that completely threw me, I think it was something about how the 6502 handled memory addressing.

[CitroJim]

At college they tried to get us to do the same with a 6502 and I just never got along with that. Can't remember what it was that completely threw me, I think it was something about how the 6502 handled memory addressing.

Oh gosh yes 6502 machine code programming was brutal compared to the 8080/Z80... I never got along with it either

[Michel]

At college they tried to get us to do the same with a 6502 and I just never got along with that. Can't remember what it was that completely threw me.

I recall those days when I was at Salford Tech doing microprocessor control and software engineering.
Zero Page addressing?

[Zelandeth]

Well I've just spent another couple of hours faffing about with the sticky door latch on the 25. On the plus side I've figured out why it's being a pain. On the negative side the basic summary is that it's stuffed and I need a new one.

The striker plate itself has a plastic coating on, this has started to peel off and has bunched itself up in the middle of the locking mechanism. Which is assembled in a way that really isn't friendly to the idea of being dismantled. Even if I could get it to bits to fish out the bits of plastic I don't think it will work properly without it as part of the "ramp" used to release the catch is moulded into the plastic rather than the metal. I know this as it was one of the loose bits I was able to fish out of it - opening the door now requires a carefully aimed shoulder bash from inside the car. It's still a git to get to latch too.

Yeah, that's going to be a nice and easy part to find in 2023 I'm sure!

[Michel]

Could you not heat the mechanism up and melt the plastic out of it?

[Dormouse]

Are the rear latches the same, if so, swop them until you find a replacement.

[Zelandeth]

Are the rear latches the same, if so, swop them until you find a replacement.

That's something I'm going to take a look at shortly. I seriously doubt I'm that lucky, but only one way to find out.

Could you not heat the mechanism up and melt the plastic out of it?

Sadly several *structural* parts of the latch mechanism are also plastic! So that's not really an option.

[CitroJim]

3D print new bits perhaps?

[CitroJim]

And can the failing plastic bits be recreated in say, aluminium?

[Zelandeth]

Hmm, so can the front and rear latches be swapped? Let's find out.

Front latch:



Rear latch:



Bolt spacing looked the same, and measuring it showed it to be identical. Had to be worth a closer look. So I set about stripping the front door (again) and making my way into the rear door as well. Getting the lock out of the rear door is a little more fiddly than the front, but wasn't particularly difficult.

Rear on the left, front on the right.







The core components are the same - though some different bits tacked on for handling locking. However I reckoned we could make it work.

Fitting the rear latch in the front (after bending the little lever for the child locks out the way) was pretty easy. The only thing I couldn't easily hook up was the rod from the key barrel. I can live with that, central locking still works from either the passenger door or button on the centre console. In the rear the only thing I couldn't hook up was the lock plunger - again I can live with that as it will still lock/unlock with the central locking.

Ideal? No. However far better than having a driver's door you need to slam with 90% of your strength to close and have to bodyslam to open.

So let's put everything back together.



Uh... didn't I say put back together? Yeah...I did get the rear door fully back together. Then went to close the window. At which point there was a truly comedic "sproing" noise from inside the door and the window lost all interest in moving. So I had to take it all apart. Again. With the window manhandled into a closed position (I'll address the failed winder cable at a later date). Another half hour later I finally had that door back together.



Another 20 or 30 minutes later I had the front buttoned up again too.



I was rather running out of light by that point.



I'm pretty knackered now, and long term do still need to find a replacement lock - at least before the end of July when the MOT tester will want to actually open the offside rear door...but for now it means the car is actually usable, so that is a big step forward.

It looks like a couple of folks on a couple of forums have located decent looking candidates for a replacement - thanks for the suggestions folks, I really appreciate the help.