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Vintage Computers Any vintage computer systems, calculators, video games etc., but with an emphasis on 1980s and earlier equipment.

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Old 14th Apr 2021, 6:20 pm   #1641
ajgriff
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Default Re: Non-working Commodore PET 3016

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Originally Posted by Slothie View Post
From my memory the paint on my 2001 was a sort of silk white with little lumps in it (similar to the old "eggshell" paint). It wasn't particularly "gloss", more like that textured finish you get on plastic casings but less well defined.
Reminiscent of spray painting defects that you might expect from a manufacturer of budget office furniture! I think it would be a mistake to overestimate the quality of the finish. For example I could see no evidence to suggest that a primer was used.

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Old 14th Apr 2021, 6:26 pm   #1642
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Default Re: Non-working Commodore PET 3016

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I'm not really up for the expense of getting matched paint at an automotive supplier.
I think its still worth going to an automotive paint factor even if you donít bother to get a matched paint.

They used to fill spray cans for touch up, cellulose paint, that were significantly better for spraying than the cans you get in halfords and other similar places. Much better coverage and propellant and not much more expensive. Iím talking about 25+ years ago so regulations on what they can supply may have changed.
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Old 14th Apr 2021, 6:52 pm   #1643
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Default Re: Non-working Commodore PET 3016

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Quote:
Originally Posted by Slothie View Post
From my memory the paint on my 2001 was a sort of silk white with little lumps in it (similar to the old "eggshell" paint). It wasn't particularly "gloss", more like that textured finish you get on plastic casings but less well defined.
Reminiscent of spray painting defects that you might expect from a manufacturer of budget office furniture! I think it would be a mistake to overestimate the quality of the finish. For example I could see no evidence to suggest that a primer was used.

Alan
Yes, I think the only nod to quality was that the paint outside was fairly thick. Plenty of semi-visible metal on the inside!
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Old 14th Apr 2021, 7:08 pm   #1644
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Default Re: Non-working Commodore PET 3016

Colin didn't say how the unit was marked with the postcode (Of Kendal College, Cumbria). Engraved? Stencilled? It would be a pity if that historic detail was lost. If it can't be preserved on the outside then maybe it could be re-inscribed or painted on the inside.

I'm wondering now if the machine was disposed of by the college in an already electronically ruinous state - the educational environment is a notoriously tough one for anything to have to survive. If so, Colin may be the first person to see it working since it last worked there. It's just a shame that the interim owner didn't keep it in a drier place.
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Old 14th Apr 2021, 7:19 pm   #1645
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Default Re: Non-working Commodore PET 3016

It's a bit, er, maunual. Like you, I don't want to lose it either. I'll have to find away to tidy the case up but leave that bit.

https://drive.google.com/file/d/1QuC...ew?usp=sharing

Colin.


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Colin didn't say how the unit was marked with the postcode (Of Kendal College, Cumbria). Engraved? Stencilled? It would be a pity if that historic detail was lost. If it can't be preserved on the outside then maybe it could be re-inscribed or painted on the inside.

I'm wondering now if the machine was disposed of by the college in an already electronically ruinous state - the educational environment is a notoriously tough one for anything to have to survive. If so, Colin may be the first person to see it working since it last worked there. It's just a shame that the interim owner didn't keep it in a drier place.
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Old 14th Apr 2021, 7:29 pm   #1646
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Default Re: Non-working Commodore PET 3016

Mm, now I see it I think it will be difficult to eradicate the rust and still keep the engraved postcode where it is. The priority is probably to neutralise the rust otherwise it may start coming through any paint or coating you care to put on it.

I think it would be OK just to repaint it on the inside somewhere, as long as that detail stays with the machine.
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Old 14th Apr 2021, 7:33 pm   #1647
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Default Re: Non-working Commodore PET 3016

The engraving should survive I would think it is probably quite deep - just don't fix it - you can always manually adjust the engraving after and lacquer it to stop it rusting?
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Old 14th Apr 2021, 7:35 pm   #1648
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Default Re: Non-working Commodore PET 3016

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It's a bit, er, maunual.
I think the postcode will always look like a rather ugly scar. Why not replicate it on a label discreetly stuck to the serial number plate?

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Originally Posted by Mark1960 View Post
I think its still worth going to an automotive paint factor even if you donít bother to get a matched paint.

They used to fill spray cans for touch up, cellulose paint, that were significantly better for spraying than the cans you get in halfords and other similar places. Much better coverage and propellant and not much more expensive. Iím talking about 25+ years ago so regulations on what they can supply may have changed.
Modern (acrylic) proprietary aerosol sprays really are very good.

Alan
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Old 14th Apr 2021, 7:41 pm   #1649
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Default Re: Non-working Commodore PET 3016

I've just been looking at Kendal College's website, they still have a computing department there. If they have an in-house magazine the survival and resurrection of this machine which obviously came from there originally would make quite an interesting story for them. We have to hope, of course, that it was officially disposed of / acquired legitimately all those years ago.
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Old 14th Apr 2021, 7:46 pm   #1650
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Default Re: Non-working Commodore PET 3016

Funnily enough, that's next on my list - to contact them to let them know.

I'm playing Chess right now. it's great to be able to play some games that bring back memories.

Colin.


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Originally Posted by SiriusHardware View Post
I've just been looking at Kendal College's website, they still have a computing department there. If they have an in-house magazine the survival and resurrection of this machine which obviously came from there originally would make quite an interesting story for them. We have to hope, of course, that it was officially disposed of / acquired legitimately all those years ago.
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Old 14th Apr 2021, 7:47 pm   #1651
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Default Re: Non-working Commodore PET 3016

Does anyone know how to get the labels off so I can paint the PET - I think my masking skills won't be up to it, and there's always the possibility that there is rust under the labels that needs got rid of too.

Colin.
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Old 14th Apr 2021, 7:58 pm   #1652
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Default Re: Non-working Commodore PET 3016

There's isn't a chess player in the world, human or otherwise, that can't trounce me at chess so it's not exactly my favourite game.

My best guess would be that the labels / decals will come off more easily when the metalwork is quite warm. Not having seen one close up I assume the main 'PET' logo is printed on a bit of brushed aluminium which is stickied onto the casing, probably in a slight hollow just the right size and shape. This is definitely not my area, though.
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Old 14th Apr 2021, 8:06 pm   #1653
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Default Re: Non-working Commodore PET 3016

The label is vinyl and glued on - not the original aluminium type.

On the IEEE subject, is the code on page 184 of this PDF worth typing in to try?

http://www.1000bit.it/support/manual...EEE488_Bus.pdf

Colin.
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Old 14th Apr 2021, 8:10 pm   #1654
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Default Re: Non-working Commodore PET 3016

My PET had a vinyl-like sticker with a metallic foil backing that would be hard to remove without tearing as its quite thin. Perhaps some kind of solvent and a q-tip and a huge amount of care might do it...
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Old 14th Apr 2021, 8:10 pm   #1655
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Default Re: Non-working Commodore PET 3016

Here's the label.

https://drive.google.com/file/d/1MxY...ew?usp=sharing

Colin.
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Old 14th Apr 2021, 8:14 pm   #1656
Slothie
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Default Re: Non-working Commodore PET 3016

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Originally Posted by ScottishColin View Post
The label is vinyl and glued on - not the original aluminium type.

On the IEEE subject, is the code on page 184 of this PDF worth typing in to try?

http://www.1000bit.it/support/manual...EEE488_Bus.pdf

Colin.
I used to have that book! I'd forgotten it had a test program. Yes, it would be a great idea to test with that. it will tell you if the IEEE bus drivers are working, and they have been known to fail. It will also check the 6520 that they are connected to.
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Old 14th Apr 2021, 8:19 pm   #1657
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Default Re: Non-working Commodore PET 3016

I think you'll ruin the labels if you try removing them. I doubt if rust has developed underneath the labels unless they're showing signs of peeling. Careful masking is the only answer in my view. Definitely worth buying some modellers masking tape. Just a reminder of what can be achieved:

https://www.vintage-radio.net/forum/...&postcount=185

The modellers tape is yellow in this example.

Alan
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Old 14th Apr 2021, 8:23 pm   #1658
SiriusHardware
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Default Re: Non-working Commodore PET 3016

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Originally Posted by ScottishColin View Post
On the IEEE subject, is the code on page 184 of this PDF worth typing in to try?
Sorry, I didn't notice that you had tried the super simple test I suggested earlier (The same test is buried in the start of that longer program, which is probably worth typing in and saving since you appear to have a working tape setup).

Anyway, the second result should be 255 (same as the number you wrote out in the second instance).

When you write out 255 (decimal) you are sending all 1s (11111111) to the output latches and when you PEEK the port you should see the same bit states coming back, but instead you are seeing 126 which is 01111110, suggesting a possible fault with bits 0 and 7 of the port.

Try that program and see what it reports. If it agrees there is a problem we'll drill down and find out whether the problem is with output to the port or readback from the port.

If you

Code:
POKE 59426,0
and then measure the voltages on the IEEE port 1,2,3,4,A,B,C,D connections all those lines should be 0V / logic 0.

If you then

Code:
POKE 59426,255
and measure the voltages on pins 1,2,3,4,A,B,C,D again, all those lines should now be at logic 1 (~3V or greater).

Last edited by SiriusHardware; 14th Apr 2021 at 8:28 pm.
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Old 14th Apr 2021, 9:08 pm   #1659
ScottishColin
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Default Re: Non-working Commodore PET 3016

I'll take your advice - thanks. Going to be a couple of days before I start on this I think. I need to get the rust off first and then rub it down.

Colin.


Quote:
Originally Posted by ajgriff View Post
I think you'll ruin the labels if you try removing them. I doubt if rust has developed underneath the labels unless they're showing signs of peeling. Careful masking is the only answer in my view. Definitely worth buying some modellers masking tape. Just a reminder of what can be achieved:

https://www.vintage-radio.net/forum/...&postcount=185

The modellers tape is yellow in this example.

Alan
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Old 14th Apr 2021, 9:31 pm   #1660
ScottishColin
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Default Re: Non-working Commodore PET 3016

OK - typed it in and run it (it makes me miss cut&paste...).

As suggested, it reports that the bad GPIB bits are 7 and 0.

Colin.


Quote:
Originally Posted by SiriusHardware View Post
Quote:
Originally Posted by ScottishColin View Post
On the IEEE subject, is the code on page 184 of this PDF worth typing in to try?
Sorry, I didn't notice that you had tried the super simple test I suggested earlier (The same test is buried in the start of that longer program, which is probably worth typing in and saving since you appear to have a working tape setup).

Anyway, the second result should be 255 (same as the number you wrote out in the second instance).

When you write out 255 (decimal) you are sending all 1s (11111111) to the output latches and when you PEEK the port you should see the same bit states coming back, but instead you are seeing 126 which is 01111110, suggesting a possible fault with bits 0 and 7 of the port.

Try that program and see what it reports. If it agrees there is a problem we'll drill down and find out whether the problem is with output to the port or readback from the port.

If you

Code:
POKE 59426,0
and then measure the voltages on the IEEE port 1,2,3,4,A,B,C,D connections all those lines should be 0V / logic 0.

If you then

Code:
POKE 59426,255
and measure the voltages on pins 1,2,3,4,A,B,C,D again, all those lines should now be at logic 1 (~3V or greater).
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