Commodore PET 8032

[SiriusHardware]

I have some of the black conductive rubber paint too (if that's the sort you have) and it works well on most rubber pill type keypads but the Pana one I'm talking about is suffering from a secondary problem of 'rubber ooze' where a mysterious oil leaches out of the keypad mat - this phenomenon was discussed recently in another (non computer) thread so I won't go into detail here, but the 'ooze' essentially just lifts off any kind of conductive paint. I'm going to have to try to bond these conductive pads to the original mat some other way, but that is outside the scope of what we are discussing here.

[ScottishColin]

Quick update. Keyboard back in place and all keys working fine after the paper rubbing routine

Cassette port 1 works fine and I loaded the IEEE Test code I have saved and that reported no errors.

Attached my SD2PET to the IEEE port and the cassette port for power and that worked first time.

Cassette port 2 does not provide power to the datasette but I haven't looked at that at all yet, nor have I tested the User Port.

Progress though.

I'll finish all that lot off then I'm going to need some monitor help:

1) the display brightness dims over time
2) I can't get the picture square on the screen (off the left hand side)

But let me sort out the PET motherboard ports and then we can go to the market motor.

Colin.

[ortek_service]

Originally Posted by ScottishColin

>>
>>

I'll finish all that lot off then I'm going to need some monitor help:

1) the display brightness dims over time
2) I can't get the picture square on the screen (off the left hand side)

But let me sort out the PET motherboard ports and then we can go to the market motor.

Colin.

With reference to the monitor problems, whilst you are working in the PET then it might be worth doing a quick visual check for:

1. Any Electrolytic capacitors with 'dome' bulged tops, as can often find ones (on power-rails at least) that have dried-up a bit and have started to vent with increased temperature / ripple due to ESR increasing.
As failing Electrolytics are often the cause of time / temperature varying faults - Although with dried-up Electrolytics, the faults are usually worse when cold and get a bit better once warmed-up. So would normally expect brightness to increase rather than decrease (unless it is over-bright initially).
Otherwise, it may be a case of measuring the monitor's various supply rails, when cold and once warmed-up.

2. Any missing / knocked out of position permanent small bar-magnets around the CRT deflection-coils yoke assembly - which mono-CRT's often had two of these, one either side (held on thin strips of metal, to allow adjustment by rotating / moving etc)

[ScottishColin]

Nothing obvious in terms of bulging caps that I can see.

I also attach a couple of photos showing the rear of the monitor; if those square components are magnets, there's three of them not two.

I attach a photo showing every character space taken up and you can see it's on the left hand side of the screen - how do I move that to the right please?

As a reminder, the Monitor PCB is here:

http://www.zimmers.net/anonftp/pub/c...32/8032035.gif

and the schematic is here with the Vertical and Horizontal components documented.

http://www.zimmers.net/anonftp/pub/c...32/8032034.gif

Colin.

[buggies]

I say rotate but mean slightly jiggle the two disks relative to each other - moves raster in all directions.

[ScottishColin]

Thank you - that's solved that one. The last placement problem is that I'd like to move the image up as it's not centered vertically.

I don't seem to be able to do this with the disks; do I need to do something on the PCB?

Thanks very much.

Colin.

Originally Posted by buggies

I say rotate but mean slightly jiggle the two
disks relative to each other - moves raster in all directions.

[buggies]

Hi Colin,
Those magnets should be able to move the picture vertically as well - but (for me) it was always a matter of trial and error as to what happened rotating both together or separately.

[ScottishColin]

Thank you. After some judicious twiddling, it's centred horizontally and vertically now.

I need to look at the monitor PCB now to try to work out what's going on with the intermittent brightness changes, test the User Port and repaint the case.

Nearly there.

Colin.

Originally Posted by buggies

Hi Colin,
Those magnets should be able to move the picture vertically as well - but (for me) it was always a matter of trial and error as to what happened rotating both together or separately.

[SiriusHardware]

Is the brightness intermittent or does it consistently start off bright and then get dimmer over time, as you seemed to suggest earlier?

[ortek_service]

I presume there was originally some Ev0-stick / Hot-melt type glue on these magnets, to stop them moving when being transported, that had failed? - As maybe can't rely on these just being a tight-fit on the peg.
So may want to apply something similar, in case it needs to be transported again, to prevent need to re-adjust.
May find silicone-sealant is also suitable, but need to keep the acetic-acid producing standard type away from any copper etc. and the 'RTV' for Electronics is rather expensive (Typically >20x the cost!).

Originally Posted by ScottishColin

Thank you. After some judicious twiddling, it's centred horizontally and vertically now.

I need to look at the monitor PCB now to try to work out what's going on with the intermittent brightness changes, test the User Port and repaint the case.

Nearly there.

Colin.

[ScottishColin]

Apologies for the dekay.

We have a hot glue gun here for other hobbies - I'll experiment with that as you suggest.

Colin.

Originally Posted by ortek_service

I presume there was originally some Ev0-stick / Hot-melt type glue on these magnets, to stop them moving when being transported, that had failed? - As maybe can't rely on these just being a tight-fit on the peg.
So may want to apply something similar, in case it needs to be transported again, to prevent need to re-adjust.
May find silicone-sealant is also suitable, but need to keep the acetic-acid producing standard type away from any copper etc. and the 'RTV' for Electronics is rather expensive (Typically >20x the cost!).

[ScottishColin]

Further update - case rubbed down and rust gone, now I need a non-raining non-work day when I can do some spraying. I have a different colour this time to the 3016 (which I think is too white). I'll let you see it when it's all back together.

I've also asked whether there are any more of these available as I thought it might be interesting to get some 80 column software like Visicalc or Wordpro running on it.

http://primrosebank.net/computers/pe...multi_roms.htm

Colin.

[ortek_service]

Originally Posted by ScottishColin

Further update - case rubbed down and rust gone, now I need a non-raining non-work day when I can do some spraying. I have a different colour this time to the 3016 (which I think is too white). I'll let you see it when it's all back together.
>>
>>
Colin.

Yes, I'm not sure they were ever that white a colour
- Although they might have gone a bit 'Yellow' over the years, for that "more-vintage" look.

Originally Posted by ScottishColin

>>
>>
I've also asked whether there are any more of these available as I thought it might be interesting to get some 80 column software like Visicalc or Wordpro running on it.

http://primrosebank.net/computers/pe...multi_roms.htm

Colin.

Well he does at least say "I have a very limited quantity of the boards but will order more should they be required.".
So it seems he was prepared to get more stock, when required
- I imagine he does what ChrisOddy (with his Acorn / SoC boards / some components) etc does, and only buys a few at a time if still available , so as to avoid potential risk of being stuck with lots of unsold stock for years.
But probably difficult to anticipate demand for retro computer hardware.

[ScottishColin]

The supplier has been in contact and they're looking them out now. As I get them I'll put an update here as they look interesting/useful devices.

Colin.

Originally Posted by ortek_service

Well he does at least say "I have a very limited quantity of the boards but will order more should they be required.".
So it seems he was prepared to get more stock, when required
- I imagine he does what ChrisOddy (with his Acorn / SoC boards / some components) etc does, and only buys a few at a time if still available , so as to avoid potential risk of being stuck with lots of unsold stock for years.
But probably difficult to anticipate demand for retro computer hardware.

[ScottishColin]

I thought you might like to see the final refurbished PET along with the working printer and 3040 that has been brought back to life with your help.

Original picture attached so you can see what it was like when I got it.

Colin.

[SiriusHardware]

Fantastic, what a difference. And they work too! They've certainly found the right owner. Just the typewriter-printer to try to get working now.

Has the original owner dropped by to see how they are doing, do you know? I'm sure he would be pleased to see them working so well.

[ScottishColin]

Thank you.

As it happens, I have found the original owner of the PET and the typewriter/printer. It wasn't tricky - there is a sticker on the back of the PET chassis with their name and address (Cheshire), and the same postcode was put on the typewriter/printer with one of those security marker pens.

It's also possible that the dot matrix printer and disk were theirs too but I cannot be sure. I have managed to contact him through a bit of Google sleuthing and have sent a couple of emails to him with updates/progress.

I actually bought them from a chap who lives in Shropshire who bought them from the original owner and have been keeping him in touch too. He very much would like to see the typewriter/printer working so I need to apply myself to that now.

He is a retired TV engineer and has I am told a significant collection of old computers - I have encouraged him to join us here, but I'm not aware that he has.

Colin.

Originally Posted by SiriusHardware

Fantastic, what a difference. And they work too! They've certainly found the right owner. Just the typewriter-printer to try to get working now.

Has the original owner dropped by to see how they are doing, do you know? I'm sure he would be pleased to see them working so well.

[SiriusHardware]

So you effectively now have the whole history of ownership from new, at least for the PET and typeprinter? That's fairly unusual, and all adds up to a nice provenance to go with the machine(s).