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Post by miner2049er on Jun 16, 2009 11:45:43 GMT -5
Exploring a long forgotten cupboard at work and I've found a boxed ZX81 with leads and a seperate box with a ZX printer and a RAM expansion pack.
Taking them home to test them later.
There is another old computer of some description in there but we can't see it properly yet. It is rumoured to be either a Commodore Pet or a BBC of some description.
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Post by David Murray on Jun 16, 2009 16:18:02 GMT -5
There is another old computer of some description in there but we can't see it properly yet. It is rumoured to be either a Commodore Pet or a BBC of some description. Somehow, I'm having a hard time imaging a PET inside a cupboard.. hiding, no less. How big is this cupboard?
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Post by retrobits on Jun 16, 2009 16:23:55 GMT -5
This is the kind of thing retrocomputer lovers dream about. It was at work that a friend brought in the PET 2001 and gave it to me as a gift. I don't expect to find any retrocomputers lingering in cabinets (although that would be awesome).
- Earl
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Post by miner2049er on Jun 16, 2009 17:02:37 GMT -5
How big is this cupboard? Haha! Big, it is a space under a stairwell so it goes back quite a way. Anyway, testing has shown the system to be dead, but I took it apart and there is a chip on the circuit board that seems physically damaged. A buddy of mine has told me that it is a cheap, common part like this www.parts-express.com/pe/showdetl.cfm?partnumber=7805 so I will look to replace it at some point soon and try again.
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dilbert
Full Member
Registered Linux User #306113
Posts: 223
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Post by dilbert on Jun 17, 2009 12:12:04 GMT -5
How big is this cupboard? Haha! Big, it is a space under a stairwell so it goes back quite a way. Anyway, testing has shown the system to be dead, but I took it apart and there is a chip on the circuit board that seems physically damaged. A buddy of mine has told me that it is a cheap, common part like this www.parts-express.com/pe/showdetl.cfm?partnumber=7805 so I will look to replace it at some point soon and try again. ;D ;D yes simple - unsolder the three pins - you have to undo the heat sink(one nut and bolt.) replace with heatsink grease. The 7805 is the voltage regulator -in 5 volts- it dropped the 9 volts coming in from the wall wart. ( they needed the current but wasted the 4 volts(heat)..
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Post by miner2049er on Jun 17, 2009 12:23:56 GMT -5
;D ;D yes simple - unsolder the three pins - you have to undo the heat sink(one nut and bolt.) replace with heatsink grease. The 7805 is the voltage regulator -in 5 volts- it dropped the 9 volts coming in from the wall wart. ( they needed the current but wasted the 4 volts(heat).. Yeah, that made me laugh when I saw it. A heatsink on a system like this.
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Post by miner2049er on Jun 18, 2009 16:00:16 GMT -5
I got to the other computer today and had a quick look in semi darkness.
It is a Commodore machine and looks like a PET without the tape drive.
Sneaking it out to test may be tricky but I will rise to the challenge.
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Post by thurstan on Jun 20, 2009 3:53:02 GMT -5
What kind of company do you work for? cant imagine any company using a zx81 back in the day!
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Post by miner2049er on Jun 20, 2009 6:08:07 GMT -5
What kind of company do you work for? cant imagine any company using a zx81 back in the day! A High School.
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Post by miner2049er on Jun 20, 2009 6:08:56 GMT -5
Oh, and I now have 2x 7805 chips so I hope to find time to fit one later and try it out again.
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Post by miner2049er on Jun 23, 2009 3:19:16 GMT -5
The big hulk of a computer hiding at the back is indeed a Commodore PET. It is the 4032 model.
I have it powered up and running with the magical green text on screen but the keyboard is not very responsive, someitmes a key will work and sometmes it won't.
Time to hit Google and see if this is a common fault I can fix by hitting it.
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dilbert
Full Member
Registered Linux User #306113
Posts: 223
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Post by dilbert on Jun 23, 2009 12:36:08 GMT -5
The big hulk of a computer hiding at the back is indeed a Commodore PET. It is the 4032 model. I have it powered up and running with the magical green text on screen but the keyboard is not very responsive, someitmes a key will work and sometmes it won't. Time to hit Google and see if this is a common fault I can fix by hitting it. how about some help? oldcomputers.net/pet4032.html predated by the original 2001 PET oldcomputers.net/pet2001.html
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Post by retrobits on Jun 23, 2009 20:43:30 GMT -5
When I received my PET 2001 it had been sitting in a garage for a long time. And, it was previously used by a school district. The keyboard was pretty stiff at first, and some keys were unreliable. Through some typing and continual taps on the stubborn keys, it loosened up and now types pretty well. Might just take some re-breaking in.
- Earl
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Post by miner2049er on Jun 24, 2009 2:40:19 GMT -5
The keyboard was pretty stiff at first, and some keys were unreliable. Through some typing and continual taps on the stubborn keys, it loosened up and now types pretty well. Might just take some re-breaking in. - Earl Yeah, it has been in a cupboard for donkey's years so I will strip it I think and give it a once over then try again. A couple of keys improved with a can of compressed air blowing the crud out so there is hope for it I think.
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Post by miner2049er on Jun 25, 2009 16:29:01 GMT -5
Well, the ZX81 is dead. I fitted a new 7805 but still nothing happens. officially dead as far as I'm concerned.
The PET keyboard I completely stripped down and reseated everything and it now works perfectly apart from the CAPS Lock key which sticks down.
It is sticking due to a bad solder job that has been done on it before and the plastic has become a little out of shape, so I am slowly trying to make it run smooth again and hopefully get it back to normal.
Question is, what do I do with them both?
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