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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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30th Mar 2022, 7:41 pm | #1 |
Octode
Join Date: May 2012
Location: Perth, Scotland
Posts: 1,803
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Perth PET
After several months of no problems, the PET froze today and won't reboot. I once (but only once) got an interesting message at boot about "formula too complex" (see attached photos), but I now consistently get either just the garbage screen at boot, or the garbage screen followed by flashing versions of the other photo attached.
I had already ordered a ROM/RAM board from https://www.thefuturewas8bit.com/ so I hope that'll help me towards the problem. https://www.thefuturewas8bit.com/sho...petromram.html I may be back in a while asking for further help..... Colin. |
30th Mar 2022, 7:53 pm | #2 |
Dekatron
Join Date: Aug 2011
Location: Newcastle, Tyne and Wear, UK.
Posts: 11,553
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Re: Perth PET
Sorry to hear you are having problems again.
I think we should wait until you have the diagnostic tool as it will allow you to rule both the ROMs and the RAM in or out with just a few switch clicks. If it is working enough to let you run either the Slothie or Daver2 test EPROMs there would be no harm in seeing what happens with those. |
30th Mar 2022, 7:54 pm | #3 |
Octode
Join Date: May 2012
Location: Perth, Scotland
Posts: 1,803
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Re: Perth PET
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30th Mar 2022, 7:58 pm | #4 |
Dekatron
Join Date: Aug 2011
Location: Newcastle, Tyne and Wear, UK.
Posts: 11,553
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Re: Perth PET
As mentioned in (edited) post #2, you could try the test EPROMs and see how far they get and what they say.
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30th Mar 2022, 8:18 pm | #5 |
Octode
Join Date: May 2012
Location: Perth, Scotland
Posts: 1,803
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Re: Perth PET
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30th Mar 2022, 8:51 pm | #6 |
Dekatron
Join Date: Aug 2011
Location: Newcastle, Tyne and Wear, UK.
Posts: 11,553
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Re: Perth PET
Slothie's goes in UD9 position but you must use the adaptor it was sent in. It doesn't require any of the other PROMs to be present.
Daver2 goes directly into UD8 position but also requires a working original UD9 in the UD9 position, as the machine boots from UD9. |
30th Mar 2022, 8:59 pm | #7 | |
Octode
Join Date: May 2012
Location: Perth, Scotland
Posts: 1,803
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Re: Perth PET
Quote:
Colin. |
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31st Mar 2022, 7:19 pm | #8 | |
Octode
Join Date: May 2012
Location: Perth, Scotland
Posts: 1,803
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Re: Perth PET
Quote:
Sirius - could you let me know what it would take for them to be recreated please? Thanks. Colin. |
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31st Mar 2022, 8:40 pm | #9 |
Dekatron
Join Date: Aug 2011
Location: Newcastle, Tyne and Wear, UK.
Posts: 11,553
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Re: Perth PET
There was a point some months ago where you offered to send them off to another PET owner who was having problems here, did you maybe do that, or did you at least pack them up with the intention of doing so?
How soon are you expecting the ROM / RAM device to arrive? I believe one of the features of that device is a set of test routines similar to the ones in the two test EPROMs you had - AJ would know as he has one, although he has been worryingly quiet lately. If you expect it in a day or three maybe just wait a little longer. If it will be more like weeks I can make you a Daver2 and that will drop straight in. For the Slothie code I'd have to adapt something again. I don't think I can get them away until early next week at the earliest (real life getting in the way). |
31st Mar 2022, 9:30 pm | #10 |
Octode
Join Date: May 2012
Location: Perth, Scotland
Posts: 1,803
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Re: Perth PET
No worries. I'll chase back in my memory to see if I did send them.
I'm hoping the device should turn up mid next week and we are away Northwards next week anyway. I'll let you know. Thanks. Colin. |
31st Mar 2022, 9:35 pm | #11 |
Nonode
Join Date: May 2004
Location: Halifax, West Yorkshire, UK.
Posts: 2,587
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Re: Perth PET
Still here Sirius. My ROM/RAM board isn't the same as the Tynemouth board Colin has ordered although the two have distinct similaries in terms of functionality. If it helps I am attaching a copy of the User Guide for Colin's board from which you will see that he'll be able to selectively replace areas of ROM for diagnostic purposes.
Alan |
31st Mar 2022, 9:46 pm | #12 |
Octode
Join Date: May 2012
Location: Perth, Scotland
Posts: 1,803
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Re: Perth PET
While I was there, I ordered an SD2PET as well; when I'm back up and running I'll post my views on it in a new thread.
Colin. |
31st Mar 2022, 9:48 pm | #13 |
Dekatron
Join Date: Aug 2011
Location: Newcastle, Tyne and Wear, UK.
Posts: 11,553
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Re: Perth PET
Thanks AJ, very useful (that's why we need you to stick around). I see it does also contain a set of test routines so that should be very helpful when it arrives. Colin will even get to play with BASIC V4 should the mood take him, his is natively BASIC V2.
Edit: All noted Colin. I guess you'll have to fix it now that you've bought an expensive toy for it. I expect that the SD2PET will act in a similar way to a Floppy drive, probably using the same commands and syntax as the original Commodore drive, although hopefully it will be quite a bit faster than the real thing. That would make sense to me, anyway. It will plug into the IEEE port so hopefully the work you did to fix that will now pay off. |
31st Mar 2022, 10:18 pm | #14 |
Nonode
Join Date: May 2004
Location: Halifax, West Yorkshire, UK.
Posts: 2,587
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Re: Perth PET
Just a note of caution about the Tynemouth ROM/RAM board. There have been a few different versions of the board and the User Guide I posted doesn't seem to correspond with the photo of the one Colin's ordered in terms of the number of DIP switches. The Guide may only be directly applicable to an earlier version. Colin will no doubt find out more when his board arrives.
Alan |
9th Apr 2022, 5:48 pm | #15 |
Dekatron
Join Date: Aug 2011
Location: Newcastle, Tyne and Wear, UK.
Posts: 11,553
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Re: Perth PET
Hi Colin, just saw that you have bought yourself a disc drive - I presume for this machine. Does that mean the machine works with your ROM/RAM gadget in it or did it not arrive yet?
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9th Apr 2022, 6:57 pm | #16 | |
Octode
Join Date: May 2012
Location: Perth, Scotland
Posts: 1,803
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Re: Perth PET
Quote:
Colin. |
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9th Apr 2022, 7:03 pm | #17 |
Dekatron
Join Date: Aug 2011
Location: Newcastle, Tyne and Wear, UK.
Posts: 11,553
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Re: Perth PET
Aww, good for you, I do the Kyle to Ullapool section (my favourite bit) nearly every year. We'll look out for you in a few days.
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10th Apr 2022, 7:00 pm | #18 |
Octode
Join Date: May 2012
Location: Perth, Scotland
Posts: 1,803
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Re: Perth PET
OK - back.
With the ROM/RAM plugged in and using the new ROM/RAM on the board, it all works just fine. However, with the RAM swapped back out to the original motherboard RAM, I get the error as described above. If I run the simple test on the Tynemouth board, I get all B for the RAM check. As before, I really want to fix this rather than depend solely on the Tynemouth board. Any good ideas where to start? Ta. Colin. |
10th Apr 2022, 7:33 pm | #19 |
Dekatron
Join Date: Aug 2011
Location: Newcastle, Tyne and Wear, UK.
Posts: 11,553
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Re: Perth PET
Sorry, I think we need to meet somewhere in the middle here as only you have that exact test tool. Can you point us to an online version of the user manual for your version of the RAM/ROM board? I'm not too clear what 'all B' means.
From the sound of it it is saying it doesn't get a sensible response from any of the RAMs but sudden complete failure of all the RAMs is quite unlikely, so it's more likely to be something common to all of the RAM, a missing supply voltage perhaps, or failure of one of the buffers through which all the RAM data passes. I take it you had no luck finding those test EPROMs? |
10th Apr 2022, 8:35 pm | #20 | |
Octode
Join Date: May 2012
Location: Perth, Scotland
Posts: 1,803
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Re: Perth PET
It is per the PDF in an earlier post - page 3:
"The second is a screen showing the result of testing the first 1K of RAM. ‘G’ or ‘g’ indicates a good byte, ‘B’ or ‘b’ indicates a RAM fault. If you get any ‘B’ or ‘b’ characters, you have a RAM fault in at least the first 1K or RAM (lucky you just bought a RAM replacement board eh, just click on switches 1 and 2 and you should get a screen full of ‘G’ or ‘g’)." It's not a very detailed test in my view... And no sadly - having turned over my work room completely, I still haven't found the test EPROMs.... Colin. Quote:
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