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chatGPZ
Registered: Dec 2001
Posts: 11503 |
Testers needed: unemulated DMA Delay Artefacts
Steve West has reported some interesting findings on yet unemulated DMA Delay Artefacts, see here
We need to collect more data here. If you are able to open up your C64 so you can report back the ASSY and the VICII type, please take a couple minutes and do the following:
- run the vsp-tester.prg (or vsp-tester-ntsc.prg) from here
- report the ASSY and the exact markings on the VICII
The program will display the detected address, and show green border if that address is known good, or red border if not.
- report the border color, and the address it shows
Interesting are tests on all kind of C64s and Videochips, we need to confirm (or not) how certain values are related to certain videochips.
(For those who care: this could be a working emulator detection for a while)
TIA! |
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Cruzer
Registered: Dec 2001
Posts: 1049 |
Got some more C64s dusted off...
PAL
ASSY No. 250466
MOS 6569R5 3786 S
Green, 38FF
PAL
ASSY No. 250425
VIC chip is in one of those metal boxes, which I don't feel like breaking open, so this test is probably pretty useless.
Green, 38FF
Besides that I got two more C64s that are defective, which reminds me that I should probably get them repaired or sell them to someone who can use them for spare parts. |
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Quiss
Registered: Nov 2016
Posts: 52 |
Assy No. 250469
MOS 8562R2 1987 22
Red border, no address shown: https://photos.app.goo.gl/zUJNoBFfY8jgXsy47
(PAL C64, but 60hz 110V power adapter. Otherwise, machine works fine.) |
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zenda
Registered: Nov 2006
Posts: 22 |
PAL
ASSY 250425
MOS 6569R3
1985
Green, 38FF
PAL
250469 rev. 4
PCB 252311
8565R2
4988 22
Green, 3807 |
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ΛΛdZ
Registered: Jul 2005
Posts: 153 |
assy 250469
8565r2 3592 22
green - 3807
aasy 250425
(VIC was behind metal case :/)
green - 38ff |
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chatGPZ
Registered: Dec 2001
Posts: 11503 |
Thanks ppl! Looks like this is less than stable :(
Some more data might help in any case - please keep it coming :) |
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Martin Piper
Registered: Nov 2007
Posts: 739 |
To try to narrow down electrical pull-up bus issues, with dry hands and after recently grounding yourself, touch various pins and traces on the VIC and the RAMs. Note any visual changes.
To ground yourself briefly touch the metal shielding around the edge of the board, for example. |
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AüMTRöN
Registered: Sep 2003
Posts: 44 |
I ran it several times out of interest as my machine is definetly VSP unstable... hope its not just noise...
assy 250469
vic 8565r2 3090
1. Green - 3807
2. Red - 38C7
3. Red - 38C7
4. Red - 38DF
5. Red - 38C7
6. Green - 38D7
7. Red - 38DF
8. Red - 38C7
9. Red - 38C7
10. Red - 38C7
Run 1 was from cold power up. |
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chatGPZ
Registered: Dec 2001
Posts: 11503 |
Really too bad this is really unstable :( Must be a race condition in the VIC, or something like that. |
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Quiss
Registered: Nov 2016
Posts: 52 |
This happens in the same cycle as the VSP bug, right? |
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chatGPZ
Registered: Dec 2001
Posts: 11503 |
Good question! |
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