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04 September 2013, 15:12
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#21 |
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ex. demoscener "Bigmama"
Join Date: Jun 2012
Location: Fyn / Denmark
Posts: 1,624
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are you currently running at 25MHz? From the photo, it looks like you still have CLK90 modded..
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04 September 2013, 16:20
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#22 |
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Registered User
Join Date: Apr 2012
Location: Canada
Age: 44
Posts: 910
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Yes, this is still at 25 MHz, I left the clock 90 mod, since it according to general reports, it should not interfere with card function regardless of the speed.
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05 September 2013, 01:40
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#23 |
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Moderator
Join Date: Dec 2010
Location: Wisconsin USA
Age: 60
Posts: 839
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The CLK 90 mod is another "Your mileage will vary" hack. I have also heard some A3640 owners say it does not work @ 25 MHz and it's very easy to move the jumper back to the original connection.
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05 September 2013, 10:34
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#24 |
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Thalion Webshrine
Join Date: Jan 2004
Location: Oxford
Posts: 14,337
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I had instability on my system until I replaced all the electrolytic capacitors on the motherboard and in the power supply.
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05 September 2013, 15:35
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#25 |
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Registered User
Join Date: Apr 2012
Location: Canada
Age: 44
Posts: 910
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@alexh, this has been done already. I have a stable +5.1V on the +5 rail, with no variation under load.
Today I should be receiving the 7ns 16v8 gals that should (in theory at least) be compatible with my programmer. Finding this to be a big hit and miss. I tried a lot of different (brand new!) chips that the programmer will erase but not program. I will try undoing the clock 90 and/or changing the crystal once I get the new chips. |
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05 September 2013, 17:04
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#26 |
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Thalion Webshrine
Join Date: Jan 2004
Location: Oxford
Posts: 14,337
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What about the patch level in your AmigaOS? I've found that the more "custom" patches I have the more unstable my AmigaOS3.x system is.
The last really stable system I had was AmigaOS 3.9 BB#3 |
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06 September 2013, 04:02
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#27 | |
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Registered User
Join Date: Apr 2012
Location: Canada
Age: 44
Posts: 910
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Quote:
Anyway: Making progress... OK, so I got 7ns 16v8s. Replaced U208, everything works great now. Did a simple overclock (change oscillator) to 33 Mhz, the system run completely stable, for a long while, even under stress. The new MC68040RC40 chip gets barely warm. Nice!!! Replace U203 with a 7ns chip, the system wouldn't boot (insert Captain Kirk yelling "Khaaaaaan!" here). OK well, this is the next step to investigate... but at least it's stable now, although no Zorro boards attached yet. Look at these figures:    55% integer performance increase, 16% graphics and 35% floating point. |
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