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C070243 REV.H

ST & STM motherboards.
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exxos
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C070243 REV.H

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exxos
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Re: C070243 REV.H

Post by exxos »

Another one but with some odd adapter RAM board :shrug:

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troed
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Re: C070243 REV.H

Post by troed »

That looks to be a rather neat RAM board actually. The regular 41256 chips are 16 pin 256kx1, and the only real option is to piggyback another 512KB on top of the existing. That board takes 18 pin chips which means you can use 421000 (511000 in this case) which are 1Mx1. So, that should be a 2MB RAM upgrade.
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HCRX27
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Re: C070243 REV.H

Post by HCRX27 »

Dear Exxos,
there's no information on bus-resistors replacement for that exact motherboard (C070243 REV.H):
viewtopic.php?f=17&t=2235#p27504

Could you please advise if all of them can be safely replaced with 2.2kOhm? There are 6 of them, if I see it right.
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exxos
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Re: C070243 REV.H

Post by exxos »

HCRX27 wrote: 15 Sep 2025 07:47 Dear Exxos,
there's no information on bus-resistors replacement for that exact motherboard (C070243 REV.H):
viewtopic.php?f=17&t=2235#p27504

Could you please advise if all of them can be safely replaced with 2.2kOhm? There are 6 of them, if I see it right.
Its not something I have tried or documented on the STM. I suggest not changing them unless you have issues.
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HCRX27
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Re: C070243 REV.H

Post by HCRX27 »

There are issues with loading HD adapted games from SidecarT or IDE HDD after I replaced CPU to 68HC000 in HyperCache turbo (16MHz + cache), because the NMOS wanted to burn the keyboard above it alive ;-) Loading from Ultrasatan with no SidecarT attached is working fine, though, with good overall stability.
So I guess, replacing them all with 2.2kOhm should do no harm either for HC or if I stay with NMOS?
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Re: C070243 REV.H

Post by exxos »

HCRX27 wrote: 15 Sep 2025 09:08 There are issues with loading HD adapted games from SidecarT or IDE HDD after I replaced CPU to 68HC000 in HyperCache turbo (16MHz + cache), because the NMOS wanted to burn the keyboard above it alive ;-) Loading from Ultrasatan with no SidecarT attached is working fine, though, with good overall stability.
So I guess, replacing them all with 2.2kOhm should do no harm either for HC or if I stay with NMOS?
I'm not aware of any issues no. I'm sure others have changed them without issue.
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HCRX27
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Re: C070243 REV.H

Post by HCRX27 »

Perfect, thanks a lot!
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