[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: IIe faulty RAM ?
Wayne Stewart wrote:
>
> Mark Cummings wrote
> > I am suspicious of the soldered in RAM, which is 2 of 41464C-10. Before I go
> > desoldering, can anyone shed any experience with RAM faults and the
> > symptoms.
>
> I haven't had a problem with a platinum IIe but I've had Ram problems in other
> enhanced IIes. Random characters on the screen was one of the symptoms I
> encountered in some units. My impression is that what you get depends on how
> bad the RAM is and where it's faulty. In the worst case I had a screen that
> was mostly white blocks and a squeal coming out of the speaker.
>
> > Would the inbuilt diagnostics (Ctrl-Option-Reset) run correctly if the RAM
> > was faulty, if so how would it display the result, since the text screen is
> > memory mapped.
>
> The self test does test the RAM and and shows where the bad RAM is provided it
> will run at all. If the RAM is dead or bad in the wrong spot then the self-test
> won't work.
>
> > Also, should it still make any sounds, as this would be
> > addressed outside of RAM space ?
>
> I know it can still make sounds or at least squeals with very dead RAM. Whether
> that applies in all cases I don't know. My personal experience is limited to
> only about 20 or so IIes with bad RAM.
>
> Wayne
This sounds strangely familiar to when my old //e (unenhanced, 2 disk ][
drives, Monitor ///, 128k RAM, and a Saturn Systems 128K RAM card) blew
the 74LS266 chips on the Saturn Systems RAM card and then, consequently
blew the 74LS05 chip on the disk ][ controller card. Just garbage
everywhere on the screen. Taking the disk ][ controller and the RAM
card out returned the //e to normal function, except that I could only
load stuff from tape. Never fixed the Saturn RAM card, but did fix the
disk ][ controller card, so I could use it.
-J
--
++++ John H. Laughlin, CS Student @ Bellevue Community College ++++++++
+ VCOA member# 9842A |'73 145E B20F M40 373K mi - 600K km +
+ Duvall, WA 98019-0778 |'82 242Ti B21FT M46 376K km - 234K mi +
+'81 242DL B23E M46 293K mi |'83 245Ti B21FT AW71 164K mi - 264K km+
+'85 245GL B230F M46 238K mi |'87 744Ti B230FT AW71 154K mi(249K km)+
++++++++ http://www.premier1.net/~john242ti/volvo.html ++++++++++++++++