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From: Ivan Capan on 7 Nov 2006 19:44
Symptoms: when I type GO64 and press Y, the screen blanks and says "out
of memory error". The same thing is when I hold the C= during booting.
I tried with a C64 cartridge. The title screen shows, but when I start
any of the programs, none of them works.
What could be the problem? I have read
http://personalpages.tds.net/~rcarlsen/cbm/C128-IC.txt
but none of the scenarios are similar.
From: Ray on 7 Nov 2006 22:24
> Symptoms: when I type GO64 and press Y, the screen blanks and says "out of
> memory error". The same thing is when I hold the C= during booting. I tried
> with a C64 cartridge. The title screen shows, but when I start any of the
> programs, none of them works. What could be the problem? I have read
> http://personalpages.tds.net/~rcarlsen/cbm/C128-IC.txt but none of the
> scenarios are similar.

Ivan,
That error message usually means one of the RAM chips is bad. If an IC is
open or shorted, you get a blank screen, but with this kind of partial failure,
you get an abnormal number of bytes free (or zero) at startup. One trick I use
to find the bad chip is to "piggyback" a known good IC on top of each board RAM
chip (there are 16 4164 DRAMs in a flat 128) and power up the computer to see
if the bytes free changes. Note that the board ICs may be marked in a number of
different ways depending on the manufacturer, but they're all generic 4164.
Anyway, take a 4164 IC and press it down over each of the board RAM chips,
one at a time, then power up the computer in 64 mode and see if you get the
normal number of bytes free (38911). Make sure you orient the chip correctly...
there is a notch or dot at one end that should match the board IC. Before you
apply power, make certain all of the pins are touching the same pins of the
board IC, and that none are shorted. If you squeeze the pins of the test chip
inward slightly, it will fit and hold itself over the board chip... but you can
also hold it with your fingers without a problem. There is only five volts
there so no possibility of a shock hazard. It's unlikely there is more than one
bad IC, so if you hit one that makes the screen bytes-free change (even if it's
still incorrect), change that one. That should do it.

Ray

--

My return addy is spamblocked. To reply, remove the zeroes.
From: Sam Gillett on 8 Nov 2006 00:55

"Ivan Capan" wrote ...

> Symptoms: when I type GO64 and press Y, the screen blanks and says "out
> of memory error". The same thing is when I hold the C= during booting.
> I tried with a C64 cartridge. The title screen shows, but when I start
> any of the programs, none of them works.
> What could be the problem? I have read
> http://personalpages.tds.net/~rcarlsen/cbm/C128-IC.txt
> but none of the scenarios are similar.

Before reading Ray's reply, I was thinking it might be the C64 ROM. The
ROM's might be OK for 128 mode, but not for 64 mode. However, if Ray thinks
it is a RAM chip, check that first.
--
Best regards,

Sam Gillett

Change is inevitable,
except from vending machines!



From: Patrick de Zeester on 8 Nov 2006 12:31
Sam Gillett wrote:
> "Ivan Capan" wrote ...
>
>> Symptoms: when I type GO64 and press Y, the screen blanks and says "out
>> of memory error". The same thing is when I hold the C= during booting.
>> I tried with a C64 cartridge. The title screen shows, but when I start
>> any of the programs, none of them works.
>> What could be the problem? I have read
>> http://personalpages.tds.net/~rcarlsen/cbm/C128-IC.txt
>> but none of the scenarios are similar.
>
> Before reading Ray's reply, I was thinking it might be the C64 ROM. The
> ROM's might be OK for 128 mode, but not for 64 mode. However, if Ray thinks
> it is a RAM chip, check that first.

The C128 doesn't perform a memory check when powered up (the bytes free
in the startup message is hard coded), the C64 does. Hence it is
conceivable that when one of the RAM chips fail, in 128 mode the C128
appears to be fine, while in 64 mode it immediately reports 'out of
memory' or an unusual amount of bytes free. In this case my money would
be on a bad RAM chip.
From: bluebirdpod on 8 Nov 2006 13:03

Ray wrote:
> > Symptoms: when I type GO64 and press Y, the screen blanks and says "out of
> > memory error". The same thing is when I hold the C= during booting. I tried
> > with a C64 cartridge. The title screen shows, but when I start any of the
> > programs, none of them works. What could be the problem? I have read
> > http://personalpages.tds.net/~rcarlsen/cbm/C128-IC.txt but none of the
> > scenarios are similar.
>
> Ivan,
> That error message usually means one of the RAM chips is bad. If an IC is
> open or shorted, you get a blank screen, but with this kind of partial failure,
> you get an abnormal number of bytes free (or zero) at startup. One trick I use
> to find the bad chip is to "piggyback" a known good IC on top of each board RAM
> chip (there are 16 4164 DRAMs in a flat 128) and power up the computer to see
> if the bytes free changes. Note that the board ICs may be marked in a number of
> different ways depending on the manufacturer, but they're all generic 4164.
> Anyway, take a 4164 IC and press it down over each of the board RAM chips,
> one at a time, then power up the computer in 64 mode and see if you get the
> normal number of bytes free (38911). Make sure you orient the chip correctly...
> there is a notch or dot at one end that should match the board IC. Before you
> apply power, make certain all of the pins are touching the same pins of the
> board IC, and that none are shorted. If you squeeze the pins of the test chip
> inward slightly, it will fit and hold itself over the board chip... but you can
> also hold it with your fingers without a problem. There is only five volts
> there so no possibility of a shock hazard. It's unlikely there is more than one
> bad IC, so if you hit one that makes the screen bytes-free change (even if it's
> still incorrect), change that one. That should do it.
>
> Ray
>
> --
>
> My return addy is spamblocked. To reply, remove the zeroes.

Well another option would be to test your memory while in 128 mode,
Both 64 and 128 mode use the same memory, 128 just uses more of the
RAM, I would first try to find a 128 version of a diagnostic checker
and see what happens in 128 mode. If it verifies correctly in 128 mode,
then I would not suspect bad ram. Then there is something else wrong.

-bluebirdpod

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