Subject: Re: what's this machine check mean?
To: None <>
From: der Mouse <mouse@Rodents.Montreal.QC.CA>
List: port-alpha
Date: 04/15/2000 14:54:25
>> The machine seems to be accurately described in the [...]
> This is known as a "NoName" (confusing name..)

Heh. :-)

>> [...] 4x30pin->72pin adapters [...]
> These 30->72 pin converters will most likely overload (much more
> chips!) the memory bus of the machine.

I actually have four adapters, two each of two sorts.

One sort is completely passive - pc board and 30-pin sockets, nothing
more than that.

The other sort has five small chips surface-mounted on it.  Four of
them are marked "F04" and "XAE530", with a Motorola logo.  The fifth
says, on one adapter, "F08" and "XAA512" (also with the Motorola logo);
on the other, "F08" and "ZAY510" (and the logo).  There are also eleven
surface-mount two-terminal devices.  Seven of them are marked C1
through C7 and are presumably power-supply deglitching capacitors (five
are next to the five surface-mount chips, the other two next to the
30-pin sockets).  The other four are marked R1, R2, R5, and R6.  (There
are solder pads marked R3 and R4 but no resistors on them.)  The
surface-mount ICs are 14-pin and hence have pin count enough to be
address buffers (data buffers are, of course, unnecessary).  Using the
SIMM socket pinout in the manual whose name I deleted above, I can
trace many of the etch runs on the adapter, and it certainly looks as
though the surface-mount chips are address buffers.

> Be careful, you can screw the CPU this way, I once had a friend with
> a fried CPU, a lot of logic directly connects to the CPU without
> buffer chips in between.

Given the apparent buffer chips on the adapters, I risked it.  I did
leave the other two memory sockets empty, trying to do what I could to
reduce load.

The bad news is, it didn't work: even after waiting a full minute, I
got nothing out the console serial port.  (It normally starts printing
stuff about 45 seconds after power-up.  I don't have the diagnostic
LEDs hooked up.)

The good news is, it apparently didn't fry anything; when I switch back
to the 80ns SIMMs, it works as well as it ever did - that is to say, it
boots and runs for a little while, then machine-checks reporting a pc
in lca_mem_read_1.

> I have the latest copy of the NoName OEM guide at
> if you need it.

Thank you.  Being fetched as I type.

					der Mouse

		     7D C8 61 52 5D E7 2D 39  4E F1 31 3E E8 B3 27 4B