> "der Mouse" <mouse@Rodents.Montreal.QC.CA> wrote:
>
> >> No, source of the confusion is that you think the GX chip is a PGA
> >> socket.
>
> > <grin>  No, source of confusion is far more fundamental than that --
> > have two such machiines here.  *Tested* machine 1, *examined* machine
> > 2!  (Of course, machine 2 is the one missing the chip).   <:-(
>
> !!  I didn't think the GX in a LX was socketed!  Indeed, in the one I
> have at hand, I'm pretty sure it's not (I even took the board out to
> get a better look).

This is most *definitely* a socket.  Black plastic.  Machined pin ferrules.
Your comment about your board NOT having a socketed device sent alarm bells
ringing so I pulled the board out of this one.  It doesn't take a rocket
scientist
to realize -- once you've seen the solder side of the PCB -- that the socket
is "not native".  Machine came from a local University's "surplus" sale.
Undoubtedly, some enterprising student depopulated the original component(s)
and installed the PGA socket.  Possibly to support some "customization"
required for a research project, etc.

Now, do I trust that he knew what he was doing in the process?  And,
that he didn't lift any foils when he pulled the old device?? (removing
PGA's
is a ball-buster)  Gee, maybe the reason this particular unit was placed
in the surplus sale was because it's value had declined to -0- !

Crap.

> > So, my question still stands -- can I steal the GX out of a cg6 SBUS
> > card or am I better off installing the card *in* the LX chassis?
>
> Depends on your risk tolerance. :-)  The latter is much more nearly
> certain to work and much less likely to fry anything.

Given my speculations, above, I don't think I want to risk toasting the
GX chip out of the SBUS card just to determine if the alleged student
has a promising career as a technician ahead of him or not!  And, I
don't even think I want to risk putting the SBUS *card* into the machine
for fear that something else might be fried and compromise that card.

Crap.

Crap.

Double crap!

> However, never having tried it, my guess would be a definite "maybe". :)
> I have at hand now an LX and a cg6 that have SunGX chips that appear
> basically identical.  The only difference I can see is that a little
> printing is different.  On the LX, the three rows of fine printing at
> the bottom read
>
> 1134A2
> 9414
> 7414117
>
> whereas on the cg6, they read
>
> 1134A2

First number is probably chip identifier/part number.

> 9242

This second number is likely the date code.  42nd week of 92?

> 7495155
>
> However, I own multiple cg6s (of which only one is near me now), and
> they don't all use chips this similar; indeed, one of them is a
> dual-slot SBus card and is utterly different from the others.  I have
> no idea whether the various "big chips" are pin-compatible.

I have three different cg6 SBUS cards here.  P/N's  501-1645, 501-1481
and 501-1672.  The later beiing a single width card while the other two
are double width.   The double width cards *look* identical (to each other).
Same component layouts, same "big chips", etc.  (though the - 1645 uses
an AMD part for the RAMDAC while the -1481 uses a Brooktree part;
they *may* be pn compatible devices, etc.  <shrug>)

Aside from being a single width card, the -1672 uses a different chipset
entirely.  While the other two had several "big chips", the -1672 crams it
all
into one PGA boldly labeled "SunGX".  And, the 32 ZIP VRAMs on the
double wide card are replaced by a set of 8 SMT devices on the siingle
width card.

Worth noting is the single width card uses the Brooktree RAMDAC.
Presumably, this card is more recent than the double wides.  Maybe the
AMD RAMDAC went EOL and the -1645 was redesigned as the
-1481 just to support this change?

> > I.e. is there any difference between the "onboard cg6" and an "SBUS
> > cg6" (besides the fact that the SBUS card "costs" me a slot and some
> > extra power...)?
>
> I have found at least one difference in the case of the LX and SBus
> card I have at hand: the surrounding video electronics are different.
> With a particular adapter cable and either of two different peecee
> monitors, the SBus card works and the onboard framebuffer doesn't drive
> anything the monitor recognizes as sync.  (It's not that the onboard
> framebuffer is fried; they work equally well with a Sun monitor.)

Hmmm... interesting.  Perhaps I'll throw these two different double wide
cards into a machine and see how/if they behave.  Though I'll have to
dig up an adapter and a multisync monitor if I want to try a non-Sun
monitor.

> Granted, that difference isn't very relevant to your main question.

No.  But it might coincide with the speculated redesign of the double
wide card (?) -- perhaps one version doesn't drives sync-on-green while
the other drives a composite sync signal, etc.

--don