Re: Yet another Transwarp GS upgrade question

["Mark Cummings" <NOTfigjams@primus.com.au>]

"Tim Haynes" <timhaynes@alumni.NO.SPAM.PLEASE.uwaterloo.ca> wrote in message
news:bjvFa.49267$3Sm.47037@news01.bloor.is.net.cable.rogers.com...
> My TWGS has always been a bit flakey - one of the previous owners appears
to
> have been at work getting its speed up, and I'm not sure if the current
> configuration is solid or not:
>
> Crystal:  28MHZ
> Gals:  1A, 2B, 3D, 4B, 5A, 6A, 7A, 8B
> Processor:  W65C816PL
> Eprom:  TWGS 1.8s
> Cache:  32K (I'm assuming it's 32K - that's what is reported in the
control
> panel... I have 3 chips on it that are 35ns:  Japan 9116 / HM62832HLP-35 /
> 00016990)
>
> It seems to flake out on heavy disk activity... but also dies somewhat
> randomly at other times.  I'm guessing the crystal is a bit nonstandard.
> Can anybody tell me for sure?  Perhaps the GALs aren't right...?

hi Tim,

the XTAL should be a square shiny package with 4 pins, called a 1/2 size
clock oscillator IIRC.
the XTAL gets divided down by 4, so you actually have a 7MHz TWGS, which is
pretty stock standard speed. I think they came out as 6MHz originally then
later 7MHz. (mine was a 7MHz version originally). if the CPU has
a -6, -7, -8, or -14 ?, it means 6, 7, 8 or 14MHz respectively. no '-'
indicates a 6MHz CPU, which probably won't run at 7MHz. If the XTAL seems a
bit loose, as mine did you can try bending the legs in a slight curve, which
will help them make better contact and hold it in better.

the RAM sounds like it has been upgraded to 32K if that is what has been
reported in the Control Panel, but it should be -10, -15 or -20 ns if you
have a faster CPU, not -35ns which sounds a bit slow, but is probably OK for
a 7MHz CPU. I think the stock RAM on a 7MHz model was about that, my old 8K
SRAMs were 7164s, but no speed data is printed on them, I'd have to look it
up in a data book.
32K cache chips will be marked 61256-15 or similar, and these days are
normally 300mil width (0.3"). I'm sure there are lots of compatable chips
with widely varying part numbers, only a data book will tell.

if your original AE cache board has been modified, it may have 300mil or
600mil chips. 300mil chips have to have the legs bent out beyond 45deg to
fit the board. 600mil chips will fit in the old sockets, but are pretty rare
to find. I'd have to check the part number of your chips in a data book,
because they sound different to the ones I have.

I have the SSH System 32K cache board on mine, but I also have a modified
original cache board which I made after reading Tony Diaz's TWGS
modification info at www.apple2.org
the SSH board is more reliable in mine, but I think my TWGS is also flakey,
because it crashes occasionally at 10MHz or 12.5 MHz with either board. At
16MHz it doesn't get past the splash screen.

my GALS are 1A, 2B, 3C, 4A, 5A, 6A, 7A, & 8A. after reading Tonys info, you
should be able to use any GAL versions, just that they were designed to slow
down the CPU a bit under certain conditions to avoid problems with faster
XTALS. I guess that means that the Rev A GALS are best if you want absolute
maximum speed. The only place I you may be able to get alternate GALs would
be through Joachim Lange at SHH///Systems (at a price), but I'd say the
flakeyness could be caused by other things. If you can, try swapping the
cache chips first.

Mark