scs@itivax.iti.org (Steve Simmons) (10/19/89)
I recently added a combo card with 1.5MB to lokkur, which already had .5 on the motherboard and 2 .5MB expansion cards. Instead of getting 3.0MB, there's only 2.0. Skipping the gruesome details, I've tried everything I can think of -- change slots, changing jumpers on the combo, you name it. And yes, the combo card does work correctly -- take out the two .5MB expansion cards, and the combo alone provides a full 1.5MB expansion. Three questions: First, why does one of the three jumpers on the combo card seem to be ignored? Second, there appear to be no jumpers whatsoever on the .5MB cards. Is this correct? Third, does anybody out there have a working configuration like the one I'm trying for?
mvadh@cbnews.ATT.COM (andrew.d.hay) (10/19/89)
In article <4224@itivax.iti.org> scs@itivax.iti.org (Steve Simmons) writes:
"
"I recently added a combo card with 1.5MB to lokkur, which already
"had .5 on the motherboard and 2 .5MB expansion cards. Instead of
"getting 3.0MB, there's only 2.0.
the combo card is overlaying the ram cards. the only way to get more
ram is to upgrade the mother to 2Mb or upgrade a ram card to 2Mb; both
take a lot of work, but not much engineering.
"Second, there appear to be no jumpers whatsoever on the .5MB cards.
there are 4(5?) of them near the panel; all but one get changed in
upgrading the board to 2Mb. the default settings are etched and must
be cut...
--
Andrew Hay +------------------------------------------------------+
Clay Fancier | SAVE THE SKEETS! |
AT&T-BL Ward Hill MA | OCTOBER IS NATIONAL SKEET MONTH |
a.d.hay@att.com +------------------------------------------------------+tkacik@rphroy.UUCP (Tom Tkacik) (10/19/89)
In article <4224@itivax.iti.org> scs@itivax.iti.org (Steve Simmons) writes: > >I recently added a combo card with 1.5MB to lokkur, which already >had .5 on the motherboard and 2 .5MB expansion cards. Instead of >getting 3.0MB, there's only 2.0. Skipping the gruesome details, You can only have 2 MB total expansion memory. With the 1.5 MB combo board and the 2 .5 MB memory boards, you have exceeded that limit. But that does not explain why you do not the full 2. MB expansion memory. That is because AT&T messed up the design of the combo board. There is only one configuration that allows both a 1.5 MB and a .5 MB board to be used together. The two boards must in the correct slots, (I do not remember which ones, but it is listed in the s4bus spec.), and the 1.5 MB board must be addressed correctly. AT&T did not design the memory addressing in the combo board to allow this. Too bad :-(. There is some hope however :-). John Milton (in another heplful posting) has posted instructions on how to modify the combo board. I seem to have misplaced them, but just maybe if wee ask nicely John will repost or send them to you. -- Tom Tkacik GM Research Labs, Warren MI 48090 uunet!edsews!rphroy!megatron!tkacik Work Ph: (313)986-1442 "If you can't stand the bugs, stay out of the roach-motel." Ron Guilmette
elliston@msdrl.UUCP (Keith Elliston) (10/26/89)
While on the subject of memory.... I have an old 7300, with 512k on the mother board and NO expansion memory. I am in desperate need of more memory. So.. does anyone have an expansion board or combo board that they would like $$$ for? Or.. does anyone have an empty combo board or .5 expansion that i could put some dips on? I have a bunch of 256k dips (150 ns) from some Macintosh memory upgrades that are just dieing to jump into my unixpc. Anyone able to help me on this one... I NEED MEMORY!!! Keith uunet!msdrl!elliston
jlw@lzga.ATT.COM (J.L.WOOD) (10/26/89)
John McMillan stated that the 7300 would fail with many standard 256Kbit parts. I have observed this to be true. Unfortunately the memory diagnostics do not always detect this. What happened to me a few years ago was that I was populating 2-EIA + 1.5 Meg expansion cards with WECo 256KBit parts supposedly industry standard. The Combo card tri-states the 8-th address bit as it strobes across the addresses refreshing the DRAMS. The WECo chip couldn't handle this and failed to properly refresh. The memory diagnostics didn't fail because their algorithms caused affected memory locations to be revisited well within the memory refresh interval thus refreshing whole rows of memory. I didn't get my failures until I started loading and running UNIX which will load code into memory and then revisit it only when necessary. I got panic traps up to 10 minutes after reloading UNIX since not all of my memory on any given machine was of this type. Joe Wood
jcm@mtunb.ATT.COM (was-John McMillan) (10/26/89)
In article <388@msdrl.UUCP> elliston@msdrl.UUCP (Keith Elliston) writes: >... I have >a bunch of 256k dips (150 ns) from some Macintosh memory upgrades that are >just dieing to jump into my unixpc. Just a note: the demands of the 3B1/7300 are such that SOME generic chips malfunction. Fujitsu and Fairchild are fine, as I recall, but others may fail. Run the RAM test diagnostics. jc mcmillan -- att!mtunb!jcm
jan@bagend.UUCP (Jan Isley) (10/27/89)
In article <1685@mtunb.ATT.COM> jcm@mtunb.UUCP (was-John McMillan) writes: >In article <388@msdrl.UUCP> elliston@msdrl.UUCP (Keith Elliston) writes: >>a bunch of 256k dips (150 ns) from some Macintosh memory upgrades that are >>just dieing to jump into my unixpc. What? Every Mac I have seen, which is quite alot, has SIMMS, not DIPS. > Just a note: the demands of the 3B1/7300 are such that > SOME generic chips malfunction. Fujitsu and Fairchild > are fine, as I recall, but others may fail. > Run the RAM test diagnostics. ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Yes, yes, dozens of times, yes! It may fail after passing the diagnostics the first hundred times! I have seen it happen more than once. Get them suckers good and hot and put them in the test loop overnight. I have seen many motherboards with TI, Motorola, and Hitachi 256k chips. I have successfully used many (thousands each) TI, Motorola, and Samsung 256k 120ns chips in UNIX-PCs with 0 failures. 150ns chips seems to be harder to find than the 120ns variety. The only ones I have seen fail were Fujitsu. ( 3 out of many thousands ) -- jan@bagend {..gatech..}!bagend!jan (404)434-1335 voice@home
scs@itivax.iti.org (Steve Simmons) (10/27/89)
jan@bagend.UUCP (Jan Isley) writes: >In article <1685@mtunb.ATT.COM> jcm@mtunb.UUCP (was-John McMillan) writes: >>In article <388@msdrl.UUCP> elliston@msdrl.UUCP (Keith Elliston) writes: >>>a bunch of 256k dips (150 ns) from some Macintosh memory upgrades that are >>>just dieing to jump into my unixpc. >> Just a note: the demands of the 3B1/7300 are such that >> SOME generic chips malfunction. Fujitsu and Fairchild >> are fine, as I recall, but others may fail. >Yes, yes, dozens of times, yes! It may fail after passing the diagnostics >the first hundred times! I have seen it happen more than once. Get them >suckers good and hot and put them in the test loop overnight. Speaking only as a satisfied customer: I bought 1.5MB of used 150ns DRAMs from Micro-C. It cost me $108.00 plus shipping (yes, $2.00 per chip). Their price is now $1.75, but bear in mind they have a $100 minimum order. They took my Master Card number by phone and the package arrived five days later. The RAM arrived clean, straight, and properly packed including being entubed. It runs fine in my combo card. Mine are Fujitsu chips, but this varies. Micro-C is at 11085 Sorrento Valley Ct, San Diego, CA. 92121, 619-522-1213. -- Steve Simmons scs@iti.org Industrial Technology Institute "I forgot the baby." -- P. Honeyman
psfales@cbnewsc.ATT.COM (Peter Fales) (10/28/89)
In article <10383@cbnews.ATT.COM>, mvadh@cbnews.ATT.COM (andrew.d.hay) writes: > In article <4224@itivax.iti.org> scs@itivax.iti.org (Steve Simmons) writes: > " > "I recently added a combo card with 1.5MB to lokkur, which already > "had .5 on the motherboard and 2 .5MB expansion cards. Instead of > "getting 3.0MB, there's only 2.0. I was waiting for someone who knows a little bit more about this to say something, but since I haven't heard anything, I will take a stab... As I understand it, the UNIX-PC supports 2MB of expansion memory. Each slot has .5 MB dedicated to it, and when you plug in a 512K board, it uses the connector to determine which slot it is plugged into, and therefore which address range to use. If you have a 1.5MB board, it ignores the slot position, and just uses all three .5MB banks. John Milton has posted instructions for modifying a 512K board to look as if it is plugged into the phantom "fourth slot" and used this range which is normally used only by the 2MB expansion card. If you use this fix, you could have .5MB on the mother board, a 1.5MB combo, and a .5MB expansion card, for a total of 2.5MB. -- Peter Fales AT&T, Room 5B-420 2000 N. Naperville Rd. UUCP: ...att!peter.fales Naperville, IL 60566 Domain: peter.fales@att.com work: (312) 979-8031