jackin@vehka.uta.fi (Markku M{enp{{) (10/01/90)
I have a Mega ST 2 which I am planning to update to 4 MB.
I have now 16 empty sockets available, but putting 80ns
chips didn't work. It was quite expectable original chips
being 150ns.
Do 120ns chips work or do I need 150ns (rare in 1MB chips) ?
Is there anything else to do apart putting chips in and
soldering capasitators (as is done in original 2 MB) ?
I wanna see my Spectre work with 4MB !!!!
Thanks,
Markku
--
Markku M{enp{{
email : jackin@vehka.uta.fi
phone : 358 31 561 575 (in Finland (931) 561 575)wilko@idca.tds.PHILIPS.nl (W.C. Bulte) (10/01/90)
In article <1599@kielo.uta.fi> jackin@vehka.uta.fi (Markku M{enp{{) writes: >I have a Mega ST 2 which I am planning to update to 4 MB. > >I have now 16 empty sockets available, but putting 80ns >chips didn't work. It was quite expectable original chips >being 150ns. > >Do 120ns chips work or do I need 150ns (rare in 1MB chips) ? >Is there anything else to do apart putting chips in and >soldering capasitators (as is done in original 2 MB) ? >Markku M{enp{{ >email : jackin@vehka.uta.fi >phone : 358 31 561 575 (in Finland (931) 561 575) First of all, I dont't see any reason why 80ns chips shouldn't work. However, you might have a few resistors missing for the second DRAM bank. These resistors are put in series with CAS and RAS lines (and R/W ??) connected to the MMU chip. Some motherboards have them installed, even on Mega 2 boards, but some don't. See if you can find them.. If you want to know what speed your old chips are, please mail me the type# I'll see if I can find them in the databooks. Good luck, _ ______________________________________________________________________ | / o / / _ Wilko Bulte Domain: wilko@idca.tds.philips.nl |/|/ / / /( (_) uucp : [mcsun,hp4nl]!philapd!wilko * Philips Information Systems Nederland phone: 055-432372 fax: 055-432103 ____________________________________________________________________________
pegram@uvm-gen.UUCP (Robert B. Pegram) (10/02/90)
From article <1599@kielo.uta.fi>, by jackin@vehka.uta.fi (Markku M{enp{{):
> I have a Mega ST 2 which I am planning to update to 4 MB.
> I have now 16 empty sockets available, but putting 80ns
> chips didn't work. It was quite expectable original chips
> being 150ns.
> Do 120ns chips work or do I need 150ns (rare in 1MB chips) ?
Yes, they should work, I have 100ns chips in my expanded 520.
80ns may be pushing the refresh rate, but I haven't looked into it.
I believe there was a note about it on c.s.a.st last year.
> Is there anything else to do apart putting chips in and
> soldering capasitators (as is done in original 2 MB) ?
I hope someone else expands on this as I can only suggest things from
possibly faulty memories (my own, not the ST's 8-). 1) You need to
have all the correct resistors in place for things to work. 2) I seem
to recall that Atari sent out some Mega 2s that have faulty MMUs, i.e.
they can only handle 1 bank instead of the regular 2. The numbers of
these chips are known, and I might be able to dig the article up (US
ST World I believe) if no one else can elaborate on this. If you want
to do something about this *now*, and have access to a working Mega 4
or upgraded Mega 2, open it up and note the MMU numbers and look for
resistors (RAS, CAS, etc. for bank 2, there are plenty of them I
believe) that are not in your Mega. Add any missing resistors
(correct values and tolerances please, just match the color codes or
markings) and if it still doesn't work, swap MMUs. BTW, does it still
work properly with 2Meg? In any case, please check your soldering
again for bad (cold) solder joints and for "bridged" traces.
> I wanna see my Spectre work with 4MB !!!!
Me too, but I need a Spectre 1st, then the new memory board and xtra 2 Meg 8-).
> Thanks,
> Markku
> --
> Markku M{enp{{
> email : jackin@vehka.uta.fi
> phone : 358 31 561 575 (in Finland (931) 561 575)
Good Luck,
Bob Pegram
Internet domain: pegram@griffin.uvm.edu
UUCP: uunet!uvm-gen!pegramfortinp@bwdls56.bnr.ca (Pierre Fortin) (10/03/90)
In article <1599@kielo.uta.fi>, jackin@vehka.uta.fi (Markku M{enp{{) writes: > I have a Mega ST 2 which I am planning to update to 4 MB. > > I have now 16 empty sockets available, but putting 80ns > chips didn't work. It was quite expectable original chips > being 150ns. I installed 70ns chips which run just fine. > > Do 120ns chips work or do I need 150ns (rare in 1MB chips) ? > Is there anything else to do apart putting chips in and > soldering capasitators (as is done in original 2 MB) ? YES!! You need to add 3 resistors (33 ohm) in the area surrounded by the existing RAMs, ROMs and the boards edge; somewhere around R61 if I remember correctly. There are at least 3 missing resistors there... > > I wanna see my Spectre work with 4MB !!!! > > Thanks, > Markku > > -- > Markku M{enp{{ > email : jackin@vehka.uta.fi > phone : 358 31 561 575 (in Finland (931) 561 575) Cheers, Pierre Pierre Fortin Bell-Northern Research I know, my postings are Internet Systems P.O.Box 3511, Stn C terse and humourless. So? (613)763-2598 Ottawa, Ontario RIP: aptly named protocol Canada K1Y 4H7 AppleTalk: Adam&Eve's design