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- Newsgroups: comp.sys.zenith
- Path: sparky!uunet!cs.utexas.edu!sdd.hp.com!ux1.cso.uiuc.edu!news.cso.uiuc.edu!uxa.cso.uiuc.edu!dalke
- From: dalke@uxa.cso.uiuc.edu (dalke andrew)
- Subject: Re: Z-150 PC HD type?
- References: <1993Jan24.185040.30660@ns1.cc.lehigh.edu>
- Message-ID: <C1EnEz.n39@news.cso.uiuc.edu>
- Summary: The author discusses some old Zenith computers
- Sender: Andrew Dalke <dalke@uxa.cso.uiuc.edu>
- Organization: University of Illinois at Urbana
- Date: Mon, 25 Jan 1993 10:20:59 GMT
- Lines: 93
-
- In the referenced article mcg2@ns1.cc.lehigh.edu (Marc Gabriel) writes
- about Z-150 PCs:
- >Does anyone remember what kind of hard drive the old Z-150 PCs used? Was it
- >an MFM? RLL? Proprietary format? The manuals say it is called a
- >"Winchester" drive, but of course this means nothing in the real world.
- >
- >Sorry that I have to revive ancient history. Any help would be appreciated.
-
- First off, ancient? I'm running on a H-151 PC at 4.77 MHz. Not
- only is it a Zenith computer but it was distributed by Heathkit so
- you could assemble it yourself (or I could) for $200 less. Okay, so
- a memory delay line died and I wore out the original A: drive - that's
- _all_ that's gone bad in terms of hardware. How many 486-50's will say
- that in ten years?
-
- Okay, now that that's over. I didn't actually get the HD with the 151.
- (I had to wait about three years for that - but I was happy since I had
- floppies instead of tapes!) When I did, it was a Seagate. Hopefully
- the following will be of help.
-
- Product information, Seagate drive, (c) 1987
-
- ST412 Interface drives using MFM encoding at 5 MB / sec
- MB # heads cyl.
- ST125 21 4 615
- ST138 32 6 615
- ST225 21 4 615
- ST251 42 6 820
- ST251-1 42 6 820
- ST4038 31 5 733
- ST4051 42 5 977
- ST4053 44 5 1024
- ST4096 80 9 1024
-
- ST412 Interface Drives using RLL (2.7) encoding at 7.5 MB /sec
- ST138R 32 4 615
- ST157R 49 6 615
- ST238R 31 4 615
- ST251R 43 4 820
- ST277R 65 6 820
- ST4144R 122 9 1024
-
- SCSI is listed also, but I doubt that that is what you have.
-
- Now for my problems. I recently traded some RS-232 cable for
- a CPU/memory board and a CGA/floppy card.
-
- The CPU worked once and raised my Norton SI form 1.0 to 1.6 so
- I assume that it is 4.77/6 MHz board (there is a switch on the back).
- (The crystals are 14.31.. MHz (=3*4.77) and 24 MHz(=4*6=3*8).
- After a bit, the computer started complaining about memory
- problems. The ROM debugger pointed out a bad chip at U208. I
- swapped it with U209 and the computer would not boot. It complained
- about a hardware parity error in 0000:0000. I "un-swapped" the
- chips and it still would not work. My old CPU does boot but
- when I run its ROM debugger it gives me the same error at 0000:0000.
- I ran a sweep through all of RAM (on my old CPU) using RAMVIEW
- and found a couple of possibly bad memory chips but they were up
- in 5395:0a78 and 8392:8568.
- My concern then is this: Could there be a memory conflict between
- the old and the new boards? In which case (and in any case) does
- someone out there know what the DIP switch and jumper settings are
- for this board? Also, could the jump in speed affect the older
- (and slower) RAM on my Memory board? The chips are numbered
- MT4264-15 for the US made ones, M3764-15RS from OKI Japan, and
- SN74LS368AN for the TI chips from Malaysia. There are a lot of
- them (16k chips, remember them?)
- The board is a CPU/MEMORY BOARD 85-3162-01 111485 and the BIOS
- is dated (c) 1984.
-
- My other acquisition is a CGA/floppy disk controller card. The
- CGA works well enough for me to see the error message that something
- is wrong at the F000:0000 block of RAM. Again, there are a lot
- of DIP switches so something might be mis-switched. The
- thing that gets me is that F000 is dedicated to ROM (according to
- my copy of Norton's Programmer's Guide) so the new card should
- not affect RAM check in that area at all. The guy I got it from
- says he didn't have any problem with booting up. The problem
- was that the disk controller would not work. The card is simply
- labeled ZENITH DATA SYSTEMS COLOR VIDEO/FLOPPY BOARD and the
- last date I see on it is 1986. If I can get it working, I can
- take out the other two boards (keeping them as backups, of course)
- and have a free slot!
-
- If anyone can offer any suggestions or meanings behind DIP
- and jumper settings, I would love to hear from you.
-
- Andrew Dalke
- dalke@uxa.cso.uiuc.edu
- .plan
- --
- Andrew
- dalke@uiuc.edu
-