car@trux.UUCP (Chris Rende) (06/08/91)
I'll be opening the case of my 3b1 in the near future. While I've got it open, what all should I do? Here is a list of what I have planned: - Replace the fan. (It's been doing the fast/slow/fast/slow act. This is my main reason for opening the case). - Clean the dust out. What markings or numbers should I look for that may be of future interest? I have a spare WD2010 HD controller chip that I got real cheap. Are there any advantages to installing the WD2010 if I don't plan to use more than 1024 cylinders or more than 1 hard disk? car. -- Christopher A. Rende Central Cartage (Nixdorf/Pyramid/SysVR2/BSD4.3) uunet!edsews!rphroy!trux!car Multics,DTSS,Unix,Shortwave,Scanners,UnixPC/3B1 car@trux.mi.org Minix 1.2,PC/XT,Mac+,TRS-80 Model I,1802 ELF trux!ramecs!car "I don't ever remember forgetting anything." - Chris Rende
thad@public.BTR.COM (Thaddeus P. Floryan) (06/08/91)
In article <550@trux.UUCP> car@trux.UUCP (Chris Rende) writes: >I'll be opening the case of my 3b1 in the near future. >[...] >What markings or numbers should I look for that may be of future interest? >[...] The board "schematic" number (in copper) near the left rear corner is quite useful when referencing one of the three sets of schematics in the Reference Manual. Often the copper number is obscured by a white sticker bearing a different number. BOTH sets of numbers "almost" uniquely identify your machine. Peel the white sticker off and reapply it flanking the copper number. The copper board number will (usually) be one of 60-00222-00, 60-00225-00 or 60-00230-00. If yours is 60-00216-00 you have my sympathy (the connector to the floppy drive may be pin-for-pin reversed from that found on all other motherboards, and you probably have the daughterboard above the motherboard). The white paper sticker will bear a printed number something like "60-00237". The OTHER "number" to write down for future reference is the "REV.n" value on the white sticker normally found near the volume control sliding pot; this will be something like "REV.C", "REV.F", "REV.J", etc. The combination of the two sets of reference designators seems to uniquely identify all 3B1 systems I've seen. And note that a "REV.C" on a "225" board is NOT the same as a "REV.C" on a "230" board. And, before you ask, I have NOT been able to determine precisely what each "REV.n" represents and I doubt that information still exists even at CT (now UNISYS/NCG). >I have a spare WD2010 HD controller chip that I got real cheap. Are there >any advantages to installing the WD2010 if I don't plan to use more than >1024 cylinders or more than 1 hard disk? >[...] If your system is one that DOESN'T have the "DRUN Patch" then putting the WD2010 in your system will cause you a LOT of grief. From my observations on MANY systems, it's not always obvious whether the patch exists on one's system; some factory runs implemented the patch along the lines of what I described in my posting last December, and some runs had the patch integrated into (presumably) new motherboard layouts where the legs of the 74123 chip are NOT sticking up in the air. If the resistor at R63 has the color code bands, then the presence of 4.75K 1% means the patch is already applied (the value of 6.81K 1% means you have the old data separator circuit which will NOT function properly with a WD2010); if the resistor is the RN05 type (no color bands) then you probably won't be able to read the value and you'll either have to remove it (to read the value) or forget the whole thing. The ABSENCE of a capacitor at C252 is also a good clue one's motherboard has the DRUN patch already applied. On other CT-built systems, the WD2010 was used from the factory and the CTIX kernel ran the chip in ECC mode (usually) and a step rate value of 14 (vs. the 0 used in the 3B1/UNIXPC). The difference is QUITE noticeable even to me (with my bad hearing): a Maxtor will calibrate nearly instantly with a musical "phweeeet" sound contrasted with the same disk calibrating with a "ehhhhhhh..." sound on the 3B1. I've observed a greater than 6:1 performance difference on disk I/O (but that could also be due to the 68020, but ... ). There was a thread last year about altering the step rate with a WD2010 on the 3B1 but I don't recall if any conclusive evidence appeared either way. As long as your system will be open, you might want to consider replacing the battery before the original one dies. A circular battery holder and a 3V lithium battery (about the size of a quarter) should cost no more than $2.50 total, and will make replacement during the year 2001 easier (the new battery "should" last 10 years :-). Thad Floryan [ thad@btr.com (OR) {decwrl, mips, fernwood}!btr!thad ]
ignatz@wam.umd.edu (Mark J. Sienkiewicz) (06/09/91)
In article <550@trux.UUCP> car@trux.UUCP (Chris Rende) writes: >I'll be opening the case of my 3b1 in the near future. > >While I've got it open, what all should I do? > When I went to take the cover off mine, i discovered that there are 3 ridges that catch when you try to lift the top off. These are on the inside of the plastic cover, just under where the keyboard sits. | <<monitor above here>> | <<keyboard here>>| | --------------- | fan blows out here | <- ridges on this surface | | | If you take a pocket knife and carve those ridges off, the cover will be LOTS easier to get off next time. The first time I took the cover off, I had a lot of trouble trying to 1) lift the cover with attached monitor, while also 2) trying to pry all three of these ridges away from the metal case. Scraping them away doesn't make the cover any less secure. --- If you are savvy about such things, you might want to change your floppy drive for either a 3.5" drive or a 96 tpi drive. You can then make 800K disks instead of 400K disks. I took my floppy drive out of the cabinet and installed longer cables for it. I ran the cables out through where the left fan would have been. To this day, I have a 48 tpi and a 96 tpi drive sitting next to my machine waiting for "one of these days" when they will get mounted in a real box. I swap them back and forth, using the 48tpi drive for compatibility (e.g. distribution disks, msdos files) and the 96 tpi drive for everything else. --- Have fun. Mark. ignatz@avw.umd.edu