Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sdd.hp.com!wuarchive!emory!gatech!uflorida!reef.cis.ufl.edu!jdb From: jdb@reef.cis.ufl.edu (Brian K. W. Hook) Newsgroups: comp.sys.ibm.pc.hardware Subject: Re: DTK motherboards Message-ID: <26778@uflorida.cis.ufl.EDU> Date: 8 Feb 91 00:32:54 GMT References: <1991Feb7.012557.13458@yrloc.ipsa.reuter.COM> <26767@uflorida.cis.ufl.EDU> <2274@travis.csd.harris.com> Sender: news@uflorida.cis.ufl.EDU Distribution: na Organization: UF CIS Dept. Lines: 82 In article <2274@travis.csd.harris.com> leoh@hardy.hdw.csd.harris.com (Leo Hinds) writes: >In article <26767@uflorida.cis.ufl.EDU> jdb@swamp.cis.ufl.edu (Brian K. W. Hook) writes: >>DTK bus caused WD-1006SRV to fry, taking the other peripheral boards with >>it. This was attributed to the WD not being able to sync with the bus. >>The WD worked fine in a VIP machine. > >Please explain this one in technical terms ... what you describe does not >make sense. Well, as far as I can remember, here was the sequence of events: 1. We had a DTK 286-16 w/ 1MB of RAM and a 1:1 MFM 16-bit controller and a Seagate ST251-1 40MB MFM drive. This machine was functioning perfectly the time we had it (about 1 month at that time). The user who was using the machine requested that we upgrade the system so that she could store larger Ventura files. This required moving to an RLL controller and drive that we had in stock. 2. We took the computer, backed it up on Bernoulli, then removed the current controller (non-descript, generic I belive....possibly DTC?) and hard drive. We installed the new ST277R-1 and a WD1006SRV2 (Not sure exact model....16-bit RLL 1:1 controller) that we had taken from a VIP 286-16 which we in turn had given the old controller and drive. We checked jumpers, wires, etc. and were expecting a routine swap out and when we turned on the motherboard, it just plain died. No fanfare, smoke, or anything. The fan came on, but there was no video and the hard drive wasn't spinning. Machine gave no post-mortem beeps. 3. We double checked all connections then inserted a brand new WD1006SRV2 in its stead. Same thing. We then tried the old controller and drive. Etc. etc. etc. Same thing. MB was DEAD. 4. Called tech support at Southern Electronic Distributors (our DTK supplier). They informed us that "well, um, we think there might have been some timing problems on our motherboards where early cards such as the WD you're using caused system failures. We'll give you an RMA number and send you some other new motherboards. This applies only to the 286-16, 286-20, and the 386-20 that uses SIPPS." We ended up shipping the dead board and five other good boards back for the 'new and improved' models. Of course, SED was not particularly willing to replace the now dead I/O card, EGA card, and bus mouse card. Luckily hard drive was still functional. 5. Finally, we got the new motherboards, we reinstalled them, and everything worked just fine - until.... 6. We replaced a Paradise EGA480 with a generic Paradise chipset based EGA card. The only visible difference was that the generic used 120ns ram chips and the Paradise used 100ns. We installed this in a DTK 286-16 or possible 386-20, can't remember. We got a nice blue band about 3/4" wide on the left hand side of the monitor. We swapped monitors, nothing worked. We then swapped back the old card. Worked. We then put the old card back. Worked fine. We tried the generic card in another system. Worked fine. Basically, we had a system that did not like this one video card, which other PCs had no problem. We called SED once again. SED this time stated that we were getting the blue bands because the memory chips were being attempted to be overloaded on screen refreshes. Ie. the card's RAM was too slow for the DTK's bus. We asked if the bus could be slowed down to 8mhz, and they said "no." 7. Finally, let me point out that when I worked as a technician at the University of Florida Law School (where all this happened) we had between a 15 and 20% return rate on equipment from SED in particular. And of that, about 50% was DTK related components. Whew! I hope this was concise enough! One last thing....DTK does not give direct end user support much like COMPAQ and IBM. This is a serious problem, since the DTK support will only be as good as the company you purchased the DTK equipment from. SED was helpful and knowledgable, and most of the problems were related to the DTK. Some people who buy from "Mom and Pop" mail order houses will get into a lot of hot water when they try and get their defunct equipment repaired. Hope this helped, Brian PS DTK may have improved since last summer, but I'm not taking any chances. I have a Micronics, BIOS flaws and all, and am damned happy about it! :)