(c)1990 Golden Triangle, Inc. (c)1990 Wilson Van Alst All rights reserved. Fm: LOUIS SELF To: All My T-200's DataPac got it's memory scrambled. Out of the original 90 files only 44 are on the main menu now and about eight of those file names have been changed to portions of previous file contents, such as "his op.er". Some of the file names are invalid, such as ",177,1.94" (how's that for a file name?). Moving the cursor over one of those causes the 200 to beep endlessly until the RESET button is pressed. Also most of the files are scrambled, containing portions of other files. Any idea of what caused it? I had been using the 200 regularly from both battery and automobile adaptor, so the DataPac should have been charged. I did have it sitting in the car for a few hours at about 100 degrees (not in direct sunshine). - 0 - Fm: Paul Globman To: LOUIS SELF Louis - Sorry to hear about your Datapac scramble. It's hard to say what caused it, from here ... could be anything from a corrupt ML program sending improper data to an I/O port, to a bad call (improper address) into the ROM, which could have the same disasterous results. I recall a message from you about I/O port access to the unit... were you experimenting, or have any programs using those INP's or OUTs? I believe the calls to the Node ROM have been proven safe.... Paul - 0 - Fm: LOUIS SELF To: Paul Globman No, Paul, I wasn't experimenting with anything other than the standard ROM calls provided by Node. I think I have enough of a handle on the DataPac organization to not mess things up that way. What can you tell me about how the DataPac keeps track of its files? Here's some of what I have found out when I did an ASCII dump to my printer. I found that a file's name is in ASCII as the first 8 chracters of the DataPac sector on which the file begins. The 9th and 10th bytes represent the length of the file. There must be someplace where next-file information is kept, in addition to where the next-sector information is kept with a file that occupies more than one sector. - 0 - Fm: RANDY HESS To: LOUIS SELF Loius, One other culprit may be the "100' +" temperatures you subjected the unit too. If you examine the "internal leakage(self-discharge)" characteristics of NiCad or Lithium batteries you quickly see that the life-cycle literally "falls off a cliff" when their internal temps exceed 85-90' F. Since any mass has whats known as "thermal inertia" we can sometimes get away with using our machines for a while in hot weather because all the parts don't really become INTERNALLY heated to dangerous levels but if you really "cooked" your machine, then I wouldn't be a bit surprised if the battery levels in the Node or M100 reached levels too low to function. In the manual for the new Node RAMPAC the "lifetime" lithium battery used to keep the unit alive has its life reduced from 9 yrs to 3 years by simply increasing the operating temp to 95! Also other on board components begin to exhibit funny characterstics when running at high temperatures: and the same thermal inertia which lets us run these units occasionally in hotter environments works the other way after you heat up all the parts to 100+! It takes a while for everything to cool down. Not for nothing are many of the new supercomputers cooled with liquid nitrogen! Keep Cool! - 0 - Fm: LOUIS SELF To: RANDY HESS Heat sounds the most likely of the ideas here so far. The Node instructions say that the the nicads will last 3 months warm and 8 months cold. I wander how warm that means? Do nicads give discharge memory problems in memory backup applications? Living in Phoenix, as I do and using my 200 on camp outs and trips to the lake, guess it is time to get out the ice chest and keep the 200 with frozen gell when not in use. - 0 - Fm: Wilson Van Alst To: LOUIS SELF I wonder about the wisdom of using the auto adapter. If it's one especially designed with filtering for computers, you're probably OK. But if you use a $5 unit that just changes 12v to 6v, it won't do much to keep AC "spikes" out of the current -- and they can play havoc with low-power CMOS computer chips. - 0 - Fm: LOUIS SELF To: Wilson Van Alst I have been assuming that the 200 has some sort of voltage regulator built in. Correct? The little 110v adaptor that Radio Shack sells for the 102/200's puts out well over 6 volts. My auto adaptor is the little $13 Radio Shack cat #273-1650. Do you think it would be a good idea to make my own regulator? About all it would take, I suppose, would be a 7806 to regulate the 12v down to 6v. - 0 - Fm: Wilson Van Alst To: LOUIS SELF The T200 does have a fairly sophisticated voltage regulator -- one that converts DC to high-frequency AC, spits it though a transformer, and bridges everything back to DC again. With a little bit of negative feedback, the circuit "knows" how much DC current to draw on the input side to maintain a constant output voltage. I don't know how good this circuitry is, however, at protecting against AC ripples and spikes. Tandy cared enough about this to include a simple bridging capacitor (2200mf @10V electrolytic) to filter its AC adapter for these computers -- while it sells unfiltered adapters for most 6v items like cassette recorders. I'd recommend adding at least that much protection to your auto adapter. Actually, I'd recommend substantially more since I'm very mistrusting of auto electricity; but that's a personal prejudice. There is one other item: I don't know whether the Node takes any of its operating power from the computer. If it does, you'd have to ask where the "tap" is made -- on the input or output side of the computer's voltage regulation circuit? In other words, it's possible that your T200 is getting a nice smooth electron stream, while the Node is sailing in rougher waters. (This seems unlikely, but you never know till you ask.) - 0 - Fm: LOUIS SELF To: Wilson Van Alst Thanks for the education on power supplies, Wilson. You said that you would recommend substantially more protection for the 200 operating from the cigarette lighter. Would a 7806 regulator work directly from the 12 volts (13.7 with engine operating)? Where does the Node get its power from the computer? From the systems bus, of course, but only when the computer is turned on. The question is, does the bus get its power pre or post regulation! Who knows? - 0 - Fm: Wilson Van Alst To: LOUIS SELF The 7806, to me, would be better than Tandy's simple resistorized auto converter (assuming that's what you have). I would still want to filter the output with at least a good-size capacitor, and preferably some inductance as well. You won't need this kind of protection if you follow Stan's advice and use the computer only when the car =isn't= running. - 0 - Fm: Stan Wong To: LOUIS SELF If your car engine is not running, you can use the 12V power to run the T200 (with the appropriate 12V-6V converter). I wouldn't recommend doing it with the engine running. I solved the problem by using my camcorder battery. It has the standard cigar-lighter socket and puts out 12V. I simply use that battery when I need additional power while on the move. - 0 - Fm: LOUIS SELF To: Stan Wong You have an interesting solution to the power problem, Stan. You said you would not recommend using the cigarette lighter with the engine running. Do you know if a 7806 regulator would protect the system? - 0 - Fm: Stan Wong To: LOUIS SELF I'm not familiar with the 7806 regulator (or any other for that matter). Car power systems are too glitchy when running that it's not worth the risk for me. The camcorder battery solves my problem although it adds additional space and weight. Since I already own the battery, the incremental cost of using it was zero. Otherwise I would use something like a lantern battery. One of those should power a T200 for a long, long time. - 0 - Fm: Tony Anderson To: Stan Wong One user, some time ago, reported 300 hours use on a 6-volt lantern battery. I suspect he probably used the alkaline model, which costs about twice as much as a set of AA alkalines, but still, 15 times the use for twice the money isn't bad. A "standard" lantern battery is (or has been) available at K-Mart for $2.39, which is less than a set of AA's, and would certainly power the portable for at least a hundred hours or so... my estimate. - 0 - Fm: RANDY HESS To: Tony Anderson ..and a lantern battery is not really a great deal larger than the AC adapter: I've been using them for years. Good advice! (and with two plugs I can run both the TDD and the 200 from the same "clean" power.) - 0 - Fm: RANDY HESS To: LOUIS SELF In addition to the 50-100 mfd cap/inductance filter Van suggested you should probably include a non "electrolytic" .1-1mfd cap. in parallel with the larger cap. because electrolytic caps are notoriously poor filters of just the kind of high-freq. energy that you want to be sure to remove. I would suggest putting filters in "front" of any regulating device as well as on the output circuit. Auto electrical systems are famous for some horrendous (30-40 vpp) Radio Frequency transients that could well "fry" the 7806 junction if not removed! Good luck (and why not write up the filter/regulator module when done?!) - 0 - Starting message #: 25526 Starting date: 30-May-90 21:15:12 Participants: LOUIS SELF 74076,1273 Paul Globman 72227,1661 RANDY HESS 73267,552 Wilson Van Alst 76576,2735 Stan Wong 70346,1267 Tony Anderson 76703,4062