HWPB01.THD --- Copyright 1987 by Phil Wheeler An original compilation of Compuserve Model 100 Forum messages for use by Forum members only. HWPB = HardWare ProBlem. This file is a collection of messages about a specific problem report related to the RS-232 port distorting characters -- and some of the diagnostic analyses that were offered. For reference, in case it comes up again. The final outcome will be added -- when and if reported. Message range: 158067 to 158231 Dates: 10/11/87 to 10/14/87 Sb: #hardware problem?? Fm: Ronn Lucas 75665,1201 To: all Having a strange problem here. Trying to log in to CompuServe with the Model 100, and when typing the User ID, the comma comes back as a $. If I put the machine in half duplex, I see ",$", so it would appear the M100 at least _thinks_ it's sending out a comma. This machine has had a PG Design chip providing an additional 7 banks of 32K, but I removed the chip and flipped the switch on the underside of the computer in an attempt to reinitialize the memory. I also went into Basic and typed "clear 256, MAXRAM". But the comma continues to echo as $, and there are some other strangenesses as well when I use the graph key, like capital letters coming from the top (numberic) row of the keyboard. It seems like I need to totally clear the memory, but I thought I did that. Is there something I'm not doing? Or does this sound like a hardware problem? Fm: Tony Anderson 76703,4062 To: Ronn Lucas 75665,1201 Sounds more like you've got a problem in the keyboard. Some of the characters are doing funny things. Perhaps you've got a hairline crack in the circuit board someplace; or a thingamajig has crapped out, and needs to be replaced. Do these same problems occur when entering text into a TEXT file? Or just in TELCOM? -- Weird! Fm: Phil Wheeler 71266,125 To: Ronn Lucas 75665,1201 As Tony asks -- only in Telcom (sounds that way if half duplex gives the result you noted)? AND -- only on CIS? Try another service (e.g. BBS) and see what happens. If this happens only AFTER logon, it could be your CIS DEFALT setting (don't know how, tho). If on CIS only, try another node -it could be that your local node is messed up in some way. I have in the recesses of my mind the faint memory of a similar report a long time ago. But I cannot recall the outcome -- or who it was. Fm: Phil Wheeler 71266,125 To: Ronn Lucas 75665,1201 comma and $ differ by 8 -- and only in the fourth bit of the code (see M100 manual). Now, what are some of the other mappings you are getting, Ronn? A difference of 8 is usually significant in a computer, since it can come from a single bit being lost. See if this "4th bit" thing (0 when it should be one) is a pattern. May be in the UART conversion from parllel to serial data. Fm: Ronn Lucas 75665,1201 To: Phil Wheeler 71266,125 Thanks for the response, Phil. The only other weird things happen only when I use the graph key. By itself, the alpha keyboard works fine. And if I type the PPN into a text file and copy it, then dial up CIS and logon, if I paste the user ID I still get the $ coming back. The PG Design chip uses a program with a bunch of POKEs in it to bank switch. Do those all get restored to their "normal" values when you flip the switch on the underside of the Model 100? Or do I have to do something else to get rid of that program? The stat _is_ set to M7I1E, but I'll try hooking the Model 100 to a friend's Mac, and see what gets transmitted. The problem doesn't happen _after_ logon; I never get past the 1st half of the PPN (ie past the comma) on anyone's account. And this account works fine from the Mac. It never occurred to me to try another service (he says slapping himself on the forehead); I don't have the M100 at hand, but will check that out soon. Fm: Ronn Lucas 75665,1201 To: Tony Anderson 76703,4062 Thanks, Tony. I believe you're right about a crack in the keyboard (though see my message to Phil). Strangely, this Model 100 (my 2nd) was one of the last they made before introducing the 102. I would have expected hardware problems with the much older one first. The other one's not here, or I'd obviously be trying Telcom in that beast as well. Not only don't I have a problem with the comma in TEXT files, but I even typed the PPN into a file and copied it, went into TELCOM and called up CIS, and at the ID prompt tried doing a paste. No dice. The comma still came back as a $. I wonder if that by itself indicates software rather than hardware being at fault? My guess is that I've got the remains of a machine language program (for bank switching with the PG Design chip) still lingering in the memory. All those POKEs scare me. Do they all disappear when you shut off the switch on the back, or is some more voodoo required? Fm: Tony Anderson 76703,4062 To: Ronn Lucas 75665,1201 I doubt that any remains of a ML program would cause the problem you describe, since to do so, your output to the COM routine would have to be looping through the ML routine all the time, and the routine would have to set up to change commas to dollar signs.... and have no other effect. It'd have to be a pretty specifically written bit of code to work that way without creating any cold starts. If you turn off the memory switch on the bottom of the case, and leave it off overnight, the RAM chip power should drain away, and when you turn on the switch again the next day, your memory should be in the same pristine, clean, empty state it was in when you bought the machine. Nothing could be "hanging around, hooked into TELCOM" after that. It's referred to as a "Arctic Start" - the coldest of the cold. You lose EVERYTHING! After reading Phil's analysis, the missing or changed bit, that seems to be the most logical source of the problem That might mean a defective chip somewhere in the chain... I haven't the foggiest idea of which one, though. Does the comma get changed with direct keyboard input, too? If from both the autosend feature (from the RAM file), or the Paste Buffer, AND the keyboard, then I'd suspect something in the UART or external to the machine. But if the keyboard input works OK, then the problem has to be internal. Fm: Phil Wheeler 71266,125 To: Ronn Lucas 75665,1201 Peculiar stuff! I take it that it only happens on TECOM, not TEXT -- tho I don't think you have confirmed that. Tieing to another machine and seeing what happens is important. The fact that you get the same thing with a text file sent out with PPN says it is not the keyboard -- no surprise, since half duplex shows the lcomma as one of the chars. Would be interesting to know if half-duplex echo goes thru the uart. PG RAM stuff should have zero effect, I believe -- and definitely none after a cold start. Fm: Phil Wheeler 71266,125 To: Ronn Lucas 75665,1201 If you have not done a complete memory purge overnite, that is the very first thing to try. I'm not optimistic re the gains -- but the price is right! Fm: Denny Thomas 76701,40 To: Ronn Lucas 75665,1201 That sounds suspiciously like the problem I had with my second M100 - I also bought it during the final closeout before the T102 was introduced. Mine wasn't just partially bad, it's telcom chip was gone completely, but I wonder if there is some correlation. Luckily, I sent it back the next day and got a newcould it be that the last units had some weak UART chips? Fm: Ronn Lucas 75665,1201 To: Denny Thomas 76701,40 Yea, it looks like the entire telcom chip in this one's bad as well. Hooked it up to the Mac today, and most of the keyboard is sending out characters other than what are on the keycaps. And not a comma in the bunch. We'll see what Radio Shack service has to say tomorrow. Fm: Ronn Lucas 75665,1201 To: Phil Wheeler 71266,125 The problem shows up only in Telcom. Hooked the Model 100 up to the Mac today, and most of the keyboard is sending out wrong characters. I'll take it in tomorrow, but it looks like the entire Telcom chip went down. Hope the repair costs less than a new laptop. Overnight memory purge was a good idea, but didn't change anything with the comma/$. I guess I didn't notice the problem with the PPN because the number row is mostly accurate, and I never got past where the comma should be to find any of the other problems. Fm: Ronn Lucas 75665,1201 To: Tony Anderson 76703,4062 See my messages to Phil and Denny. Looks like the entire Telcom chip went down. Thanks for your help tracking this down. Fm: Phil Wheeler 71266,125 To: Ronn Lucas 75665,1201 Numbers from 0 to 8 have bit 4 at 0 -- so they would be unaffected in my theory. Make that 0 to 7. But 8, 9 would give 0 and 1 -- still numbers, so you might not pick it up right away. It does sound like the UART (or something closely related). Past history suggests they may want to changeout the entire mother board -- while in this case it may be a single chip. If so (and the chip can be purchased as a part) you may wnat to look into alternate repair possibilites. On the otherhand, if you can give them a really good set of symptoms -- and point to the UART -- they may give the component-level repair a shot. Fm: Ronn Lucas 75665,1201 To: Phil Wheeler 71266,125 You're exactly right... 0-7 did come out normal, and 8 & 9 did give 0 & 1. I now better understand your previous message, and will definitely ask to have the UART (whatever that is) checked out. Fm: Tony Anderson 76703,4062 To: Ronn Lucas 75665,1201 Well, at least you have a better handle on the problem now, and can describe it in more detail to the service department. Good luck.