wsinkees@wsinti01.info.win.tue.nl (Kees Huizing) (08/13/90)
I hope this is the right newsgroup for this question, since I don't read it usually. Otherwise, please point me (by e-mail) to the right group. Now for the problem. My father in law has an old TRS-80 Model I with a expansion box with extra memory, floppy connector, etc. He still uses it, because he likes the computer, although connections are bad and things often fail several times before they work properly, etc. Recently, a more serious problem occurred: the monitor doesn't work anymore. First, it showed a lot of >-signs and "encrypted" text, but he knew the questions, like "HOW MANY FILES?" (in Basic) and just typed the answers, and the program worked. The output of the program got better and better, until suddenly, everything went blank and didn't come back anymore. Now, the monitor shows nothing, just nothing. I am not sure that this is exactly how it went (I wasn't there), but the result is quite definite. My questions to you are: 1. Do you have any idea what could be wrong? 2. How can we find out what the failing component is (we're not very technical and we are quite disconnected from TRS-80 hobbyists)? 3. If it is the monitor, can we connect another monitor to the computer, for testing or replacement? Is there some kind of interface name with which we can go to a dealer and ask: "What is your cheapest <whatever> monitor?" 4. Does it make sense to go to a Tandy shop and ask for advise, or are the guys there too young to know about this machine? Thank you very, very much, if you want to think about this. I will read this group for some weeks, so you can post replies if you want, but e-mail is welcome. -- Kees Huizing - Eindhoven Univ of Techn - Dept Math & Comp Sc - The Netherlands DOMAIN: wsinkees@win.tue.nl BITNET: wsdckeesh@heitue5 FAX: +31-40-436685
ttak@uhura.cc.rochester.edu (Timothy Takahashi) (08/13/90)
In article <1335@svin02.info.win.tue.nl> wsinkees@wsinti01.info.win.tue.nl (Kees Huizing) writes: >My father in law has an old TRS-80 Model I with a expansion box with >extra memory, floppy connector, etc. He still uses it, because he >likes the computer, although connections are bad and things often fail >several times before they work properly, etc. Recently, a more serious >problem occurred: the monitor doesn't work anymore. First, it showed >a lot of >-signs and "encrypted" text, but he knew the questions, like >"HOW MANY FILES?" (in Basic) and just typed the answers, and the >program worked. The output of the program got better and better, until > >1. Do you have any idea what could be wrong? Sounds like a problem in the video circuitry of the keyboard/cpu unit. A failed RAM chip in the video (a 2102 I believe). If the unit has had a lower case modification on it, there is a lot of extra wiring on the cpu unit. Also, the character generator chip could have fallen off! (I've seen it) >3. If it is the monitor, can we connect another monitor to the computer, >for testing or replacement? I doubt that it is the screen that has failed. >4. Does it make sense to go to a Tandy shop and ask for advise, or are the >guys there too young to know about this machine? Try. I think there are a few Model I parts still kicking around. >Kees Huizing - Eindhoven Univ of Techn - Dept Math & Comp Sc - The Netherlands Tim Takahashi ttak@uhura.cc.rochester.edu
fzsitvay@techbook.com (Frank Zsitvay) (08/18/90)
In article <1335@svin02.info.win.tue.nl> wsinkees@wsinti01.info.win.tue.nl (Kees Huizing) writes: >My father in law has an old TRS-80 Model I with a expansion box with >extra memory, floppy connector, etc. He still uses it, because he >likes the computer, although connections are bad and things often fail >several times before they work properly, etc. Recently, a more serious >problem occurred: the monitor doesn't work anymore. First, it showed >a lot of >-signs and "encrypted" text, but he knew the questions, like >"HOW MANY FILES?" (in Basic) and just typed the answers, and the >program worked. The output of the program got better and better, until >suddenly, everything went blank and didn't come back anymore. Now, the >monitor shows nothing, just nothing. I am not sure that this is >exactly how it went (I wasn't there), but the result is quite >definite. My questions to you are: > >1. Do you have any idea what could be wrong? Radio shack didn't use a dedicated video chip on the model 1, they opted for their own design using discrete logic chips. a bad gate in just about any of those chips can cause the problem you mention, especially if the problem is temperature related. >2. How can we find out what the failing component is (we're not very >technical and we are quite disconnected from TRS-80 hobbyists)? If you can get it, the cooling spray available at radio shack and other electronic supply houses could be of help, to locate the particular chip. this is assuming the problem is related to temperature. aside from that, without some advanced electronic test equipment, it's virtually impossible. >3. If it is the monitor, can we connect another monitor to the computer, >for testing or replacement? Is there some kind of interface name with which >we can go to a dealer and ask: "What is your cheapest <whatever> monitor?" It doesn't sound like a problem with the monitor itself... >4. Does it make sense to go to a Tandy shop and ask for advise, or are the >guys there too young to know about this machine? In the states, often the guys at the service center are too young. I can't get parts for my model 2 machines anymore, and radio shack used to be very good about supporting their early machines, although their service personell often had refried beans for brains. But in the netherlands, who knows. You have nothing to lose taking it in to have them give you an answer as to whether they can work on it or not. but be forewarned, they might laugh in your face (like they did at me) and tell you to buy a 1000 instead. Don't lose hope, because you can often find model 1s and 3s real cheap if you know where to look. and, if your local university has a computer science department (one that teaches hardware design) you might be able to get one of their students to try repairing it. it's a rather simple design. > > >Thank you very, very much, if you want to think about this. I will read >this group for some weeks, so you can post replies if you want, but e-mail >is welcome. >-- >Kees Huizing - Eindhoven Univ of Techn - Dept Math & Comp Sc - The Netherlands >DOMAIN: wsinkees@win.tue.nl BITNET: wsdckeesh@heitue5 FAX: +31-40-436685 -- fzsitvay@techbook.COM - one of these days i'll get it right... Version 2 of anything is usually the version that works.