TRM900@PSUVM.BITNET (Tony R. Marasco) (03/27/89)
After 5 years of service (without ANY manufacturer service), I really think my TRS-80 Model IV is about to "bite the dust". I'd like to repair it, as long as the problem isn't too costly. This is what happens: After being used for about 1/2 hour in either Model III or IV mode, the screen gets large, the cassette switch (I guess it's a relay) clicks, and the machine resets. If I allow it to rest for about 2 minutes, it decides to run fine again. This just started to happen about 1-2 weeks ago... Does anyone have any idea as to what the problem might be? Should I get rid of it? Any help is greatly appreciated...
uhclem@trsvax.UUCP (04/01/89)
<> Sounds like your Model 4 has a "Tandy" power supply that is going bad. At one point in the manufacturing life of the Model 4, someone at the factory was using "Locktite" to secure a voltage-adgust pot. Great, but the solvent in that compound eventually eats the carbon out of the pot, causing wild voltage fluctuations after the machine has been on a while. Replace that power supply with a real "Aztec". Both types are clearly marked, but you can tell the difference by checking the switching transistor. If it is a TO3 can configuration, you have an Aztec. If it is mounted on a "stand-up" heatsink, you have a "Tandy" supply. These supplies can be obtained through National parts. They were also used in external primary hard disk drives. (65watt) <My opinion, and not that of my employer.> "Thank you, Uh Clem." Frank Durda IV @ <trsvax!uhclem> ...decvax!microsoft!trsvax!uhclem ...sys1!hal6000!trsvax!uhclem
wilso_d@cs.odu.edu (DeWitte Wilson) (04/01/89)
In article <77815TRM900@PSUVM> TRM900@PSUVM.BITNET (Tony R. Marasco) writes: >After being used for >about 1/2 hour in either Model III or IV mode, the screen gets large, >the cassette switch (I guess it's a relay) clicks, and the machine >resets. If I allow it to rest for about 2 minutes, it decides to run >fine again. This just started to happen about 1-2 weeks ago... > >Does anyone have any idea as to what the problem >might be? Should I get rid of it? Any help is greatly appreciated... I wouldn't get rid of it, but you might try checking out your power supply. Radio Shack would probably charge WAY too much to look at it, so if you can find someone locally (at a users group) that could look it over, it would be better. I had a similar problem about a week ago - the system kept booting, and Cassette basic was non existent. I finally traced it to the model 4 speaker connection, which SUDDENLY (??) decided to go bad - a few times plugging it in/unplugging it cleared up the problem. ...dewitte -- DeWitte Wilson <wilso_d@cs.odu.edu> Old Dominion University Sysop - The Mod III BBS 804-424-1215 [300=>2400] 8N1 "We are the keepers of the Sacred Words. Ni ... Peng ... and Neee ... Wom!"
gmadison@pnet02.cts.com (George Madison) (04/01/89)
TRM900@PSUVM.BITNET (Tony R. Marasco) writes: > >After being used for >about 1/2 hour in either Model III or IV mode, the screen gets large, >the cassette switch (I guess it's a relay) clicks, and the machine >resets. If I allow it to rest for about 2 minutes, it decides to run >fine again. This just started to happen about 1-2 weeks ago... > Sounds like a power supply problem; that's a noted weak point in a lot of Model 4's. What you want is an ASTEC 65w power supply; I was able to pick up a spare for $20 or so, though they may be more now. If you don't mind diddling the insides of your machine, you might look into this. If you *DO* mind, and your local Tandy tech center has a decent reputation, give them a try. If you're still happy with your 4 after 5 years, there's no reason to give up on it now for what seems to be a fairly easily fixed problem |George Madison, a/k/a George The Bear Cub, a/k/a Furr ** BEAR POWER **| |INET: gmadison@pnet02.cts.com 8-{)> ames!elroy!pnet02.cts.com!gmadison| |GEnie: GEORGE.M Arctophiles & Barbophiles Unite! PLink: BEARDLOVER| "He's the lonely fear of dying, and for some, of living too; He's your private nightmare pricking, he'd just love to turn the screw So stand as one defiant -- yes, and let your voices swell Stare that Beastie in the face and really give him Hell." --- "Beastie" by Jethro Tull