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Model 4 Power Supply issues...

A

ardsleytank

Experienced Member
Joined
Nov 15, 2015
Messages
282
Location
Tennessee
Well, I guess I never learn.

Just got back from a trip and on the way I brought some "rescues" with me. Okay, the Model 4 I got off Craigslist but who's taking notes? (In case you're curious, the other 'Rescues are an IBM Aptiva E275 w/monitor and an Imac G3. Got those from a nice lady.)

Any way, brought home a nice Model 4. It was working before I picked it up, but the owner said he powered it up that morning and left it for about 15 minutes came back and it had shut off. So I got it for a great price, much less than I was going to pay previously, and took the old girl home. So I took her apart and here's the situation. The power supply is clicking when I turn it on, and the drives flicker with every click. I reflowed the header pins, but no luck. The old paperfilter caps look good, no cracks or buldging. It's a non- gate array with a Tandy power supply.

Maybe you guys can help me. (Also, the keyboard is filthy. How does one take it apart?)

Thanks,
Peter
 
Woohoo! Fixed it. The power supply was grounding itself on the case. (By grounding itself, I mean in a place other than it should. ) I isolated the mounting screws and get Preston, she's off and working like New! For those who are interested she's a TRS-80 Model 4 Non-Gate Array with cluster keyboard and green screen. Serial No. 007041. Built March 6th, 1984.
 
Yeah, I'm a Model 4 fan now for sure. That sharp display... :D. This is a 64k model though. What's the advantage to having more ram in a machine like this? Ridiculously long BASIC programs? ;)
 
Favorite is DDuty that lets you run two separate memory spaces and a third mini space. Other than that, with FreHD and other things, the RAM disk feature isn't quite there.

Some Word processors also can use it.

You can get a GAL from Ian, and buy some ram online if you are patient.
 
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