TRS-80 model I questions

[Atariman]

I purchased a TRS-80 model I computer two summers ago at a garage sale and have been wondering a few things about it. First, this appears to be an upgraded system (level II w/16k) but it has a switch on the front. When I flipped the switch, it would garble everything on the monitor - and return it to normal text afterwards. Any clue as to what this might be for?

 

The expansion interface that I received with it also seems to have been upgraded -

on the webpage http://skylane.kjsl.com/trs80/model1info.html it shows a picture of a board that could be added on to let the TRS-80 use double-density floppies. The board that is attached to the expansion is identical to the one found on the website listed above.

 

I have three floppy drives (I assume all work - I used two of them when I was playing around with it.)

 

The horizontal hold seems to be a little screwy as it needs to be adjusted every 5 minutes or so. The big problem is that the keyboard (and I mean THE keyboard, not the TRS-80 computer itself) seems to have a bit of a problem. When I first turn it on, it spits out a few letters/numbers (can't remember which) and has the flashing prompt... I don't remember if I can actually type anything after that (if I could, I wouldn't be able to use those particular characters that were initially displayed).

 

I'm asking these questions because I'm wondering if this thing is worth selling - anyone who knows me knows that I HATE to sell stuff (especially stuff that is semi-rare) but I'm trying to save up for an engagement ring... So any information (on repair or the rarity/function of these features are) would be greatly appreciated!

 

EDIT: also forgot to mention that this thing has the gold connectors soldered onto it along with the buffered expansion cable - I read somewhere (possibly on the website listed) that this was meant to give the expansion interface a more reliable connection with the TRS-80? I have yet to actually see a buffered expansion cable anywhere on the internet (although I admit I don't recall actually looking around too much)

Edited September 7, 2005 by atariman

[Clint Thompson]

Wow... sounds like a fun system to tinker with. I remember reading a fan site (of TRS80's) that the Model I gives out Super-hella Radio Interference! (I'd turn it on just for that reason!)

 

I remember back in the days with my Model III when I turned it on the TV picture would get snowy and my parents would start bitching. (so I couldn't use it when they were watching TV) sad because that's ALL THEY EVER DID!

 

Look on eBay for selling prices... it'd probably go for a nice penny if in very good condition physically. Monitor doesn't sound like a big problem... keyboard sounds iffy... the whole setup sounds interesting though!

[Stingray]

My TRS-80 screwed up the TV reception in my bedroom, because that TV had rabbit ears (those are TV antennas, kids). Didn't mess up the TV in the living room because it had cable.

 

-S

[Famicoman]

Mine doesn't even work. I turn it on, and there are a whole bunch of blocks.

[Zonie]

My buddy had one back in 7th grade. I was so amazed by that thing. He kept the power supply on the table top (used a card table) behind the tape recorder (Data drive for you kiddies). It messed up several tapes before he figured that out.

 

I used to drool over the model II in the catalogs.

 

We used to play "pillbox" on it for hours.

 

I had another friend who's dad had one with the matching furniture.

[JB]

Mine doesn't even work. I turn it on, and there are a whole bunch of blocks.

927720[/snapback]

A TRaSh-80!

[Clint Thompson]

Mine doesn't even work. I turn it on, and there are a whole bunch of blocks.

927720[/snapback]

 

What model do you have?

 

I see a TRS-80 Model 1 (non working) for $59 on eBay right now and no bids....

[Famicoman]

Mines a model 2

[Bruce Tomlin]

I purchased a TRS-80 model I computer two summers ago at a garage sale and have been wondering a few things about it.  First, this appears to be an upgraded system (level II w/16k) but it has a switch on the front.  When I flipped the switch, it would garble everything on the monitor - and return it to normal text afterwards.  Any clue as to what this might be for?

It's for a non-standard lowercase mod. The ROM wrote alpha characters from 40-7F hex as 00-1F hex, which worked fine with the 7-bit video RAM, but not when the extra bit was added.

 

The expansion interface that I received with it also seems to have been upgraded -

on the webpage http://skylane.kjsl.com/trs80/model1info.html it shows a picture of a board that could be added on to let the TRS-80 use double-density floppies.  The board that is attached to the expansion is identical to the one found on the website listed above.

Yep, it's a double-density mod. The Percom was the "standard" mod, and the Radio Shack version was esentially the same but with the control ports changed for no good reason. They both took the old single-density controller chip and switched between it and the double-density chip with a control port.

 

I'm pretty sure that if you knew what you were doing, you could write mixed-density tracks, with some sectors in single density and some in double-density. This wasn't done for copy protection, but for dual booting between the Model I and the Model III.

 

I have three floppy drives (I assume all work - I used two of them when I was playing around with it.)

They will probably need the motor speed adjusted. All old full-height drives, and a few half-height drives used belt drive with a block potentiometer for speed control. There are tach marks on the hub for this reason. I've found that light from a plain old light bulb was good enough.

 

My TRS-80 screwed up the TV reception in my bedroom, because that TV had rabbit ears (those are TV antennas, kids). Didn't mess up the TV in the living room because it had cable.

I had to turn mine off whenever the family wanted to watch channel 12.