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TRS-80 Questions


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#1 Tempest OFFLINE  

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Posted Mon May 24, 2010 8:24 AM

Since my Model III seems to be dead, I'm in the market for a new TRS-80. My question is, which is the best model to get? I know there are four different models, but I'm not sure how compatible they all are. The only thing I remember is that the model II isn't compatible with any of the others.

So that leaves the model 1, III, and 4. The III and 4 are the most attractive to me since they're an 'all in one' type thing, although the huge kludge that is the model 1 (with monitor, expander, and disk drives) is amusing. I'm interested in only playing games, so I think that leaves the III and 4 since I think there are some games that won't play on the 1.

Any suggestions? Also what are the common issues these things have? I see a lot of people saying that they couldn't get a ready prompt or that the screen seems to display garbage (or nothing at all). Are there some keys you need to press to get a ready prompt or does it automatically come up when you turn the machine on?

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#2 save2600 OFFLINE  

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Posted Mon May 24, 2010 8:31 AM

I recently brought 2 Model III's back to life. Mirage has one of 'em. 1st thing I'd check (I didn't read the other thread in its entirety) is to open her up and re-seat ALL of the socketed chips - especially the Z80 CPU. I'd be willing to bet that'll do the trick. Not uncommon to see oxidation on 'em as people simply threw them 'wherever' out of sight, out of mind. When you first turn on a Model III and assuming the disk drive and controller card work, the drive will spin up, its light will shine for a sec or two and then the computer should bring up a prompt of some kind. Usually asking you a question - if you have a disk drive, tape drive and how much RAM you have. lol Yeah, you need to tell the computer what it should already know. Just press 'enter' to those queries. The computer is pretty much just a BASIC wedge until you get a DOS disk for it. When the computer works 100%, you insert the DOS disk first and then turn it on. You'll then see the computer booting DOS before it finally asks you for the date.

This gentleman named Ira Goldklang maintains a great site and has been very helpful to me. He's got books, disks, whatever you need (if he happens to have extras at the time) and is usually willing to part with stuff for the cost of shipping plus a 'donation' to his site:

http://www.trs-80.com/

...the arcade type games are absolutely hilarious. Donkey Kong, Berzerk, Scramble, Frogger, Defender - they're so cool for what they are. I also enjoy the text adventures for the system. Great keyboard and classic b/w screen. This was the first computer I ever touched as our Junior High-School had a full lab full of 'em.

Edited by save2600, Mon May 24, 2010 8:36 AM.


#3 Tempest OFFLINE  

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Posted Mon May 24, 2010 8:39 AM

There's a stripped screw on mine, how the heck can I get that out? It's one of the ones that in the recessed holes so it's way down in there.

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#4 save2600 OFFLINE  

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Posted Mon May 24, 2010 8:44 AM

Drill through the stripped screw or if it's in the rear, just see if you can pull the entire thing apart - breaking the mount if you have to. No big whoop if you end up breaking a rear mount :)

Edited by save2600, Mon May 24, 2010 8:45 AM.


#5 Tempest OFFLINE  

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Posted Mon May 24, 2010 8:46 AM

No it's one of the ones on the bottom. I can try and drill it out tonight and see if reseating the chips will work. If anything I can strip out the disk drives.

How does the case come apart. From what I can tell it comes apart in two halves near the bottom.

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#6 save2600 OFFLINE  

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Posted Mon May 24, 2010 8:50 AM

Yeah, there are several philips screws on the bottom of the machine. 3 in the front 2-3 each on the sides and a few in the rear (something like that). Some are machine screws, others have the pointy ends and look like a large wood screw. Once you get all of 'em out, you simply lift the entire case up and over. Be careful as the yoke of the monitor is close by the CPU cage. Don't want to accidentally break that - DOH! There will be a ground wire and power connector going to the CRT as well that needs to be disconnected.

If your CPU board is unhacked - meaning, it's encased in a stainless steel RF shield, don't despair. Just remove the umpteen screws for that, the keyboard cable and drive cable and be sure to bring your patience with too. Best tool you can have in this case ;-) lol

And yeah, those disk drives rock. They're built extremely well and are designed to last. They even have the strobe marking on their flywheel for easy calibration (just need a strobe light). The drives themselves are worth $30-$50ea. at least.

Edited by save2600, Mon May 24, 2010 8:55 AM.


#7 Tempest OFFLINE  

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Posted Mon May 24, 2010 9:00 AM

Yeah it's the two screws on the sides that are the problem. I'll try again tonight.

I hope I can get it working. The machine is in decent shape, the case has some wear and tear like wear spots where the owner rested his wrists and scratches on the top of the case (probably from me trying to open it yesterday), but the rest of it seems to be in good shape. The system powers up, the drive spins, and then nothing happens. If I push reset it will reboot the system. To me this means that the system is working, but the monitor is either shot or broken somehow. I don't know if reseating the chips will help this problem, but I'm willing to give it a shot.

Assuming I do get it all working again. Is there some place I can get paint to touch up the case?

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#8 save2600 OFFLINE  

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Posted Mon May 24, 2010 9:09 AM

People have talked about vinyl die for some of these plastic restore projects, but I've never tried it myself. I like the thought of dying the plastic though vs. painting it.

Those screws in the side. I wonder... if you have bad luck drilling 'em out if you might be able to take that sawblade piece on a Dremmel kit to it. Those things are super thin, but slice through just about anything.

And yeah - if after playing with the brightness and contrast controls you still don't see a ghosted white or horizontal lines that are somewhat angled, might be your monitor is bad. Good news is I doubt it. That was a decent RCA XL-100 monitor and I'm 99% sure it's fused. Yay for fuses! Bad news is, the fuse probably just didn't accidentally die. Might have a power supply issue in the monitor. Could also be a bad connection going to the yoke - but I kinda doubt. And it *could* be the video display chip needs re-seating. Who knows though until you finally get that puppy cracked open.

Edited by save2600, Mon May 24, 2010 9:11 AM.


#9 R.Cade OFFLINE  

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Posted Mon May 24, 2010 9:16 AM

This gentleman named Ira Goldklang maintains a great site and has been very helpful to me. He's got books, disks, whatever you need (if he happens to have extras at the time) and is usually willing to part with stuff for the cost of shipping plus a 'donation' to his site:

http://www.trs-80.com/

...the arcade type games are absolutely hilarious. Donkey Kong, Berzerk, Scramble, Frogger, Defender - they're so cool for what they are. I also enjoy the text adventures for the system. Great keyboard and classic b/w screen. This was the first computer I ever touched as our Junior High-School had a full lab full of 'em.


Some of the games are really amazing for this system even with the limited hardware. There is a game that is like "House of the Dead" (13 Ghosts?) with parallax scrolling and everything. Really amazing what some people did back then!

Edited by R.Cade, Mon May 24, 2010 9:18 AM.


#10 save2600 OFFLINE  

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Posted Mon May 24, 2010 9:21 AM

Some of the games are really amazing for this system even with the limited hardware. There is a game that is like "House of the Dead" with parallax scrolling and everything. Really amazing what some people did back then!

Indeed ...and to clarify what I mean by "hilarious", is how astonished you are after seeing some of these games, how well they look and play. They really are that good. Not much in the way of sounds though :(

R.Cade... have you heard of this mode or device that used the tape output for sounds? Also, one of the Model III's I had... someone had jury rigged a controller to it once. Super simple mod. Guy just soldered wires off the back of the keyboard is all. Cursor keys and space bar for 'fire' I believe is all that's required. Would be easy to make a DB9 port from an old Sega extension cable for one - although there's something kinda cool about using the keyboard for these games, as awkward as it is (cursor keys are on opposite sides of the keyboard) :lol:



#11 Tempest OFFLINE  

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Posted Mon May 24, 2010 9:26 AM

People have talked about vinyl die for some of these plastic restore projects, but I've never tried it myself. I like the thought of dying the plastic though vs. painting it.

Those screws in the side. I wonder... if you have bad luck drilling 'em out if you might be able to take that sawblade piece on a Dremmel kit to it. Those things are super thin, but slice through just about anything.

And yeah - if after playing with the brightness and contrast controls you still don't see a ghosted white or horizontal lines that are somewhat angled, might be your monitor is bad. Good news is I doubt it. That was a decent RCA XL-100 monitor and I'm 99% sure it's fused. Yay for fuses! Bad news is, the fuse probably just didn't accidentally die. Might have a power supply issue in the monitor. Could also be a bad connection going to the yoke - but I kinda doubt. And it *could* be the video display chip needs re-seating. Who knows though until you finally get that puppy cracked open.

The odd thing is that I swear the brightness and contrast control dials barely turned. They're smooth with no grips so it's hard to tell, but I swear they either didn't move or didn't move much. Don't know if this is normal or not though.

I don't see ANYTHING on the monitor. The only thing I see is a flash and a pinpoint of light when I go to turn it off.

Thirteen Ghosts is awesome, I got to play that CCAG. Zaxxon was amazingly decent, I couldn't believe they made a version of it for the TRS-80!

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#12 save2600 OFFLINE  

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Posted Mon May 24, 2010 9:36 AM

Regarding the brightness/contrast wheels - it could be they're stuck up against the case. I've seen that before. And weird they're smooth. Flip the 'puter upside down and see if they're jammed. If so, take a tiny/thin screwdriver to their outermost side and try to slide them closer toward the computer. That should free 'em up. If that still doesn't work - some contact cleaner (not WD-40) may be in order.

The fact the monitor flashes the pinpoint means the fuse isn't bad. Also means the monitor is more than likely good :) Chips and those controls are suspects for sure.

#13 Tempest OFFLINE  

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Posted Mon May 24, 2010 9:39 AM

Regarding the brightness/contrast wheels - it could be they're stuck up against the case. I've seen that before. And weird they're smooth. Flip the 'puter upside down and see if they're jammed. If so, take a tiny/thin screwdriver to their outermost side and try to slide them closer toward the computer. That should free 'em up. If that still doesn't work - some contact cleaner (not WD-40) may be in order.


So they should move a fair bit then? I'll take a look at that tonight.

#14 save2600 OFFLINE  

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Posted Mon May 24, 2010 9:44 AM

So they should move a fair bit then? I'll take a look at that tonight.

Oh yeah, nearly 360˙. Maybe you're problem is as simple as that! lol

#15 Tempest OFFLINE  

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Posted Mon May 24, 2010 10:08 AM

So is there any reason to go with a model 1 (with expansion interface) over a model III or 4?

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#16 save2600 OFFLINE  

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Posted Mon May 24, 2010 10:15 AM

No reason to. You'd just be limiting yourself app wise one would think. I'd stick with a III or IV, unless you have a line on a really nice I setup w/ expanded RAM (you really want 48k if you're going to do the TRS-80 thing), drives and such - all for next to nothing.

Edited by save2600, Mon May 24, 2010 10:16 AM.


#17 Tempest OFFLINE  

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Posted Mon May 24, 2010 10:20 AM

No reason to. You'd just be limiting yourself app wise one would think. I'd stick with a III or IV, unless you have a line on a really nice I setup w/ expanded RAM (you really want 48k if you're going to do the TRS-80 thing), drives and such - all for next to nothing.

Well apps aren't an issue since I'd only be using it for games (unless that's what you meant). I was curious if a pimped out model 1 is comparable to a model III or 4.

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#18 save2600 OFFLINE  

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Posted Mon May 24, 2010 10:36 AM

I don't have all the details memorized, but the differences seem to be in ROM, RAM and drives. Model I drives do not have as much capacity as the ones used in the III. You might only be able to upgrade a Model I to only 16k of RAM. Oh and the Model III has a faster processor than a Model I IIRC.

And yes, by apps - I meant games :) Most of the "modern" ones I've seen seem to require 32k+.

Check out Ira's site to get a much better scoop on these things:

http://www.trs-80.co...r-line/model-i/

http://www.trs-80.co...line/model-iii/

Edited by save2600, Mon May 24, 2010 10:37 AM.


#19 Tempest OFFLINE  

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Posted Mon May 24, 2010 10:42 AM

You might only be able to upgrade a Model I to only 16k of RAM.

Correct, but the expansion interface brings that up to 48K. Still, I'm not sure how compatible that memory is. The TRS-80 is a mystery to me.

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#20 save2600 OFFLINE  

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Posted Mon May 24, 2010 10:49 AM

Unless something's changed with your setup lately, I'd think a Model I would take up more than its fair share of space. At least the Model III+ is all in one case.

Forgot to mention too that there are these disk drive replicator doo-dads. You'll have to do a search (Ira might have them on his site) for 'em, but they're kind of like the uIEC thing for the C= computers. They're not cheap... I thought I saw a price of $200 for one, but it might aid in getting a bunch of software to work on a TRS system if you're after software en masse - once you get your system squared away that is.

BTW: the TRS systems are very cool for what they are - but keep that phrase in context. I have my Model III setup "permanently" in one of my game rooms, but I can count on one hand how many times I've actually played with it since restoring the beastie. Your mileage may vary, but unless you get a real big kick out of playing blocky/primitive/graphically challenged games - you too might end up sitting on a bunch of TRS stuff that's more fun to look at than actually use. :)

Edited by save2600, Mon May 24, 2010 10:52 AM.


#21 Tempest OFFLINE  

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Posted Mon May 24, 2010 6:03 PM

Ok I got the beast open. Now what? The two adjuster dials don't seem to turn more than a millimeter so I might put some lubricant on them and see if that loosens them up. As for the rest of the system, I'm not exactly sure what to look for other than to make sure all the clips and chips are seated properly.

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#22 save2600 OFFLINE  

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Posted Mon May 24, 2010 6:10 PM

Solid state device 101 does not only ensure that chips are seated properly. Oxidation and corrosion form between pins and sockets, so it's not always enough to simply "press down" on chips, listen for the crunch and hope for the best. What you want to do is pull them out, one by one and examine the pins. If they are not too badly discolored, you may pop them back in and press hard. If they are badly discolored then you may either take a fiberglass brush or fine sandpaper to them and re-insert. In extreme cases, sockets may even need to be replaced.

BUT... before you go through all that trouble, get those damn dials to turn nearly 360˙! Be careful what kind of "lubricant" you use. I'd start with contact cleaner. Free those puppies up. Then maybe take a lubricant<>cleaner to 'em. Some cleaners claim they have lubrication built in. Last ditch attempt would include PB lubricant, WD-40 or something to that effect. Just be careful that it doesn't get on any circuitry as it may potentially short them out.

Hell, worst case scenario failing you have anything spray wise... see the three lugs coming off each brightness and contrast pot? You could short those out with a jumper to see if the monitor/computer works... in a pinch. If the pots are sooooo corroded that they cannot be moved... lol

Edited by save2600, Mon May 24, 2010 6:13 PM.


#23 Tempest OFFLINE  

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Posted Mon May 24, 2010 6:32 PM

Ok some limited success. I got the front dial to turn (brightness?) using WD-40 as that's what I had on hand and now I can see diagonal lines on the monitor when I turn the system on. They're really close together at the top and get further apart as they go down. I can get the back dial to turn a little, but it still is very stiff. What does that one control? Are the lines a good or bad sign?

When I open the main case I see what looks like two motherboards in a cage stacked vertically. I'm a bit apprehensive about trying to get them apart unless there's a good reason to do so. For one thing I'm not 100% sure where all the screws to get them apart are.

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#24 save2600 OFFLINE  

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Posted Mon May 24, 2010 6:45 PM

One dial controls picture or brightness (High Voltage off the transformer), the other controls contrast. The two will "dial" in your picture.

There are TWO CPU boards - one is a main CPU board that has the RAM, Z80A, ROM and Video Display Chip. The other is a Disk Controller CPU. It's much smaller and is connected via a ribbon cable that probably needs to be rebuilt. The cables on that were extremely chinsey and glued together. Mirage has probably one of the more reliable disk controller to mainboard connectors possible... I hardwired the two bitches together. lol

BTW: Lines are a good sign. Keep the mirror, razor blade and Led Zepplin album far away though :lol:

Edited by save2600, Mon May 24, 2010 6:46 PM.


#25 Tempest OFFLINE  

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Posted Mon May 24, 2010 6:48 PM

Ok so I should take the boards out and make sure they're all seated properly? What do you think the problem is at this point?




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