johndias

OK thank you! I was looking at a blog on the Model 4 so that's why I was in the wrong port. However, I did change it and the result is that it takes several seconds longer to return the illegal drive error.

Hi all, I wanted to share this because I found it interesting and I've gotten so much help from these forums I'm excited I have info to give back to the community! Anyway, the keyboard on my model III worked fine with the exception of the "," key. So, I searched here, watched some videos and read some blogs and I was fully prepared to address with repair to the graphite pad on the plunger. To my surprise, that is not at all what I found! First, I noticed that the PCB looked a lot less "busy" with fewer solder points... Indeed, after removing the problem switch I understood I was dealing with something different than what I've seen in tutorials. The switch only has two conductors. Here's the switch disassembled : The way that this works is the plunger (on the right) has a shim that pushes against a plastic tab on the contact mechanism (left). This makes the connection between the two contacts which are separated by a plastic insulator. Some closeups of the contact mechanism... maybe hard to see, but on the side view there's a thin plastic layer between the two conductive plates. The metal tab is springy and is pushed down by the plunger shim. Here I've removed the metal spring to expose the plastic tab that forces contact between the two conductors. Testing the contact mechanism by pushing down on the plastic tab with a screwdriver tip. In the end, I found nothing at all wrong with the switch. It wasn't even dirty, although I suspect that maybe some debris got lodged in the mechanism and when I disassembled it the debris was knocked loose. Anyway, I soldered it back in place and my "," key works fine now! Hope this helps someone who ends up with a keyboard similar to mine! In the end, this looks like a much better design than the graphite and rubber boot switches I've seen others have to deal with - hopefully less prone to problems.

OK, gave that a shot but still get Illegal drive number ... here also are my cables and jumper settings.

My TRS-80 Model III has two working floppies, but I wanted to add the Gotek mod as an external drive(s). Everything looks OK, and I've tried multiple cables from the disk connection on the bottom to the Gotek (one factory made the other I made). I only have two physical floppies, LDOS 5.1.3 and Super Utility. Even though I have a disk mounted in the Gotek, the computer doesn't recognize that the drive even exists. Any ideas on what could be wrong with my setup?

Thanks @jamm agree it would be great to have access to the source code. Are there any other loader alternatives?

So, even with the fixed version on Lotharek's website I find that there are some functions that don't work ("?" for search, numbers to load disks) and if I browse into a directory with a lot of files (maybe more than 30?) the whole thing locks up. Any idea where you found your fixed version @StickJock?

Hmm, maybe I'll attempt that downgrade. Actually, I see he's got a "fixed" loader for 400/800 on the files section of the product page. Hmmmmmm..... ....annnnnnd that fixed it!

Ah, it's stock RAM so that must be the problem. What are my options to upgrade the memory? Sorry, it's been a while since I pulled this guy out. It does have the 48k upgrade.

I bought the Lotharek Biggus Dickus SIO2SD. Seems to work fine if I use the LCD screen to load software, but when I try to use the loader it comes up but I can't get the keyboard or joystick to respond and navigate the menu. Am I doing something wrong?

So I finally ordered another 410 to cannibalize and since it had a working STOP button, I pulled the "keeper" bar from it installed it in my original. And it worked! I see no visual difference between the two but that seems to have been the problem - some slight wearing of the plastic I guess. This is the bad part.

Hmm, wonder if I can put a bit of heat shrink tubing over it. I may try that, although I wonder if it will cause problems with de-latching.

No worries, thanks for the help! I did break it down and clean everything - no dice. At this point I really feel like the plastic post that is supposed to be held in by the white retainer slider thingy is just slightly worn enough to not fully catch. I'm writing this off and searching for another one on eBay - maybe between two of them I can get a working program recorder!

I have tested powered and connected to my 400. It doesn't stay down, but if I hold it down the tape will actually play when using CLOAD.

It's not staying in at all, no power and no tape. Very occasionally I can get it to stick but it is very tenuous even then. Thanks for that deep dive, I'll pull it apart this evening and see if I can clean it up. As I recall, that mechanism was a bit stiff. I was trying to avoid tearing it all down as I was afraid I'd make things worse, but I think this is going to be necessary.

Thanks, that's helpful - so I looked into that part and it seems to be OK, but of course having no reference with a working one I'm not sure. Here are two pics, one with the play button "up" and the other with me holding it "down" - the mechanism looks to be moving freely (and I was able to move it with a metal pick tool).

No dice. I think the spring's got plenty of tension though. I'm starting to think that there is wear on the plastics that allowing it to slip. I haven't pulled the sliders out, but I did get in there with a pick and tried to remove any dirt and fibers, it moves freely. Maybe I should get another one for parts and try replacing that lower slider.

I'll give that a shot! Thanks.

Thanks, I took another look after reading your reply. There's a white bar that is pushed by a spring to lock the FF,RW and PLAY into place. It looks to me like there's just a little loss of tension on that spring causing it to not fully lock the play. Now, to find that spring for sale!

I've been working on this 410, cleaning, replace belts, etc. REW, FF work but I cannot for the life of me get the PLAY to stay down when I press it. I can't even see how the key mechanism would latch, like I can see on the other keys. Any pointers are appreciated.

Please add me to the "want" list?

Please add me to the "want" list?

Thanks again - that makes sense. Seems like my timing for working on this project sucks due to the delays the F18 MK2 is having but I'll for sure be interested when/if they can overcome the legal issues.

Hah! Thanks everyone that did the trick! The screen still looks a bit wonky, though. For some reason my phone camera makes it look better than it appears but the letters are not very crisp. I may try another screen, this is an old junker I keep to test stuff with.

Bought a unit off eBay and had to make my own composite cable. When I hooked it up the graphics are kind of nasty and do not fit on the screen. Is this bad video memory or something else?

Well, I'm sure I learned a lot about the POKEY and SIO - that's the silver lining. Bad news is I wasted a lot of my (and the good folks who tried to help) time - my pinouts for TX/RX were reversed. I'm not ashamed to admit when I make a mistake. Thanks again to all the great folks who tried to help. I've got it working now! On to the next challenge!