Recent content by NRoach44

Oooh, very nice! Would you be open to taking pictures of the board?

Heya! There's been no further development as I've got other projects I've been working and spending money on, and the difficulty sourcing the exact right parts. The kicad files I used to generate the gerbers for the board that cj7hawk and I have assembled are here...

I have fixed mine by pointing the hot air gun on my SMD rework station at the back of the keyboard (the metal support) for ~30s at ~300 degC until the short cleared. The first time I did it needed more time. This does require using a multimeter to find out which two keys are shorted, so you can...

Looking at the service manual, testing the Screen-Pac post-install is: Insert the Extended Utility Diskette in A Insert WordStar into B Per the Screen-Pac User's guide, Sysgen the screen-pac CP/M from the Utility Diskette onto B Set up WordStar for 80-column (per pages 7-10 of Screenpac User's...

Okay I suspect D2 is *part* of my problem. 8.7 or 9.1 on VDA (even making sure it's not being regulated down) doesn't change anything, so it's not the op-amp limiting due to it's supply. With U5 & U7 removed, I get the same voltages at R5/2, and R7/D2 as with them added back in. If D2 is meant...

No, I haven't gotten the Gotek into write mode yet, but that may be because I've been running the upgrade card in "passthrough mode" (without the card's RDCLK and RDDATA, but DDEN pulled low). I think I tried much earlier today to no avail. that behaviour being some kind of controller...

Yeah, C17 is the electrolytic on the side, so I'm not too phased about that. After studying the schematics, and playing around a bit, I see the "snapping on" behaviour you mentioned. U7 and downstream of that is responsible for finding a bias to nudge the 1MHz signal from U8,9,10 up and down...

I checked through my build once more, this time checking every component against the official schematics, and realised I'd put a 47nF cap in C3, instead of 47pF. I swapped it out, and no dice. I can get U9 up to 981 MHz, but no further. I'll check voltages again later, but I may end up just...

Perfect! I imagine write should be much easier to get working as the circuit is much simpler than the read section. While the iron is hot, what did you substitute, and was it from the Sam's, official or my schematics? I may just end up updating the schematics to suit, or at least note them in...

The underside of that one looks the same as mine. How hard was it to get open? Mine appears to be pretty well glued into it's black case.

That little adaptor came with my otherwise virgin OCC1, so it was on my list to "reproduce" as well. The first edition of "The Portable Companion" (June/July 1982) does mention a simple method of turning it into a composite signal: I've so far not found the article in the other issues, but...

Okay, two main suspects: I think the low analogue voltage is the cause for my frequency woes, so that'll be the first thing I fix / workaround (lab power supply here I come) Since the two flip flops in U5 (74LS107AN) appear to super-impose one another, I'm going to assume that the output of one...

At the moment I've booted the system with the board plugged in only on the 34-pin main cable, the additional 10 / 8 pin that goes across the board isn't connected. I've pulled DDEN to GND and that seems to do the trick. The system will boot normal SD disks like this, so I've booted the...

I've cross checked the Sam's schematics against mine, and found one mistake on mine, and one on theirs (compared to the official OCC schematics). Mine was of no functional consequence: RN5's LATE and CLK was swapped (mine) No pull up on EARLY (Sam's) I also checked the board view to make sure...

Okay, quick status update: Boring life events have slowed down! I've fixed the keyboard (as above) and figured out why - the original cable, right at the fold, presses on the 6&7 or 7&8 keys when the unit is packed up. It'd work all fine and dandy until I packed it up and moved it. Swapped the...