Outbound Laptop repair/reverse engineering

[zigzagjoe]

Lacking a more obvious repository, seems like it's time to start a outbound laptop worklog thread.

I've managed to capture an image of the prairietek 240A HD that came with my machine. While it's not remotely a clean image (contains a broken mix of sys 7 and 6.0.8), it's useful as a starting point as something that is known to boot on a physical machine. It's pretty obviously byteswapped and appears to be treated as a giant floppy (ie. no partition table), not particularly surprising on either count. I've attached both the original image and a byteswapped version - would be interesting to try to undelete files from it.

I was able to capture the image by attaching the HD to an old via industrial PC with an IDE interface and a DIY power adapter. I didn't have any luck getting a USB adapter to talk to the drive, but the via machine worked right off the bat. The IDE connector appears to use the standard pinout. Pinout of the power connector is simple: pin 1 is 5V, pin 2 is GND, pin 3 is 12V. Attached is a terrible diagram.

I intend to try to poke at getting a zuluide or old CF card working once I have my machine fully refurbished. I'm expecting I'll probably need to decompile the .PTek driver in the eeprom, I'm sure it's primitive and I'll need to know what it's expecting and/or perhaps modify it.

Appears to be the correct replacement battery, but I've not yet received it: EPP-100C, aka panasonic BP-80 and a bunch of other x-refs.

I've dumped contents of the internal eeproms (2x xicor 28C64). My machine had HDD version 1.1e written but I've included 1.3b2 images which I extracted from the attached installer disk (not my image).

I'm working on refurbishing my external floppy drive. It was riddled with a few nasty SMD caps. Otherwise, it's a rather strange beastie that contains an off the shelf WDC floppy controller, a SCC (???), and more ROM on the PCB. The floppy is a Citizen mechanism which uses a 230mm x 2mm belt. The additional ROM (contents attached) only seems to be used if the HD eeprom image is written to the internal EEPROM. I'm guessing the internal floppy EEPROM assumes the internal drive would be used for booting.

Also attached is a capacitor list with mouser replacements for both the logic board, internal power supply, and external floppy. A couple of the logic board caps (220uf 10v) should really be replaced with short 6mm or so capacitors; on my machine these two were bodged in sideways in order to reduce the height. Note the bipolar cap in the floppy drive! I missed this, so for the moment I've left it alone as it was the only SMD cap in there that appears in good condition.

 

[eharmon]

I've attached both the original image and a byteswapped version - would be interesting to try to undelete files from it.

Norton UnErase didn't find anything interesting on the disk image.

 

[cheesestraws]

Woo! Excellent to have an image finally. Giant floppy is perhaps the outcome one should have expected, buit!

 

[3lectr1cPPC]

I'll go ahead and add the cap reference to MacDat: https://macdat.net/repair/cap_reference.html

Can't wait to see what you accomplish with this project!

Edit: The cap reference ZIP file seems to be corrupted - showing as 1K and Windows says it's empty.

 

[Trash80toHP_Mini]

@trag how about hopping onto this bandwagon? Your in depth Outbound chops would be greatly appreciated I'm sure.

 

[zigzagjoe]

Norton UnErase didn't find anything interesting on the disk image.

Ah well. Thanks for trying. It looks to me like someone played with the laptop after its original service life ended, tried to upgrade it to 7.0 and deleted all the applications and ended up with a broken mix of the two. I was curious if there was anything that could be pulled back, but the information on the format was the most important part anyways.

I'll go ahead and add the cap reference to MacDat: https://macdat.net/repair/cap_reference.html

Can't wait to see what you accomplish with this project!

Edit: The cap reference ZIP file seems to be corrupted - showing as 1K and Windows says it's empty.

Ugh, 7zip made me a blank zip as I'd had the file open. A good copy is attached. The power board is rather cramped and some of these are bodged in, so references aren't always present.

--

I've gotten a replacement floppy belt printed in TPU. 225mm and 0.8mm thickness seems to be close enough to work. To get a good section of the belt I printed it with extra height then used a scalpel to begin a split along a layer line to the correct height as I was having some trouble with the initial layers thickness/quality.

My machine has an odd behavior where it doesn't boot sometimes/display refresh issues that are sometimes resolved by touching/flexing the LB... still have to troubleshoot that.

 

[jake18125]

Hah that's funny, I was just thinking about the outbounds floppy controller today when I stumbled across this thread!

So at least it's good to know that it really is an SCC with an off the shelf floppy controller running the show.

I wonder if the signals to the citizen floppy drive from the adapter board are similar enough or identical to an actual superdrive.

 

[zigzagjoe]

Hah that's funny, I was just thinking about the outbounds floppy controller today when I stumbled across this thread!

So at least it's good to know that it really is an SCC with an off the shelf floppy controller running the show.

I wonder if the signals to the citizen floppy drive from the adapter board are similar enough or identical to an actual superdrive.

Rather the opposite - seemingly a standard PC type drive that they're doing shenanigans to make mac formats work. Supposedly it allows 1.4mb Mac formatted floppies, in addition to 800k and 400k. Functionally similar but entirely different.

I believe there was a thread where someone said they managed to get a floppy emulator to work in place of the original drive.

 

[SuperSVGA]

The Gotek/Flashfloppy emulators work fine at least for 1.4MB disks, I have one running on mine since my physical floppy drive doesn't seem to work.

 

[zigzagjoe]

Here's a clean(er) 6.0.8 image. I prepared this in an emulator, copied over the outbound bits from my drive, then byteswapped it and wrote it to the original HDD. It still complains about AppleTalk; I haven't tested it if works yet as this system 6 install was originally used on a SE/30. At least this isn't some awful mix of 7 and 6.0.8 and includes a variety of utilities on disk. The installed outbound drivers are for the 1.1 eeprom but I've included the 1.3 installer disk (attached in prior post) as a folder on disk. You can drag the contents to the ramdisk, boot off it, and install it.

I've grabbed the HD parameters too. As expected it seems to be a CHS-only drive without LBA, I expect the driver is making assumptions about the disk geometry so that'd explain why newer drives/CF cards were problematic. I've got a zuluide on the way to test that theory. Important part is 615 cylinders, 4 heads, 34 sectors/track.

Also attached is the HD firmware. The physical chip was labeled CODE: 005 REV G and is a 27*256 type. Maybe this could help revive some dead drives. Note: it's expected behavior that the drive won't automatically spin up until it receives a command requiring it to, and I found with a couple USB adapters they'd never cause it to do so.

The Gotek/Flashfloppy emulators work fine at least for 1.4MB disks, I have one running on mine since my physical floppy drive doesn't seem to work.

Did you have to do any adaptation? I kind of doubt it's going to work with macintosh disk images (at least, smaller than 1.4) but could be a good other option to have. Or, I might just find another floppy mechanism that isn't quite as cursed as this citizen drive seems to be.

I've recapped my floppy drive and printed it a new belt, it at least tries to do something but seems to try to seek past the limit so I'm not sure it's all there. I will have to try to track down a 2.2uf bipolar cap (or a MLCC) and see if that makes it behave better.

 

[eharmon]

I've grabbed the HD parameters too. As expected it seems to be a CHS-only drive without LBA, I expect the driver is making assumptions about the disk geometry so that'd explain why newer drives/CF cards were problematic. I've got a zuluide on the way to test that theory. Important part is 615 cylinders, 4 heads, 34 sectors/track.

With the right factory software, some CF cards can have their CHS values re-programmed, if you want an emulator-less experience.

Unfortunately I've never had the right combo of card and software to try it myself, so I can't recommend a specific model.

 

[zigzagjoe]

With the right factory software, some CF cards can have their CHS values re-programmed, if you want an emulator-less experience.

Unfortunately I've never had the right combo of card and software to try it myself, so I can't recommend a specific model.

I'd like that better in the long run, possibly, but at this point I'll call it a win if I can get it talking to anything but the original HD. That way if/when it dies there's another option out there for those in need.

Another thought I had was as long as the target card/drive has the same or greater values for C H and S, I was thinking perhaps you could write a manipulated image to a drive and achieve a similar result. Or, write the image using software capable of CHS addressing - probably some DOS utilities could do this.

 

[SuperSVGA]

Did you have to do any adaptation?

No modifications other than converting to the right connector.

I kind of doubt it's going to work with macintosh disk images (at least, smaller than 1.4)

I unfortunately have no idea whether it can work with emulated 800k disks, for some reason the mouse doesn't work on mine so I can't do much interaction with it to even try. It seems like it could be made to work since Flashfloppy supports some odder formats, but it depends on what the controller is doing to make it work in the first place. I haven't got that far in the code yet.