LisaList2

Quote from: sigma7 on Today at 03:25:19 PMWhile you're waiting for those to arrive, anticipate if you will need to procure some additional items to install them.

If you can remove the mica insulators from the old transistors without breaking them, you can re-use them.

I think I can use them and wipe them off

Quote from: sigma7 on Today at 03:25:19 PMIn addition, thermally conductive grease/compound is needed with mica insulators.

I have ordered this.

https://canada.newark.com/wakefield-thermal/120-sa/thermal-grease-compound-packet/dp/00Z1244?CMP=e-email-sys-shipping-GLB-Product

Quote from: TorZidan on September 19, 2026, 04:32:54 PMeverything is complete and well documented

UPDATE:  the "add file to a disk image" feature is fully implemented and works on all versions of the file

Wow, this is really tremendous development - well done!

Quote... AI model running locally on my video card.

Was your use of AI entirely self-hosted, or did you need to use some big/cloud AI too?

If self-hosted AI is sufficient for LOS development, I'd like to do something similar. Do you have advice on what hardware & software I should collect to set it up?

Quote from: berskyboy on Yesterday at 09:38:40 PMfound and bought

While you're waiting for those to arrive, anticipate if you will need to procure some additional items to install them.

If you can remove the mica insulators from the old transistors without breaking them, you can re-use them.

In addition, thermally conductive grease/compound is needed with mica insulators. In a pinch, if the old parts have plenty and it is clean, you can re-use the grease, but cleaning it off and using new grease can help avoid issues. The fancy heatsink compound used for computer CPUs/GPUs is the same type of material (but more expensive) and may be easier to get locally, or you may already have some.

Watch some videos to see how much grease to use... the final layers should be very thin (eg. almost translucent), too much will make thermal transfer worse. You may need slightly more for broad contact if the heatsink surface isn't very flat. Keep grease away from where the leads enter the transistor case.

There is also the option of replacing the grease and mica with a TO-3 shape silicone insulator pad. I've not read confirmations that this works ok in this PSU, but I expect so. The silicone pad option does not need grease; clean off all the old grease if switching to a silicone pad.

If any of the TO-3 mounting screws were difficult to remove, the solder joint between the threaded mounting post and the circuit board may have broken. This is best resoldered without the screw and transistor in place. On the bottom of the main board, carefully check for cracks in the solder around the outside of the threaded mounting posts and resolder if the joint is suspect. Avoid putting more solder in the hole (and remove solder in the hole if possible).

Important: When re-installing the TO-3 transistors, you must complete the physical mounting before soldering the leads. ie. clean and grease the mating surfaces, assemble, and fully tighten the phillips head screws before soldering anything. Soldering too soon introduces mechanical stresses that can damage the transistor and circuit board.

The DataPower PSU was originally wave soldered after the TO-3 transistors were installed. As a result, the transistor mounting screw holes have solder in them. Check carefully that the transistors are rigidly clamped down against the heatsink; if not, the solder in the screw holes may be preventing full engagement of the screws. If you have appropriate equipment, you may be able to remove the solder from the screw holes, or you can use a 6-32 tap or something similar to clear solder from inside the threaded hole. You do not need to re-solder the mounting screws once re-installed.

Once the screws are tightened, check that the insulator has not been compromised by measuring the resistance between the heatsink and the case of the transistor. It should have a very high resistance. The black coating on the heatsink is non-conductive, so you'll need to pierce it, scrape a bit off, or find a spot that isn't black. Measure the resistance from one spot to another on the heatsink to confirm you've established good contact.

Double check that all other components (such as CR18) have been re-installed to return the PSU to the fully assembled state.

https://www.bitsavers.org/pdf/apple/lisa/marketing/Lisa_Sales_Marketing_Binder_Feb84.pdf

Around page 35, or so, Apple mentions "modified their approach to networks". Competing standards had emerged (Ethernet vs TokenRing) and Apple mentions being "neutral" with their AppleBus (AppleTalk) as an interconnect and using gateways to connect to wider networks using whatever standard(s) emerged as the winner(s).

Maybe by the time that sales binder came out they realized leveraging "built-in hardware" across the entire product line was "good enough" to meet customer requirements at the time?

yes, I have Applenet. I reverse-engineered the adaptor board some years ago, and the schematic wound up on bitsavers:

https://www.bitsavers.org/pdf/apple/lisa/appleNet/Applenet_Schematic.pdf

You can find the KiCad schematic files and additional project notes here:

https://codeberg.org/stepleton/applenet

I got partway through reverse-engineering the card's boot ROM but didn't quite finish the job. Somewhere in the LisaList archives you can also find Ray spotting one of the items that puzzled me as a particular kind of CRC calculation. Regardless, it was getting to the point where you would also have to know what the built-in Z8 microcontroller did and also how to understand what the PAL was doing if you wanted to make more progress.

The card's boot ROM does some weird things, like overwriting the location in the Lisa's RAM where the main Lisa boot ROM puts a pointer to the video memory. That's a useful pointer! (The Selector uses it, among other apps.) It's not clear why it does that. My guess is that the AppleNet card is from earlier in the Lisa's development life when the boot ROM organised things differently.

@ried is correct that AppleNet is 100% a dead end. It may have some operational things in common with Ethernet --- it uses CSMA/CD, for example --- but it also seems to do what it does all in its own way. I'm aware of nothing else compatible ever being made, nor of any sign that this was ever a goal. I guess this is the same spirit that brought us Twiggy and Widget.

These days we have advanced tools that can do reverse-engineering very well, much better than I could (or can today)! Revisiting the code with those tools could be interesting --- but from a practical perspective there is is probably not much more that's important to know, in my opinion. (What remains are quite low-level implementation details, in other words.) You could point Claude at the code, schematics, and PAL equations and dump all the remaining low-level details here if you wanted to.

I guess what I'm saying is, though: would that be spoilers?

Quote from: ried on Today at 11:05:20 AMstepleton has one. As far as I know, they are completely distinct from Ethernet and the software enabling it was never completed. It's a technological dead end, and these are really just historical artifacts at this point. I want one because I love the mystery of experimental, unfinished products like that.

understood. It would be great to get LOS on AppleTalk someday!!

stepleton has one. As far as I know, they are completely distinct from Ethernet and the software enabling it was never completed. It's a technological dead end, and these are really just historical artifacts at this point. I want one because I love the mystery of experimental, unfinished products like that.

WTB Untested/Non-working LISA 1.8a Power Supplies.

I would like to become acquainted with restoring/reparing LISA 1.8a PSUs.

If you have an untested or non-working LISA power supply that you are willing to sell please let me know.

Thanks!

That would be great if we can understand how it works and perhaps replicate it!

Quote from: berskyboy on Yesterday at 09:38:40 PMfound and bought from this site the 2N6308

Good choice!

It looks like there are very few TO-3 transistor packages still being made. The plastic case alternative will not be trivial to retrofit in the DataPower PSU.