LisaList2

The SG3524 pulse width modulator is used on the daughterboard in the "DataPower" variant of the Lisa Power Supply, often referred to as the "1.8A" PSU due to the rating label.

This component does sometimes fail, but is not often a problem.

This part is responsible for regulating the +5V used for the PSU's internal logic (it does not exit the PSU), as well as being the comparison reference used for adjusting the PSU output and detecting over-voltage and over-current conditions.

The datasheet formula for the oscillation frequency predicts 51.5 KHz with the components used.

Quote from: berskyboy on September 21, 2026, 09:36:41 AMHere's a few more measurements

From those, I don't see any obvious issues on the main board with Q1 and Q2 removed from the circuit.

(For future reference, I'm assuming the lower Q4, Q3 c-b measurement is due to a difference in DMM characteristics, and that Q4, Q3 e-b is with the daughterboard installed.)

Temporarily overloading the output is a condition that the PSU design anticipates and normally protects from and survives without damage.

So the likely cause of the failure of Q1 and Q2 is the solder bridge(s). Since a solder bridge is an unusual cause of failure, we can't be confident that Q1 and Q2 are the only components that need to be replaced.

I'll work on some measurement instructions to look for further failures on the daughterboard. In the meantime:

Use the image below to diligently check for any remaining solder bridges. If any remain, then Q1 and Q2 may be destroyed again after replacement, and further parts may be damaged too. Shiny solder joints hide subtle details, so after fully checking it once, it can be helpful to rotate the board and check again from a different angle.

If you find any bridges, take a picture/make a note of where they are as that information can help locate and/or eliminate additional components to suspect.

LOS Games floppy -- three new games for the Lisa Office System on one disk

A single 400K floppy image with the native LOS games that have appeared
this year, gathered with their authors' permission so they can be
installed in one go:

TETRIS          by ried -- the falling-tile classic, real time on the
                  Lisa desktop.

Minesweeper     by Alex Anderson-McLeod -- the minefield puzzle, with
                  the LisaFPGA author's blessing to distribute freely
                  (source on his GitHub).

Lisa Slide Puzzle  by T. O'Connor -- sliding tiles cut from the LISA
                  Slide Show's pictures; [one sample picture and
                  LisaFileMover 1.1 are on the disk for adding more].

Where to get it

The Apple Lisa BBS:  telnet theapplelisabbs.duckdns.org 1983
                         Floppy Images > Releases:  [LOS_GAMES_1_0.dc42]

GlobalTalk:          LisaGaming Zone

LISAList2 (here)

68kMLA

Installing

    Mount the image, open the floppy, and drag or duplicate each game
    onto your hard disk.  All three run under LOS 3.1; tested on a Lisa
    2/10.  Each author keeps their own source: TETRIS [ried's repo],
    Minesweeper [Alex's repo], Slide Puzzle at
    github.com/GyroPilot/Apple-LisaSlidePuzzle.

Note: Use Lisa File Move to move .pix files from the floppy to HD.

  Thanks to ried and Alex for saying yes.

  T. O'Connor (bmwcyclist), September 2026

Lisa Slide Puzzle 1.0 -- a sliding-tile game for the Office System

A new native LOS tool: each 680 x 300 picture from the LISA Slide Show
becomes twelve tiles with one missing, scrambled by 150 random legal
moves. 

Slide them back with the keypad (8 2 4 6 move the gap) or by
clicking a tile in the gap's row or column, which slides the whole run.
S peeks at the finished picture, N scrambles again, the Puzzle menu
moves to the next or previous picture or gives up, and the gap keeps
the move count.  "Solved in N moves!" when the last tile drops in.

Pictures
   
It plays whatever .PIX files are on the disk it lives on -- the same
files as the slide show and its picture packs.  The floppy carries
one sample picture and LisaFileMover 1.1, so copying more pictures
on is a Copy in the file mover (E .PIX, A, Apple-B for a whole pack).

Where to get it

The Apple Lisa BBS:  telnet theapplelisabbs.duckdns.org 1983
Floppy Images > Releases:  LISA_PUZZLE_1_0.dc42

GlobalTalk:          LisaGaming Zone

LisaList2 (here)

68KMLA

Source code:         github.com/GyroPilot/Apple-LisaSlidePuzzle

Installing

Mount the image, open the floppy, drag or duplicate Lisa Slide Puzzle
onto your hard disk (and LisaFileMover, if you do not have it).
   

Tested on a Lisa 2/10 under LOS 3.1.  Tool 419308.

T. O'Connor (bmwcyclist), September 2026

Quote from: stepleton on September 20, 2026, 06:06:02 PMWould there be any chance of organising this code into a few separate modules?

The code is split into two python files: the "add file" related code is in the 2nd file, and uses (imports) routines from the 1st file). If you have something else in mind, send me a pull request, I will accept your changes.

Quote from: stepleton on September 20, 2026, 06:06:02 PMFinally, now that you've got a way to write to files: can you write a script that deposits a compilable set of Lisa Office System source code files onto a hard drive image? Would be a real stress test!

Yes, this has been my end goal. The script is ready at https://github.com/TorZidan/LisaFileSystemTool/blob/main/LisaSourceCompilation/upload_files.sh . It works great and adds successfully 858 lisa source files.
The files look great in Workshop File Manager and the Workshop Editor. However, compiling them fails "midway" (after hundreds of files are being compiled), and LisaEm crashes and exits into the "debugger". I will figure it out eventually. It could be a LisaEm bug...

Reserving more numbers in my block, please:

419312  Galaxy Patrol  - a graphical LOS version of the 1971 public-domain
        "Star Trek" game (own name, own ship names). Queued after Reversi.
419313  Moon lander    - slow-real-time lander, public-domain 1969/1973 originals.
419314  Checkers       - draughts vs the Lisa.

Status of the earlier ones: 419311 LisaFileMover is released (1.1),
419308 Lisa Slide Puzzle is in test, 419309 Reversi is next, 419310 (the
installer) is parked. (not able to achieve what I wanted)

Still waiting to find out if anyone is working on an improved icon editor...

Quote from: sigma7 on September 19, 2026, 04:27:33 PMCheck this again, if it is a short circuit, it should be bidirectional.

With Q1 and Q2 and CR18 still out of circuit, do these again using the diode test (we are looking for additional problems):

Morning,

Here's a few more measurements:

{AA, AB}   0.46, inf   CR18, CR19   AA:0.469, OL AB: 0.476, OL
{BA, BB}   0.13, inf   CR18, CR19   BA: 0.132, climbing BB: 0.132,climbinng
{CA, CB, CC, CD}   0.5, inf   CR1, CR2, CR3, CR4   CA: 0.473,OL CB:0.480, OL CC:0.476, OL DC:0.468, OL
{DA, DB}   0.30, 0.37   CR25, CR23   DA: 0.26, 0.277 DB: 0.263, 0.275
{EA, EB}   0.38, inf   CR26, CR24   EA: 0.392 , climbing, EB: 0.392, OL
{FA, FB}   0.41, inf   CR22, CR21   FA: 0.392, OL FB: 0.391, OL
.         
Transistors         
Red-Blk      Description   
{1-2, 4-5}   1.25   Q4, Q3 c-b   0.775, 0.767
{2-1, 5-4}   0.62   Q4, Q3 b-c   0.572, 0.566
{1-3, 4-6}   0.70   Q4, Q3 c-e   0.661, 0.681
{3-1, 6-4}   1.89   Q4, Q3 e-c   1.583, 1.585
{2-3. 5-6}   0.64   Q4, Q3 b-e   0.612, 0.618
{3-2, 6-5}   inf   Q4, Q3 e-b   1.712, 1.725 // 0.731 , OL
         
{7-8, 10-11}   0.00   Q2, Q1 e-b (in parallel with pulse transformer)   Ov, 0v
{8-7, 11-10}   0.00   Q2, Q1 b-e (in parallel with pulse transformer)   0v, 0v

great project!

Let me know if there is anything you want me to try!

That is impressive.

Would there be any chance of organising this code into a few separate modules? All in one file is convenient, but it looks like there are some handy routines here that would be nice to use from other programs. You could have a module for disk image I/O, a module for filesystem metadata, routines for traversing the FS, routines for retrieving and creating files, etc.

Either way, one thing that seems like it could be fun would be some visualisation of the sector bitmap. I'm imagining something that resembles the diagram of occupied sectors in a disk defrag tool...

Finally, now that you've got a way to write to files: can you write a script that deposits a compilable set of Lisa Office System source code files onto a hard drive image? Would be a real stress test!

Cheers,
--T

Thanks for testing that! I'll admit I haven't put too much time into the gameplay, yet, and that switch to black is a little concerning. I'll have to dig into it. Regardless, I'm glad to see it working on real hardware and that you have the RAM to push it.

This started out as a "port" of Doom8088 within Uniplus, and it works there but is tight on RAM. I think pushed it to load directly from ROM which helps on the RAM and performance side. The bitmap is good, but the shading is definitely an issue, as you can see!

I'll push everything to a repo that includes the Unix and standalone builds. The cool think is that this was built with gcc on macOS 26 and dropped onto the disk in both cases. There are some handy scripts that came out of this to inject files into the Unix disk image and a regular 'profile' image that I'm sure can come in handy. We all probably have 30 variations of the same thing.