LisaList2

I have a Lisa with working Twiggy drives, and might be available to help with archiving Twiggy media.

General location: Boston, MA USA
Number of working drives: 2
Experience archiving Twiggy Media: Lots, very experienced
Have archiving setup at hand (BLU & serial connection to modern computer for file transfers): Yes

If the timing logic looks to be working properly, then we're headed back to square 1 to investigate what is currently happening.

Suggestions:

After you press reset, does /BERR do any cycling?

If /BERR cycles:

• does it continue cycling perpetually, or stop until reset again?
• (and) disable the bus timeout and probe the 68k address lines to find out what address is causing the first bus error after reset.
  

If /BERR doesn't cycle, does /AS cycle perpetually?

If /AS cycles:

• check that the EPROM output enables are cycling (U13D-22 and U14D-22)
• check /DTACK is cycling
  

If /AS does not cycle, check /RESET, /HALT, /BR, /BERR at the 68k.

edit for future cases: also check CLK at the 68K is about 5 MHz, as without a running clock, nothing is likely to work.

Many thanks, everyone! I'm glad my hunch was correct, but, wow! who would have put the PSU in this configuration?? Kind regards.

I wonder what the extra jumper wire on the E6 line is for (in OP's picture). It would seem to be a jumper connecting to... itself? On the same trace?

It is in a parking position. It used to be connected to E7 for 115V operation and now, after conversion to 230V, it is dangling. The left jumper was connected to E8 for 115V and has now been moved to E7. This puts both transformer windings in series for 230V operation. Before, for 115V, they were in parallel.

Thanks for this detailed writeup! I took another look at things, and here's what I discovered.
First of all, for whatever reason, the screen seems to have changed somewhat since the last time I powered on this Lisa. Now the raster lines don't blink, and what I get is a rhythmic cascading of dots down the screen. I can share another video if that helps.

The counters U1C, U6F, and U5E are both counting and output as expected.

U4A-4 and U4A-5 are both active.

U1D seems to be working; all outputs are active at ~2.5MHz (half a clock cycle) as you described.

I checked the flip-flops at U3C, U2B, U3B, and U4B. None of the Q - /Q outputs seem to be stuck, and they work as I expect.

I wonder what the extra jumper wire on the E6 line is for (in OP's picture). It would seem to be a jumper connecting to... itself? On the same trace?

http://appleclub.pl/wp-content/uploads/2018/04/DSCF3440.jpg


Only one , near AC in

Another for the spreadsheet.

Model: A6S0300
Memory Option: A6S0304
Serial number: A3356182
Applenet number: 00102186
Manufactured: 3356

Here is a photo of the 230 V configuration: https://upload.wikimedia.org/wikipedia/commons/1/11/Apple_Lisa_Teardown_%2816065582186%29.jpg

Both windings of the standby transformer must be in series, not parallel,  and the input of the main regulator must be configured as a bridge rectifier and not as a voltage doubler. So yes, the lower jumper is the culprit.

Could anyone please confirm for me the jumper settings for 230V for a DataPower 15A0202-000,001 power supply? I bought the Lisa in this configuration in the UK, but it had suffered a blown fuse, a vaporised trace underneath the PSU board and cracked RIFAs.

Attached is a top-down view of the power supply board with callouts for the jumpers, set in the state in which it arrived. (Please ignore that I have pulled the RIFAs and one of the tank capacitors, which was bulging on the top). Of the two jumpers at the top, only one is bridging the 230V terminals; the other jumper in this area is not connected at one end. The jumper at the bottom is bridging the "115V" terminals (YIKEES!). I cannot see any reason for this jumper to be connected for a 230V input supply. The vaporised trace and blown RIFAs are in this area of the board.

As soon as my replacement RIFAs arrive, I'll test the board with the lower 115V jumper disconnected and see what happens (although, if this is the culprit it's likely affected other components on the board). I'm just asking for confirmation of my hunch that this jumper is the culprit..

Best regards, Kevin (Insanely Digital)