General Category > LisaList2
Does anyone have a spare Lisa motherboard?
Lisa2:
If you get your serial ports working you can use BLU to dump the roms.
http://sigmasevensystems.com/BLU.html
rayarachelian:
--- Quote from: AlexTheCat123 on November 22, 2019, 01:40:31 pm ---Wow! I didn't even know about this! Thanks for the info!
--- End quote ---
You're welcome. Tom does log on here occasionally so you can ping him about it. He's awesome. He had one of the earliest websites about the Lisa on the internet. You can find it here off archive.org, though some images might be missing here and there. https://web.archive.org/web/20021225192819/http://tangerinecs.com/~amber/lisa/saq.html :)
--- Quote ---The entire screen is definitely visible and I have tried pressing the reset button so that I can see the entire boot sequence, but it never displays the version. I have ordered the revision H ROMs off of eBay just for the sake of having the latest ROM version.
--- End quote ---
It may well be the "D" ROM, I do have one on a CPU board somewhere, but who knows maybe I forgot whether it shows the version or not.
--- Quote ---This is a great idea, but unfortunately I don't have an EPROM reader.
--- End quote ---
You don't need one. You can dump it from MacWorks if you've got a language to write some code in like a C compiler, you can directly access 0x00fe000-0x00fe3fff. I did that early on using ZBasic 5, but that was over the serial port. Shouldn't be too hard to have it written to a file instead.
Might even possible to do that from MACSBUG, though not sure how you'd tell MACSBUG to write something to disk, or maybe TMON.
see:
* https://wiki.preterhuman.net/MacsBug_Howto
* https://tidbits.com/1998/10/05/macsbug-for-the-merely-geeky-part-one/
* https://macgui.com/news/article.php?t=485
* https://macintoshgarden.org/apps/macbug
* https://macintoshgarden.org/apps/tmon
--- Quote ---Unfortunately, I am going out of town tomorrow and I won't get back until Thanksgiving day, so I won't be able to do any more work on the Lisa until then.
--- End quote ---
Happy Thanksgiving, and I'm glad you've got an almost fully working Lisa now.
D.Finni:
--- Quote from: rayarachelian on November 22, 2019, 02:59:53 pm ---You don't need one. You can dump it from MacWorks if you've got a language to write some code in like a C compiler, you can directly access 0x00fe000-0x00fe3fff. I did that early on using ZBasic 5, but that was over the serial port. Shouldn't be too hard to have it written to a file instead.
Might even possible to do that from MACSBUG, though not sure how you'd tell MACSBUG to write something to disk, or maybe TMON.
--- End quote ---
Newer versions of MacsBug, in the 6.x series, can dump to disk, but I don't think these newer versions will run under MacWorks.
AlexTheCat123:
Sorry for the delay in posting. I finally got the chance to install the revision H ROMs that I ordered and now the sound has started working, but the Lisa plays a low-pitched beep (which I believe means CPU or memory error) when it turns on and displays random garbage on the screen. I tried reverting back to the original ROMs and the sound still works, but the same thing happens. I have tried moving the memory boards around and reseating all 4 boards several times, but nothing is fixing the problem. This happened last time I took the boards out as well and I was able to fix it by reseating things several dozen times, but it's not working this time. My guess is that the edge connectors on the boards are intermittent due to me having to repair them with copper tape that begins to deform after lots of insertions and removals. Do you guys have any ideas about a better way to repair these edge connectors on the cards that have been destroyed by the corrosion or would I be better off buying one of these https://www.ebay.com/itm/143185668902 with a pristine edge connector and swapping my CPU and ROMs over to it? I am pretty sure that the CPU board is the problem, not the RAM, because the connectors on the RAM boards were not impacted by the corrosion.
rayarachelian:
--- Quote from: AlexTheCat123 on December 03, 2019, 06:20:16 pm ---Sorry for the delay in posting. I finally got the chance to install the revision H ROMs that I ordered and now the sound has started working, but the Lisa plays a low-pitched beep (which I believe means CPU or memory error) when it turns on and displays random garbage on the screen. I tried reverting back to the original ROMs and the sound still works, but the same thing happens. I have tried moving the memory boards around and reseating all 4 boards several times, but nothing is fixing the problem. This happened last time I took the boards out as well and I was able to fix it by reseating things several dozen times, but it's not working this time. My guess is that the edge connectors on the boards are intermittent due to me having to repair them with copper tape that begins to deform after lots of insertions and removals. Do you guys have any ideas about a better way to repair these edge connectors on the cards that have been destroyed by the corrosion or would I be better off buying one of these https://www.ebay.com/itm/143185668902 with a pristine edge connector and swapping my CPU and ROMs over to it? I am pretty sure that the CPU board is the problem, not the RAM, because the connectors on the RAM boards were not impacted by the corrosion.
--- End quote ---
IMHO, those connectors off ebay are cheap enough that it would be worth buying a few just to have as spares even if you manage to repair the ones there.
They're around $15 each, right, but a new fully populated board would be around $250-$500, so it's worth having them around.
I suppose this is going to suck, but since you have a scope, I'd inject a high freq signal (maybe 10-20MHz?) into one end of a scope using a signal generator in series with the scope, then the other two leads I'd put one on the top side of the connector and one on the same connector's pin at the bottom of the motherboard. If the waveform shows up messed up on that pin likely needs a little help. i.e. something like:
--- Code: --- to-lisa-mobo-pin-bottom<---signal-generator-ground, signal-generator-out-->oscilloscope lead a, oscilloscope-lead-gnd----->to-lisa-mobo-pin-top.
--- End code ---
Before doing that which will likely take about an hour or two, have you tried spraying contact cleaner on the whole connector and then using an antistatic electronics brush (they look like toothbrushes, but black) to clean the whole connector? i.e. brushes like these https://www.amazon.com/Plastic-Portable-Brushes-Cleaning-Keyboard/dp/B074LZ649V/ or (careful with these, you don't want to breathe the dust in and may be overly aggressive to clean metal) https://www.amazon.com/SE-7616SB-Fiberglass-Scratch-Brush/dp/B003NHDITW/ and https://www.amazon.com/MG-Chemicals-Electrosolve-Residue-Electronics/dp/B005DNR0N4/
Would you be able to try removing the copper tape and flowing some solder on top of the contact instead? not much but enough to tin the pin a bit, and maybe hopefully to get rid of corrosion?
It could also be that it's not the connector but the trace underneath is getting eaten by the corrosion.
It could also be something else like one of the MMU registers or connectivity to it has gone bad, and it's not the connector, but since you say you saw the copper tape deforming, than that's likely the root cause.
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