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Author Topic: And so the Lisa adventure begins  (Read 1624 times)

blusnowkitty

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And so the Lisa adventure begins
« on: April 10, 2020, 11:54:48 pm »

Hey all, I just got a 2/5 today that needs a good bit of work, but nothing I don't think I can handle. I spent a good 3-4 hours today rewiring the I/O board to make it all work, and I found some further problems:


- I got two 1.2A power supplies and they both have issues - one will only power the system for a few seconds before they cut off, the other tries to power up but immediately dies. I'll be recapping both of these.
- Sony 400k drive is all gummed up, but that's no surprise. I've been degreasing and relubricating a bunch of these lately so easy fix.
- Base pin on Q11 on the I/O broke completely off. Unfortunately, whatever markings were on the package have long since faded away so I don't know what to replace it with. The other two transistors nearby are both 2N3904s, is that what I need to replace it with?
- When the PSU is cooperating long enough to actually power up the monitor, the image is as if someone rubbed Vaseline all over the screen. I'll be recapping the analog board as well, but while removing that board to get a list of capacitors this trimmer coil (L1 I think) apparently had been getting VERY hot over the years as it crumbled and broke as soon as I bumped it. I did manage to locate it back where it belongs and epoxied what remained of the plastic body back into place, but is this a concern?

Also, what's that on/off switch on the 2/5 I/O board for, anyway? Additionally, while the motherboard did sustain a little corrosion damage as far as I can tell only the exposed pins on the serial port connectors have been affected. The board slots are all in perfect shape.
« Last Edit: April 10, 2020, 11:58:13 pm by blusnowkitty »
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stepleton

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Re: And so the Lisa adventure begins
« Reply #1 on: April 11, 2020, 09:42:33 am »

Congrats on your new 2/5!

Do you know about the schematics available in the documentation section of http://lisa.sunder.net ? They're very handy! I found Q11 also listed as a 2N3904 here:

https://lisaem.sunder.net/LisaSchem/Lisa1SysIO2.gif

(it's at about N3 or N4 in bingo-card coordinates, over toward the right.) These schematics are not Apple originals and and may be revision dependent here and there, but they are also often easier to read than the true schematics here:

http://bitsavers.trailing-edge.com/pdf/apple/lisa/hardware/050-4008-H_IO.pdf

which also lists a 2N3904 on Page 2, straddling cells C1 and C2.

The switch you can find on Page 5 of the true schematics. It disconnects the battery from everything else on the I/O board, but it looks like the battery remains attached to the 5V standby rail on the motherboard and everything downstream from there...

I've never encountered that trimmer coil crumbling myself---maybe someone else has seen this?
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blusnowkitty

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Re: And so the Lisa adventure begins
« Reply #2 on: April 11, 2020, 02:07:30 pm »

Congrats on your new 2/5!

Do you know about the schematics available in the documentation section of http://lisa.sunder.net ? They're very handy! I found Q11 also listed as a 2N3904 here:

Thanks for that, I'm sure it'll come in handy while I'm working on this I/O board. I've got capacitors ordered for the analog board and PSU so I'll get things recapped as soon as I get caps. Is there anything else I need to check out in the 1.2A  PSU besides the caps?

So many patch wires...
https://twitter.com/blusnowkitty/status/1249012854809903105
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rayarachelian

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Re: And so the Lisa adventure begins
« Reply #3 on: April 11, 2020, 03:33:20 pm »

Welcome!

Thanks for that, I'm sure it'll come in handy while I'm working on this I/O board. I've got capacitors ordered for the analog board and PSU so I'll get things recapped as soon as I get caps. Is there anything else I need to check out in the 1.2A  PSU besides the caps?

So many patch wires...
https://twitter.com/blusnowkitty/status/1249012854809903105

The most likely dead caps are going to be the large rectangular semi-see through yellow ones - if you see those, that PSU has never been recapped and must be. Next are the large cylindrical ones. Careful when ordering some of those caps are special - non-polarized and can deal with AC currents. Be sure you've ordered similar caps.

Sometimes the large zener diodes on the PS go bad. Those should be easy to check.
Check the back side of the PS, reflow the solder - the heat can sometimes cause the solder joints to crack.

I'd also remove the memory boards and disconnect the lite adapter (before you do, use a marker to note which end of the cable plugs in) and try to power on the Lisa. This will tell if you if there are shorts.

You can also jam a bit of paper into the front power cut off switch on the bottom left front behind the bezel and thus test with the cover off, and similarly jam a piece of paper into the back of the power supply cut off switch to test with the back off, but I suspect you already know this.
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blusnowkitty

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Re: And so the Lisa adventure begins
« Reply #4 on: April 11, 2020, 06:42:26 pm »

Welcome!

The most likely dead caps are going to be the large rectangular semi-see through yellow ones - if you see those, that PSU has never been recapped and must be. Next are the large cylindrical ones. Careful when ordering some of those caps are special - non-polarized and can deal with AC currents. Be sure you've ordered similar caps.

Sometimes the large zener diodes on the PS go bad. Those should be easy to check.
Check the back side of the PS, reflow the solder - the heat can sometimes cause the solder joints to crack.

I'd also remove the memory boards and disconnect the lite adapter (before you do, use a marker to note which end of the cable plugs in) and try to power on the Lisa. This will tell if you if there are shorts.

You can also jam a bit of paper into the front power cut off switch on the bottom left front behind the bezel and thus test with the cover off, and similarly jam a piece of paper into the back of the power supply cut off switch to test with the back off, but I suspect you already know this.


I'm well aware of how bad the Rifa caps are. I was working on a project with both my Mac 128 and 512ke plugged up and all the Rifas in both of  those decided to blow at the same time, it was not fun... So yeah, I'm pulling the Rifas as soon as I get capacitors in. Right now I'm just focusing on the electrolytics and the Rifas but I'll replace other caps and parts if need be, thanks.

I've also noticed that with the power supplies as they are now, using the semi-working one I can usually only get one or two power-up attempts out of them - one lasts just long enough to bring up the POST screen and shows errors, the other only lasts a second or two before it shuts off. The completely dead power supply I can usually get it to click a bit and power off instantly. In both cases it usually takes several hours for whatever's inside to allow me another power-on attempt. Very strange... But, can't do any real testing 'til I get everything recapped.

On another note, Ray, I blame you for getting me into Lisas in the first place. I was watching LisaEm's progress for a year or two prior to the very first working build of the emulator :D
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rayarachelian

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Re: And so the Lisa adventure begins
« Reply #5 on: April 11, 2020, 08:19:55 pm »

The completely dead power supply I can usually get it to click a bit and power off instantly.

That's a classic symptom of bad caps right there.

In both cases it usually takes several hours for whatever's inside to allow me another power-on attempt. Very strange... But, can't do any real testing 'til I get everything recapped.

On another note, Ray, I blame you for getting me into Lisas in the first place. I was watching LisaEm's progress for a year or two prior to the very first working build of the emulator :D

Indeed, fix the caps, that's the first step.

Oh, and uh, you're welcome.
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patrick

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Re: And so the Lisa adventure begins
« Reply #6 on: April 12, 2020, 08:38:20 am »

Check the 5 V setting pot (R29, 500R) on the power supply board. If the slider loses contact with the cermet track, the output voltages will increase until they trip the crowbar thyristor. This can happen once after warming up (power supply simply switches off) or frequently (power supply makes clicking noises).

As mentioned above, the golden RIFA capacitors usually need to be replaced. Use X2 resp Y2 parts to comply with your local safety regulations. The power supply also works without these parts, but EMI will be above CE resp. FCC limits.

Of course, electrolytic capacitors can fail after some time, just like any other component. But with THT electrolytes from the 80s there is definitely no need to replace them prematurely. The quality of these parts is much better than "consumer grade" components you can buy today. If something needs to be replaced after all, use components from well-known manufacturers (like Nichicon, Panasonic, Nippon Chemicon, Elna...), buy them from a reliable dealer who can give the exact type designation (no Chinese mail order!), and check the specifications in the manufacturer's data sheet. In this way you will achieve a service life of about 10 - 20 years again.

(SMD electrolytic capacitors from the '90s are a different issue. Some series, like the ones used in the Mac II family, in Tektronix testgear or Sony Hifi equipment, tend to spill and must be replaced now!)

Elcaps from the '80s and before lose their dielectric oxide during storage. This results in an increased leakage current, but can be cured by running it at its rated voltage for some time. Parts from the '90s and later have oxidizing electrolytes. They do not degrade during storage, but if they leak damage to the PCB tracks will occur.



To force the power supply on, connect the ON signal to +5Vstby. On the PSU connector ON is pin X and +5Vstby is pin 20. For standalone operation you will need some load at +5 V and +12 V, an automotive headlight bulb works fine for the 5 V rail, and a 5 W lamp is sufficient for the 12 volts. To build a test rig, get a "JAMMA Arcade" board edge connector from ebay and cut it to the required length.

To force power-on from the Lisa I/O board, bend U9F pin 24 out of its socket (or remove the COPS421 completely) and connect U7F pin 11 to the standby voltage (U9F pin 9).


One electrolytic capacitor that frequently fails is C8 on the CPU board. If it has an increased leakage current, the reset generator hangs and with it your Lisa, she shows a random pattern on the screen. The capacitor can be replaced or, if you want to leave the board in its original state, it can be regenerated by connecting it to its rated voltage for a few hours with a 10k current limiting resistor.



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blusnowkitty

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Re: And so the Lisa adventure begins
« Reply #7 on: April 12, 2020, 12:22:21 pm »

-snip-

I'll check it out and I'll give that thing a healthy dose of Deoxit once I get my capacitors in. And don't worry, I've specced out exact replacements for both the analog board and power supplies, all of which are high-temperature Nichicons. No generic capacitors here! I agree with your point on not replacing capacitors prematurely, but these are getting on for nearly 40 years old and with Jobs hating fans I'm sure they've had a pretty rough life... Probably guaranteed that they've had a rough life if that burned up trimmer coil is anything to go by.

Interestingly, my COP421 chip is actually soldered in place on the I/O board and not socketed. I have been able to test the power supplies as far as putting out the correct standby voltage and I can verify that voltage is getting to the COP421. During some additional probing last night I found that both PWRSW and ON in the schematic aren't making it to the COP421 at all so I'm guessing that's one reason why this thing is so hesitant to power on. Time for more patch wires!

Am I correct in thinking that the COP421 is pinned out like so?

Code: [Select]
|--------------|
|24          13|
|    COP421    |
|1           12|
|--------------|

« Last Edit: April 12, 2020, 12:29:48 pm by blusnowkitty »
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blusnowkitty

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Re: And so the Lisa adventure begins
« Reply #8 on: April 15, 2020, 04:21:13 pm »

Capacitors came in today. I recapped the analog board and one of my two power supplies. Plugged everything back in and... absolutely nothing. Case interlocks were bypassed; I made a quick modification to the IO board to bypass the COP421 and still nothing.Switching out for the one I haven't recapped but was able to power the system before, and it's also dead. Currently the only things connected are the CRT and its electronics, the I/O board, and the CPU board. RAM, LisaLite, and Sony 400k drive are all disconnected.


At this point I'm not sure if it's the I/O board or that both power supplies have failed simultaneously, but with as much corrosion and rework as I've had to do to the I/O board I'm leaning on the former. I've put in for a Sapient repro so I'll be fitting that with my recapped supply when it comes in and I'll see what happens.
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patrick

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Re: And so the Lisa adventure begins
« Reply #9 on: April 18, 2020, 08:12:44 am »

Capacitors came in today. I recapped the analog board and one of my two power supplies. Plugged everything back in and... absolutely nothing. Case interlocks were bypassed; I made a quick modification to the IO board to bypass the COP421 and still nothing.Switching out for the one I haven't recapped but was able to power the system before, and it's also dead.

Before spending money on replacement boards, make sure that the PSU will start when ON is applied and that it puts out the proper voltages.

Make a test fixture and check the power supplies alone before putting them into the Lisa. Connect automotive lightbulbs to the +5V and +12V rails to provide some load and visible indication. Connect +5VSEN (N) to the +5V rail. Apply power and check if +5VSTBY (20) is there. Then connect ON (X) to +5VSTBY and check the other voltages for amplitude and ripple. If excessive ripple is present, one or more capacitors need to be replaced. 

If one voltage is shorted (e.g. by an broken rectifier) you will see the others starting up for a few milliseconds before shutting down.

Tap the voltage alignment pot (R29) inside the PSU and check if the voltages remain stable. If this causes spikes, replace the pot.


Corrosion usually affects the mainboard, too. It might be necessary to replace the I/O board connector, and of course to check the PCB tracks itself. Connectors might look good but have pins rotten off on the bottom. This is not visible until you desolder the connector.
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blusnowkitty

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Re: And so the Lisa adventure begins
« Reply #10 on: April 18, 2020, 11:32:09 pm »

So I actually got things in a slightly better shape a few days ago but I didn't want to triple-post.

I must have gotten some jumper wires mixed up somewhere along the line. I pulled off all the jumper wires except for the one going from the 7417 to the COP421 and then the Lisa actually started to power up again. The recapped supply was still clicking but I gave R29 a dose of Deoxit and tweaked the pot and so far it's been going alright. I also figured out that whatever was going on with that burned coil probably hasn't hurt it too bad as tweaking and throwing some Deoxit in all the video pots got the video more or less working. I am now having an issue with the screen being "wobbly" - turns out someone else on 68kmla is having the exact same issue: https://68kmla.org/forums/index.php?/topic/59382-lisa-ac-interference-coupling/

As far as the I/O board goes - thankfully the COP421 appears to be working as even though I bypassed its soft power ability, I'm still getting mouse and keyboard input. However, disk access isn't working as I'm getting lots of Error 39 and Error 57 messages on POST. I also noticed that with the original drive ROM the Lisa would sometimes identify it correctly as A8, but more often than not wouldn't read it properly and throw any random hex value from 00 to FF up on the screen. I replaced the ROM with one I burned from Bitsavers and now it's reading it as A8 every time, but I'm still getting 39 and 57 errors. All socketed ICs were removed and sprayed with Deoxit just to be on the safe side and there's been no difference. I've also noticed that with either drive ROM a lot of times the Lisa will think it's somehow become a Twiggy machine again and will show two floppy drives in the startup menu, even though I'm running F/A8 or H/A8 (I have both). Finally as a further troubleshooting aid I hooked up my Floppy Emu in Lisa mode and I've discovered that most of the time the Lisa will make absolutely no attempt to read a disk. Sometimes during POST, however, the Lisa will pull the Read line active but it still makes no effort to actually read a disk.

Motherboard-wise, I also hit it with Deoxit just to be on the safe side but my motherboard surprisingly it was largely spared from battery damage as all the I/O board contacts and solder joints have perfect continuity everywhere they're supposed to go.

I'm sure it's probably a case of corroded traces causing the disk access issue, but as I have no test equipment besides a basic Hazard Fraught Tools multimeter, I thought it would be better to get a known good I/O board to work with. Later on I can come back to the original I/O board once I have better test equipment and take a real deep dive into exactly what's going on.
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blusnowkitty

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Re: And so the Lisa adventure begins
« Reply #11 on: May 01, 2020, 03:09:39 pm »

New I/O board came in today and here's where things get interesting. Plugging the new I/O board in causes the built-in monitor to stop displaying an image, but I get an image off the video out port. Plugging the old I/O board in causes the built-in monitor to work again. Any tips on what I should check out?

As it turns out I'm the idiot here - I forgot I adjusted the analog board's contrast level for the old board and it wasn't right for the new board.

Now I'm trying to figure out why the floppy isn't reading correctly. On both a known good 400k drive and a Floppy Emu it'll make some attempt to read the floppy (or format) but it eventually just gives up and says there was an error. I also can't get BLU going again so that's fun.

Update: Now I got BLU to load. If I try to format a floppy, I get Error 15 from the controller. If I try to read a disk into memory, I get Error 17.
« Last Edit: May 01, 2020, 06:26:37 pm by blusnowkitty »
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blusnowkitty

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Re: And so the Lisa adventure begins
« Reply #12 on: May 03, 2020, 11:21:22 pm »

One more little update here... It appears to be fully working electrically now! Just had to reseat some chips and I got serial and the floppy drive working. Here's the rundown of what I've done to get it up and running:

- Installed new I/O board (Would have redone the old one, but I lack the necessary tools to do a deep investigation into it)
- Installed X/ProFile
- Recapped PSU
- Recapped analog board, plus resoldered all the joints as something was dry and causing video glitches
- Heavy dose of Deoxit in the analog board pots to clear up the contrast smeariness
- Disassembled and relubed floppy drive

All in all a fairly easy job, just time-consuming. Now I have a fully working 2/5 running Office System 3.1 with the full suite of LOS Apps, plus the third-party Phone Dialer (what's it even dialing, anyway?), Calendar, and LabeList. Any more Office System software out there?
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stepleton

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Re: And so the Lisa adventure begins
« Reply #13 on: May 04, 2020, 10:28:17 am »

There aren't many Office System apps out there. The Lisa was designed with the idea of giving its buyers most of what they needed in one go---at least, I seem to remember Larry Tesler saying something like that in this video.

This didn't stop people from making a few apps here and there. Some of them are on bitsavers.

If you'd like to explore the Mandelbrot set very, very slowly, you can try out my LisaMandelbrot program. This has been written using the QuickPort library, a convenience library for turning full-screen Lisa programs that usually run in the Workshop into applications that can run under the Office System. As such, it's not very good.

If you're really feeling ambitious, you could try writing your own full-featured app using the Lisa ToolKit. The ToolKit (documentation here and here) even comes with about a dozen example apps that demonstrate some of the ToolKit's features and operating principles. They're not all that interesting, but one of them is a little piano keyboard that makes little beeps, which is fun...
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blusnowkitty

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Re: And so the Lisa adventure begins
« Reply #14 on: May 07, 2020, 09:49:28 am »

ToolKit seems fun; I've been trying to figure out how to get that to install properly in LisaEm for a little bit. I figure the Lisa and my Mac 128 is a good place to get to grips with 68000 assembly, and I've been working with C# enough to kinda get OOP; Lisa Pascal/Clascal just seems like a more archaic form of that.

I have some big plans for this thing...
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