Reconstructing an auctioned Lisa

[TorZidan]

CRT televisions and monitors can cause serious injury or death, even when unplugged for days, weeks, or months. Read and follow all precautions before opening any CRT device.

LETHAL HIGH VOLTAGE

The anode (high-voltage) circuit can hold 20,000-30,000+ volts on the tube's second anode, the suction-cup connector on the glass.
Capacitors, including the tube itself, can retain a dangerous charge long after power is removed.
Flyback transformers and the associated circuitry can also deliver painful or dangerous shocks.

IMPLOSION HAZARD

The glass envelope is under vacuum and can implode violently if cracked, scratched, or struck.
Flying glass can cause severe lacerations and eye injuries.
Never carry a tube by its neck. Never apply pressure to the neck or the neck board.
Wear safety glasses or a face shield at all times.

BEFORE YOU BEGIN

Unplug the device from mains power.
Work only if you are trained or experienced with high-voltage electronics. If you are not, do not open the case.
Never work alone. Have someone nearby who can call for help and knows CPR.
Keep one hand in your pocket or behind your back when probing live circuits, to avoid a path across your chest and heart.
Remove jewelry and metal accessories.
Work on a dry, non-conductive surface. Keep liquids away from the work area.

DISCHARGING

Discharge the anode only with a properly insulated, high-voltage discharge tool and a known-good ground connection, following the correct procedure for your specific device.
Never use a bare screwdriver or improvised tool. This can damage components and injure you.
Do not assume the tube is discharged. Verify with an appropriate high-voltage probe.
Recharging can occur after discharge (dielectric absorption), so re-check before touching.

[berskyboy]

CRT televisions and monitors can cause serious injury or death, even when unplugged for days, weeks, or months. Read and follow all precautions before opening any CRT device.

hi TorZidan, yup it came unplugged and the CRT was even upside down.  I'm still working bench testing the PSU.  So no power as of yet.  And could have been for a decade or so , but yes I made a screwdriver with an alligator clip and have discharged few vintage CRTs (NeXT Monitor, Mac SE). 

My question was regarding what AI said, and I'm wondering if I'm missing any parts.

https://youtube.com/shorts/K4iUFtFl23A

[sigma7]

I made a screwdriver with an alligator clip and have discharged few vintage CRTs (NeXT Monitor, Mac SE). 

For the benefit of others, that would be a "sufficiently insulated" screwdriver, as a few KV will go through the otherwise insulating handle of many screwdrivers. This kind of non-obvious detail is why the warning specifies "Work only if you are trained or experienced with high-voltage electronics." Working around the CRT is dangerous: proceed at your own risk!

Also, the alligator clip is typically wired through a high value resistor so the current surge is limited.

Note that the high voltage of the CRT stinger will damage/destroy a DMM unless a working high voltage probe is used properly. According to the video board schematic, the Lisa CRT HV is 13KV (and may be higher if there is a fault in the circuitry). DMMs are typically limited to 1KV, some much less.

the CRT was even upside down.

An upside down CRT might be intended as a warning sign. You've found quite a project!

My question was regarding what AI said

It is good you asked. It looks like AI has led you astray a couple of times already, so we should all take its responses as "concepts to investigate" rather than "directions to follow" as worded.

The black coating/paint on the CRT should have a low resistance to the chassis. This connection is made (on some Lisa CRTs at least) via a flat copper spring loop at one side of the CRT. (Different from what AI said it would be)

If the spring isn't there, and you don't have a low resistance from the chassis to the black conductive dag coating, then indeed some other connection is needed.

and I'm wondering if I'm missing any parts

In your video, I see a Widget hard drive (above the floppy drive), which if still working, you probably don't want to use since a modern emulator will give better performance, be more convenient, and preserve what life is left (if any) in the Widget.

The Widget does not have a power or data cable connected. What are the cables in that area that are not connected?

Given the other oddities, I wonder if you have a full wiring harness... check if there is a card edge connector for the PSU to plug into, another for the motherboard to plug into, and another for the video card to plug into. There should also be a connector plugged into the flyback transformer, the other ends of the thin green and white wires, and wires going to the speaker behind the front panel safety interlock switch. And finally, another (non-ribbon cable) connector in the drive cage area (there are two different types, depending on the type of wiring harness).

You may/probably need to clean and re-lubricate the 400K Sony drive if you wish to use it.

[berskyboy]

I made a screwdriver with an alligator clip and have discharged few vintage CRTs (NeXT Monitor, Mac SE). 

It is good you asked. It looks like AI has led you astray a couple of times already, so we should all take its responses as "concepts to investigate" rather than "directions to follow" as worded.

The black coating/paint on the CRT should have a low resistance to the chassis. This connection is made (on some CRTs at least) via a copper wide spring loop at one side of the CRT. (Different from what AI said it would be)

If the spring isn't there, and you don't have a low resistance from the chassis to the dag coating, then indeed some other connection is needed.

So I'm not 100% certain what I'm looking for here, here's another look at the CRT

https://www.dropbox.com/scl/fi/e73juylm4yrwcdzws1lj6/Lisa-CRT.HEIC?rlkey=2nnsz4katm1txogbylds112kz&st=1lzh311w&dl=0

And I did created a 60 pin cable after watching Adrian's YouTube Video.

https://www.dropbox.com/scl/fi/fss0cuwubwnschhmr5564/Recreated-Ribbon.HEIC?rlkey=f5fkgyglxtyuvj0dl7lh3i2bn&st=ohtg7269&dl=0

[sigma7]

The black coating/paint on the CRT should have a low resistance to the chassis. This connection is made (on some CRTs at least) via a copper wide spring loop at one side of the CRT. (Different from what AI said it would be)

So I'm not 100% certain what I'm looking for here

1. Use the DMM to measure the resistance from the black paint (on the CRT) to the silvery metal chassis.

2. Look around the perimeter of the CRT for a copper coloured flat spring that goes between the CRT and the silvery metal chassis.

[sigma7]

CRT televisions and monitors can cause serious injury or death

Thanks for posting this warning; I'll repost it to the Troubleshooting area.

[berskyboy]

1. Use the DMM to measure the resistance from the black paint (on the CRT) to the silvery metal chassis.

2. Look around the perimeter of the CRT for a copper coloured flat spring that goes between the CRT and the silvery metal chassis.

Here's a video with my measurements using DMM

https://www.youtube.com/shorts/ixwfd6GJof0

[sigma7]

1. Use the DMM to measure the resistance from the black paint (on the CRT) to the silvery metal chassis.

2. Look around the perimeter of the CRT for a copper coloured flat spring that goes between the CRT and the silvery metal chassis.

Here's a video with my measurements using DMM

A couple of hundred ohms seems plausible, depending on where you probe the conductive coating.

So that may mean the copper flat spring is in place somewhere, possible at the right side where the chassis is very close to the tube. If you can find it, please post a picture for reference by future troubleshooters.

[stepleton]

An upside down CRT might be intended as a warning sign. You've found quite a project!

Fun fact: rotating the CRT 180 degrees was a (recommended) regular maintenance item for Tektronix 4050-series vector storage display computers, intended to preserve the life of the storage CRT. I don't think many people actually did it, and for the 4054 and 4054A, you probably would have wanted an engine hoist to help out with the job.

[berskyboy]

Congrats and you're welcome. Thanks for your help testing this process!

Honestly Sigma7 you are a rock star!

I have another question for you when I tried to turn it on.  There is no front bezel switch and there is two wires green and white.  If I connect those would that by pass the front bezel switch?

front bezel:
https://www.dropbox.com/scl/fi/dv3w4s45edq6qx885x9ba/No-front-bezel.HEIC?rlkey=k8kkzbjpjgj1k7b9b6ghuykue&st=3kkh57q4&dl=0

two wires:
https://www.dropbox.com/scl/fi/lgmzu07e6eve7dusb7v0t/White-Wire-goes-to-Red-Circle.jpeg?rlkey=0wxa7j8uncfm485z00tj1p9ht&st=r2oodyg8&dl=0

[sigma7]

A long thread "Adventure in fixing a Lisa DataPower PSU" was split off from this thread at this point.

I have another question for you when I tried to turn it on.  There is no front bezel switch and there is two wires green and white.  If I connect those would that by pass the front bezel switch?

The green and white wires under the left side of the CRT go to the front panel safety interlock switch, which is missing in your picture (along with the plastic holder).

IIRC, connecting them would have the effect of preventing turn-on, and so you want them disconnected if there is no interlock switch to activate.

[berskyboy]

The green and white wires under the left side of the CRT go to the front panel safety interlock switch, which is missing in your picture (along with the plastic holder).

IIRC, connecting them would have the effect of preventing turn-on, and so you want them disconnected if there is no interlock switch to activate.

OK so leaving it disconnected and making sure the back connector on the PSU is engaged (or the back cover is on), there should be life. 

There isn't but I think I need to watch Adrian's videos and again and check the cable I made to the motherboard.  I made a 60pin cable.  Is there another way to test it by passing the on button/or soft switch?

Do you recommend doing a bench controlled testing like Adrian has done also?

[sigma7]

OK so leaving it disconnected and making sure the back connector on the PSU is engaged (or the back cover is on), there should be life. 

There isn't but I think I need to watch Adrian's videos and again and check the cable I made to the motherboard.  I made a 60pin cable.  Is there another way to test it by passing the on button/or soft switch?

Do you recommend doing a bench controlled testing like Adrian has done also?

Normally, a Lisa will power up if you plug it in with the I/O Board missing, so you could try that first. (It won't run normally of course, but there will be signs of life.)

I'm not sure I know what you mean by "bench controlled testing", but given the adventure with the PSU, I recommend working on this Lisa complete rather than working on it apart.

Perhaps you should start by posting pictures of what you have, including:

• The 60 pin cable you made, showing all connectors
• Which motherboard you have
• Which I/O Board you have

edit: I see now that a while ago it was established that you have a Lisa 1/5 motherboard and 2/10 I/O Board. We should still review what cable you've made.

[berskyboy]

Normally, a Lisa will power up if you plug it in with the I/O Board missing, so you could try that first. (It won't run normally of course, but there will be signs of life.)

I'm not sure I know what you mean by "bench controlled testing", but given the adventure with the PSU, I recommend working on this Lisa complete rather than working on it apart.

Perhaps you should start by posting pictures of what you have, including:

• The 60 pin cable you made, showing all connectors

[/list]

Here's a few photos of the cable that I made following what Adrian's Basement videos showed

https://www.dropbox.com/scl/fi/kdqdkmva3xj13tmifhd8z/IMG_3480.jpeg?rlkey=vswnxhj2fmnnebfebfy4c7uhw&st=q8wpzkxp&dl=0

https://www.dropbox.com/scl/fi/jrlrna9nh1znw2jlrm0p1/IMG_3811.jpeg?rlkey=fxr1d0j6dhl8ct2tr6sqabhs3&st=ahcxnigj&dl=0

https://www.dropbox.com/scl/fi/djxyem64bql41xh7lrpd6/IMG_3812.jpeg?rlkey=gylliz4h4592g3tdtgdc08f4a&st=op7e0vmt&dl=0

https://www.dropbox.com/scl/fi/igjy89juib3ivkkbwaigy/IMG_3813.jpeg?rlkey=kvosr84z1su75pgahy54u4r73&st=xibt4bg6&dl=0

https://www.dropbox.com/scl/fi/e198f1gqd9p9f2cqbo4pp/IMG_3814.jpeg?rlkey=e3zv44p7270fn5xekb4ebox8d&st=dmqjmw0e&dl=0

EDIT: AI said this, which might be correct. 
"Looking closely at your photos, you have made a classic, very easy-to-make mistake when crimping a new ribbon cable. Your IDC10 connector is mirrored / flipped 180 degrees backwards. Here is the exact visual proof from your photos and how to fix it so your Lisa can finally boot."

I was trying my best to line up things as Adriane had done it.  But is this correct?

[sigma7]

Normally, a Lisa will power up if you plug it in with the I/O Board missing, so you could try that first. (It won't run normally of course, but there will be signs of life.)

EDIT: AI said this, which might be correct. 
"Looking closely at your photos, you have made a classic, very easy-to-make mistake when crimping a new ribbon cable. Your IDC10 connector is mirrored / flipped 180 degrees backwards. Here is the exact visual proof from your photos and how to fix it so your Lisa can finally boot."

I was trying my best to line up things as Adriane had done it.  But is this correct?

Did you tell AI that it is a Lisa chassis cable? It seems to think it is a generic one.

That part of the cable looks ok to me, but perhaps you should use your DMM to confirm a couple of signals on the keyboard jack/power button board go to the correct pins on the motherboard's I/O Board socket.

Can't see other connectors on the ribbon cable, so might not be appropriate for the mixed Lisa 1/5 and 2/10 I/O Board configuration.

I do see a Widget power connector, so that makes it a 2/10 chassis originally FYI.

Does it power up with the I/O Board removed?