Thin Neck Thanksgiving- Luke Cave Found Parts Revealed!

DaveP

Master Member
RPF PREMIUM MEMBER
Thank you for your feedback and comments!

I already did an IC blast on the LC-785B board I didn't need a few months ago, and although I can clearly see the damage marks on the upper left corner of the IC on the hero board, I don't think they were successful.

The IC was glued with Death Star brass as an ornament for the visual concept, and the bottom was painted with white paint. The IC on the board is so thin that it will crumble to pieces with the slightest pressure. The upper left corner of the prop board has the solder marks I often see on the 785 board. I believe it's original.

I have taken some images for you so you can see what the inside of the IC looks like after it has been destroyed.

Thanks also to thd9791 for his contribution to the blasting treatment of other similar Casio calculators IC in his possession.(y)

View attachment 1644847

As a result, I received a new 785A/3 calculator yesterday to match this anomalously colored 785A/2, and I still believe that the color of the board is the key to matching our Hero board. [I'm still having bad luck:(] Since it's very difficult to get a 785A calculator now, not to mention my desire for A2 board, So now my progress has become very slow.

If I find out later that the colors of A1 and A3 boards are very close to the colors of this A2 calculator, I will take back what I said before.:)

View attachment 1644848
Your work on this is outstanding, Poikilotherm! The colour difference on your A2 board is quite striking!

So far, I've only been lucky enough to find two A variants. This A3 (which I based my new design on):

PXL_20211101_111211047.jpg

PXL_20211101_111228153.jpg

PXL_20211101_111240751.jpg


And this, my most recent find (an A1):

PXL_20221128_101304142~2.jpg


Obviously, different cameras/lighting, etc will produce different results, but this latest A1 actually looks quite similar to your A2, Poikilotherm. This is the raw image for comparison.

I'm wondering (in fact I suspect) that the colour differences are down to the thickness of the solder mask rather than the actual colour of it (especially the perceived colour of the traces). I agree that age plays a part though too.

Anyway. Just sharing for comparison.

I haven't dared remove this one yet to see the front. It's still fully functional, and getting everything back together as it was can be a bit of a pain.

It just goes to show though, that you can get lucky still. This one popped up completely out of the blue with a "buy now" on it (which I did of course!!!). It's safe to say though, after a year of looking with very few people knowing about them... They're as rare as hen's teeth! :

PRECIOUS.jpg
 

Poikilotherm

Sr Member
Yeah, I was thinking that it may have even been inverted and the switch head was glued to the lower board making the cutout PCB the new switch "head"/lever. With the red wires seemingly come out from beneath it, it would have been a wonderfuly creative work around.

What IS on the other side of that little chunk of PCB?

Lower right hand PCB in Poikilotherm's pic here with the longer red arrow pointing to it...
View attachment 1645213

Anything special there? Just curious since I don't have a 785 yet.
There is solder on there and I see multiple silver wires on the Hero board. From what I know of the Hero board so far, perhaps the Hero control box circuitry is powered by flying wires soldered to the brass on board 785 to drive the components inside the control box.

As for the rest of the 785 accessories, I was discussing with Tom a few days ago about whether the two 1.5V original 785 batteries could be put into the control box, and yes, they can be put into the control box and powered, they just need a double layer of battery tabs. I also did a quick drawing a few days ago of a haphazard connection schematic to get the components in the control box powered up via the brass flying wires on the 785 board.
20221207141510.png

Since our town has just been decontrolled, the town has just returned to normal order, and courier shipping service has not been fully restored, it will take me a while to re-solder the 785 board and bring the 785 back to life like a zombie.:)

As for the red led switch inside the control box, it must be a momentary cut-off switch, the main switch is an exactra 19 series switch, the sound of Mark Hamill using tools to press the red switch in the deleted clip has been handled behind the scenes, we can still hear the popping sound when Mark Hamill tries to deflect the switch.
20221207152023.png
20221207173248.png


This is the clearest video I can give you of the red led switch after it is triggered. In fact, you can see that the contact needle of the tool is very thin and very short, and I will explain why below.


I currently have no plans to trim my No.152 tool, the tool I used in the series of videos I recorded was just a visual feedback concept study tool I made for Bryan last December that I've been using ever since. On the eve of these amazing news going public, I did a final visual check of the cave footage and I thought if we had a chance to see some behind-the-scenes photos of the crew holding the ballpoint pen, we could locate the vintage ballpoint pen and then make final changes to the 152 nozzle.[Here's my personal understanding, and here's what I'll eventually do.]

Bryan also mentioned the possibility of a ballpoint pen tip on the first page of the thread. ;)

20221207140052.png


For the matrix, we haven't found the correct vintage matrix yet, at least I don't see the top guide hole in the modern matrix, I think Roy will take care of these things. I don't have much more energy to add to the tool and matrix search queue at this time.:)

20221207140809.png
 
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Poikilotherm

Sr Member
Your work on this is outstanding, Poikilotherm! The colour difference on your A2 board is quite striking!

So far, I've only been lucky enough to find two A variants. This A3 (which I based my new design on):

View attachment 1645221
View attachment 1645222
View attachment 1645223

And this, my most recent find (an A1):

View attachment 1645224

Obviously, different cameras/lighting, etc will produce different results, but this latest A1 actually looks quite similar to your A2, Poikilotherm. This is the raw image for comparison.

I'm wondering (in fact I suspect) that the colour differences are down to the thickness of the solder mask rather than the actual colour of it (especially the perceived colour of the traces). I agree that age plays a part though too.

Anyway. Just sharing for comparison.

I haven't dared remove this one yet to see the front. It's still fully functional, and getting everything back together as it was can be a bit of a pain.

It just goes to show though, that you can get lucky still. This one popped up completely out of the blue with a "buy now" on it (which I did of course!!!). It's safe to say though, after a year of looking with very few people knowing about them... They're as rare as hen's teeth! :

View attachment 1645226

It's true, different lighting and phones give different results, and assuming the A1 model you just found has basically the same color as my A2 model, I think you'll adjust the color on your upcoming replica board.

I also previously owned an A1 model. Now that it has been trimmed, my A1 model is a much better color than the 3 A3 models I have found now, just very close, but still very different from the A2. The A2 plate already looks like it has a blue filter on it.
[I don't know how to answer this, and I'm not sure if this is a process problem or if all A2 series are like this:(]

I'm just getting involved in the board discussion as a researcher, and I think I can live with whatever color you end up releasing.;)

[No one can tell the color of the board when recording video in a dark room, he's pitch black! The whole time the focus was on the flickering part!]:D

For the explanation of the solder resist layer I think it is possible. But first we need to see more A1/A3 close to the A2 color, at least it is not the 3 A3 type light green that I have. At least with the A3 light green I had a hard time matching the Hero board color accurately through Photoshop, only the A2 I currently have can.

20221207144137.png


My 3 A3 model 785 calculators are by far the most unacceptable plate color I think I have, at least all 3 of my A3s are light green.
Since I can't share that clearer image, I can use this grid image of my unacceptable A3 plate color on the right, the green line no matter how I use the post-processed color, it doesn't come close to the Hero plate with my A2 plate post-processed image.
At least I can be sure that the green line at the position of the arrow in the other high-resolution image is not light green.
The blurred Hero plate on the left side is not visible.
20221207143413.png

202212072025322.png


This is a Photoshop image, but of course this is all for research purposes only and does not bring any benefit to any 785A calculator, all 785A calculators are the same.:D

20221207174500.png


When I first saw the image of your replica board, I guessed that your board must be A3, and it was. Only A3 I can see that earthy green color. I'm still hoping that the color will be the same from the factory and that it will fade over the decades due to oxidation. Obviously we need more 785A/1/2/3 to verify these claims.

At the moment I still think that the plate can still be Photoshop to get a plate color very close to Hero's plate with a blue filter, as long as the plate is not a light green line 785A.


20221207145928.png
 
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thd9791

Master Member
RPF PREMIUM MEMBER
There is solder on there and I see multiple silver wires on the Hero board. From what I know of the Hero board so far, perhaps the Hero control box circuitry is powered by flying wires soldered to the brass on board 785 to drive the components inside the control box.

As for the rest of the 785 accessories, I was discussing with Tom a few days ago about whether the two 1.5V original 785 batteries could be put into the control box, and yes, they can be put into the control box and powered, they just need a double layer of battery tabs. I also did a quick drawing a few days ago of a haphazard connection schematic to get the components in the control box powered up via the brass flying wires on the 785 board. View attachment 1645314
Since our town has just been decontrolled, the town has just returned to normal order, and courier shipping service has not been fully restored, it will take me a while to re-solder the 785 board and bring the 785 back to life like a zombie.:)

As for the red led switch inside the control box, it must be a momentary cut-off switch, the main switch is an exactra 19 series switch, the sound of Mark Hamill using tools to press the red switch in the deleted clip has been handled behind the scenes, we can still hear the popping sound when Mark Hamill tries to deflect the switch. View attachment 1645341 View attachment 1645350

This is the clearest video I can give you of the red led switch after it is triggered. In fact, you can see that the contact needle of the tool is very thin and very short, and I will explain why below.
View attachment 1645309

I currently have no plans to trim my No.152 tool, the tool I used in the series of videos I recorded was just a visual feedback concept study tool I made for Bryan last December that I've been using ever since. On the eve of these amazing news going public, I did a final visual check of the cave footage and I thought if we had a chance to see some behind-the-scenes photos of the crew holding the ballpoint pen, we could locate the vintage ballpoint pen and then make final changes to the 152 nozzle.[Here's my personal understanding, and here's what I'll eventually do.]

Bryan also mentioned the possibility of a ballpoint pen tip on the first page of the thread. ;)

View attachment 1645310

For the matrix, we haven't found the correct vintage matrix yet, at least I don't see the top guide hole in the modern matrix, I think Roy will take care of these things. I don't have much more energy to add to the tool and matrix search queue at this time.:)

View attachment 1645311

Well I guess I have to take a drill to my matrix retainer now…

Such a cool detail!!!
 

v312

Sr Member
Few thoughts on the circuit. To be historically correct it should probably use simple LEDs and not self blinking ones. Please correct me if I'm wrong, but from memory they started to appear after the simple blue ones were common, so it should be well after 1983.
So I think some simple circuit based on transistors or a 555 was used. A circuit from a battery powered (like quartz) watch or clock from that era should be able to be repurposed for this as well ... (would be really cool if the reveal board itself can be wired to generate the pulse)

Regardless of what circuit is used to generate the blinking signal, my theory is that to switch from the green to the red led a simple on/off momentary switch was used, or even no switch at all, but maybe 2 traces were shortened with the tool itself (as it is the same thing).
Basically, if you have a red and a green diode in parallel the green one should stop emitting as soon as you connect the red one. It's the simplest way to do that I can think of and the one that should take least space

Here's a 555 based one that I found online, I've only added the red diode and the switch to show what I mean:

1670608461823.png

1670608519265.png


For the actual reveal board it would be really interesting to nail which version it was. But other than the little number so far I've not noticed any other difference. Traces seem to be identical, as well as the few components and the chip. By the way the date code on the chip if it is the same as what Toshiba used on some other components should be "year - month" so 0 should be 1980 , 1 is 1981, A = Jan, B = Feb , etc.
 
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BRRogers

Master Member
RPF PREMIUM MEMBER
555’s have been mentioned before- I just haven’t seen them wired yet, although the size does seem like it could be smaller itself.
(Electronics diagrams are unfortunately basically jibberish to me)
It requires a slew of other components does it not?
 

v312

Sr Member
555’s have been mentioned before- I just haven’t seen them wired yet, although the size does seem like it could be smaller itself.
(Electronics diagrams are unfortunately basically jibberish to me)
It requires a slew of other components does it not?
There should be enough space. Besides the 555 it only needs 3 resistors and a capacitor. Here is what this should look like size wise (these are not the actual component values and are not wired - I just picked some from the junk box with the same size to arrange for a quick shot).
1670627578470.png
 
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Halliwax

Legendary Member
RPF PREMIUM MEMBER
There should be enough space. Besides the 555 it only needs 3 resistors and a capacitor. Here is what this should look like size wise (these are not the actual component values and are not wired - I just picked some from the junk box with the same size to arrange for a quick shot).
View attachment 1646448
i have been dying for years! for someone to do a 555 circuit!
 

thd9791

Master Member
RPF PREMIUM MEMBER
I promised I would deliver - for those not educated in electronics, here are the innards, sectioned, in a similar Casio calculator of that era.

1) I don’t think they revealed any of the chip
CE22934B-4573-4CE0-ACEF-3723B61FD181.jpeg

2) there are codes on the back, I never knew that
8856A8A9-0D94-48E7-89AB-9BDA5B5224AB.jpeg
 

Dann

Master Member
RPF PREMIUM MEMBER
I looked into a 555 timer circuit for a long time, years ago, when I first wired up the first blinking LED circuits. I went so far as to join an electronics forum, and ask for help there.

I’m pretty sure I was told that blinkers were available back then, and therefore there was no real need to go the 555 timer route. I could be recalling wrong, but I don’t think so.

I worked hard on that circuit, though, and I got pretty far, but I don’t think I took it all the way. Honestly, it’s been a number of years, and I just can’t remember. I’ll see if I can find that board that I wired up, but I think I ended up using some of the parts for another project.

Anyway, I finally got a nicer dental matrix part, and converted my last little atomizer into a tool. I promise I’m not making any more of these things, this is all I bought, and I ain’t buying no more, dagummit!
3A9C8E34-880A-4D0C-A4E7-8F89504FB664.jpeg
68119E93-52D1-4F8A-BEEE-456CAF276F94.jpeg
95A279CE-2E5E-498C-B1FE-AE035D782BB4.jpeg
3EA13F23-3B88-421E-9DE8-0685E4AFE36D.jpeg
E6F17405-1DD1-4D0B-800A-ADC0D5123707.jpeg
9776C784-780E-4820-AF44-DFC014924D69.jpeg
7D2B55D4-7FE9-47C3-8431-F1442777B8F2.jpeg
 

woodywaverider

Sr Member
Anyway, I finally got a nicer dental matrix part, and converted my last little atomizer into a tool. I promise I’m not making any more of these things, this is all I bought, and I ain’t buying no more, dagummit!
[
Very nice….are you sure….really sure…..that you don’t want a big square tool box full of them, slung round your neck, just like Wilfurd Brimley?
 

Halliwax

Legendary Member
RPF PREMIUM MEMBER
I looked into a 555 timer circuit for a long time, years ago, when I first wired up the first blinking LED circuits. I went so far as to join an electronics forum, and ask for help there.

I’m pretty sure I was told that blinkers were available back then, and therefore there was no real need to go the 555 timer route. I could be recalling wrong, but I don’t think so.

I worked hard on that circuit, though, and I got pretty far, but I don’t think I took it all the way. Honestly, it’s been a number of years, and I just can’t remember. I’ll see if I can find that board that I wired up, but I think I ended up using some of the parts for another project.

Anyway, I finally got a nicer dental matrix part, and converted my last little atomizer into a tool. I promise I’m not making any more of these things, this is all I bought, and I ain’t buying no more, dagummit!
View attachment 1646490 View attachment 1646491 View attachment 1646492 View attachment 1646493 View attachment 1646494 View attachment 1646495 View attachment 1646496

I seriously like the first two from the left, looks great with that little bolt holding them together
 

v312

Sr Member
I found some 555s, here's my idea in practice (I'm messing with it to make it work with the original capacitor from the calculator just for fun):
1670711512256.png
1670711634336.png


Touching the calculator keyboard contact works, but I've noticed that because the tool tip is kind of sharp, sometimes it slides a little and loses contact with one of the traces - making the red to just blink briefly and then the green one lights up again. Of course, if you do it carefully it works as intended. But having a momentary button under some of those pcb pieces would definitely be more reliable for Mark to hit it in the dark (I guess unlike me, if you use the force you don't really need light to be able to do all the soldering and assembling when building your saber, so it is perfectly normal to do it in a dark cave somewhere in the desert).

As for my own build I want to to make a circuit that would run just on a single cell or powered by the main battery of the FX build (So around 3V) the old 555 won't work , so I was thinking of a transistor based one. The more modern TLC555s should be able to do it , but if they were not available back then it kind of defeats the purpose. However I found that around 1975 another IC was made specially for the purpose of blinking leds and was quite popular also in the 80s and later (although it is now discontinued). It's called LM3909 and still can be found for around $10. Looks like the best option as it is period correct, looks very easy to use and will work even with a 1.5v battery. Just ordered one and will continue my experiment when it arrives.

This was my final version with the 555 if someone is interested to give it a try (adjusted to blink with a rate close to the one seen in the deleted scene while using the blue capacitor from the calculator):
1670738923109.png

(and it turns out it works just fine when powered with the calculator batteries)

1670778370024.png
 
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Dann

Master Member
RPF PREMIUM MEMBER
That’s cool, nice job. Excited to see what you do with the LM3909!

I made a quick and dirty little tool stand for Luke’s atomizer tool and these two other things I liked the look of. One’s an old pin vise made in Germany and the other is some kind of weird probe looking thing. When I modeled it I left a space for a bar graph LED. I thought it might look cool to make it seem like a charger base or something like that.

BAB783C6-971A-4585-AE24-E4A373CA88DC.jpeg
 

Halliwax

Legendary Member
RPF PREMIUM MEMBER
I found some 555s, here's my idea in practice (I'm messing with it to make it work with the original capacitor from the calculator just for fun):
View attachment 1646666 View attachment 1646667

Touching the calculator keyboard contact works, but I've noticed that because the tool tip is kind of sharp, sometimes it slides a little and loses contact with one of the traces - making the red to just blink briefly and then the green one lights up again. Of course, if you do it carefully it works as intended. But having a momentary button under some of those pcb pieces would definitely be more reliable for Mark to hit it in the dark (I guess unlike me, if you use the force you don't really need light to be able to do all the soldering and assembling when building your saber, so it is perfectly normal to do it in a dark cave somewhere in the desert).

As for my own build I want to to make a circuit that would run just on a single cell or powered by the main battery of the FX build (So around 3V) the old 555 won't work , so I was thinking of a transistor based one. The more modern TLC555s should be able to do it , but if they were not available back then it kind of defeats the purpose. However I found that around 1975 another IC was made specially for the purpose of blinking leds and was quite popular also in the 80s and later (although it is now discontinued). It's called LM3909 and still can be found for around $10. Looks like the best option as it is period correct, looks very easy to use and will work even with a 1.5v battery. Just ordered one and will continue my experiment when it arrives.

This was my final version with the 555 if someone is interested to give it a try (adjusted to blink with a rate close to the one seen in the deleted scene while using the blue capacitor from the calculator):
View attachment 1646771
This is wild!
 

Halliwax

Legendary Member
RPF PREMIUM MEMBER
That’s cool, nice job. Excited to see what you do with the LM3909!

I made a quick and dirty little tool stand for Luke’s atomizer tool and these two other things I liked the look of. One’s an old pin vise made in Germany and the other is some kind of weird probe looking thing. When I modeled it I left a space for a bar graph LED. I thought it might look cool to make it seem like a charger base or something like that.

View attachment 1646760
Genius idea!
 

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