What would YOU expect these circuits to do? (CES Ed-Lab 700)

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diophantine
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What would YOU expect these circuits to do? (CES Ed-Lab 700)

Post by diophantine » Fri May 24, 2019 4:59 pm

I'm starting to repair/redo/refactor a couple of CES Ed-Lab 700 systems. These were educational units (the newer-looking one is dated 1980) with a bunch of logic chips connected to banana jacks, plus some other goodies.

Well, here's some of those "other goodies". If you saw these, what would YOU expect them to do? Some may seem obvious, others not. And then some of the obvious ones will have additional inputs or outputs that might throw you for a loop (particularly the Schmitt Trigger and One-Shot... I have no clue what "R" should be on either).

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The reason I'm asking is because some of the other circuits aren't exactly what you'd expect and/or desire... And unfortunately we haven't been able to find a manual to see what they were supposed to do.

And yeah, there's really no rhyme or reason to the banana colors elsewhere, so don't expect that to help you! :sadbanana:

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Post by Grumble » Fri May 24, 2019 5:39 pm

I think R stands for Retrigger

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Post by diophantine » Fri May 24, 2019 5:55 pm

Grumble wrote:I think R stands for Retrigger
In the One-Shot?

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Post by UltraViolet » Fri May 24, 2019 8:19 pm

diophantine wrote:
Grumble wrote:I think R stands for Retrigger
In the One-Shot?
Could also be Reset. Wheres a 1974 National Instruments TTL Databook when you need one.

The bottom one appears to be CMOS unbuffered inverters like 4069UB.

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Post by UltraViolet » Fri May 24, 2019 8:21 pm

Maybe the Q and R on the Schmitt trigger are the two opposite outputs of a flip-flop?

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Post by ndkent » Fri May 24, 2019 8:26 pm

I have two ED Lab books for the 700, think I paid pretty much a pop. Can't get to them right now. You should be able to turn the panel and look up the chip. Most of the circuits are one logic chip. Then again looking at the blurry inside pic below, the area you are looking at contains circuitry. I'll follow up when I can get to the books

http://illudium.blogspot.com/2007/05/ce ... s-lab.html

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Post by diophantine » Sat May 25, 2019 10:15 am

ndkent wrote:Then again looking at the blurry inside pic below, the area you are looking at contains circuitry. I'll follow up when I can get to the books.
Yes, it is all discrete circuitry in this section, and a lot of it doesn't exactly correspond to the panel. (For starters, the "Comparator Op-Amp" uses no op-amp!)

If you ever find those books, that would be wonderful!!

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Post by ndkent » Sun Jun 23, 2019 11:02 pm

ImageImage[/img]

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Post by ndkent » Sun Jun 23, 2019 11:07 pm

T1, T2, T3 Solid State are just NPN transistors

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Post by diophantine » Mon Jun 24, 2019 10:59 am

Awesome, thanks so much ndkent!

I would never have guessed that the 'R' was for 'resistor' on those two circuits, and good to know how the follower hold is supposed to work. (I did determine that connecting 'R' to +V on the one-shot seemed to invert it, but it still seemed odd.)

I knew that the threshold logic was just those resistors, and expected the manual to have some fancy description of it with such fancy naming, haha. And good to know there's nothing fancy about the solid states - yeah, they're just NPNs with I think 1 extra resistor on each.

Any chance you could take a pic of the comparator and d-to-a descriptions? I know how they work but I'm curious if the manual has any interesting info...

Thanks again!

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Post by ndkent » Mon Jun 24, 2019 9:27 pm

Image

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Re: What would YOU expect these circuits to do? (CES Ed-Lab 700)

Post by ndkent » Sat Jun 27, 2020 11:17 am

There is more to this, just seeing if anyone is interested.
Sadly it aims to use a 900 series and two 700 series all at the same time
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Re: What would YOU expect these circuits to do? (CES Ed-Lab 700)

Post by EATyourGUITAR » Mon Jun 29, 2020 9:01 am

post a picture from inside, I want to see if it is worse than the pasco educational stuff from the 80's. there was a point to point power supply and some of the first opamps.
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Re: What would YOU expect these circuits to do? (CES Ed-Lab 700)

Post by KSS » Mon Jun 29, 2020 9:43 am

ndkent wrote:
Sat Jun 27, 2020 11:17 am
There is more to this, just seeing if anyone is interested.
Yes, enjoying the pages you're posting. Wouldn't mind reading the whole of what you've got for these units, TBH.

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Re: What would YOU expect these circuits to do? (CES Ed-Lab 700)

Post by ndkent » Mon Jun 29, 2020 3:48 pm

EATyourGUITAR wrote:
Mon Jun 29, 2020 9:01 am
post a picture from inside, I want to see if it is worse than the pasco educational stuff from the 80's. there was a point to point power supply and some of the first opamps.
my blog has inside pictures of a 700 and a 702 http://illudium.blogspot.com/

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Re: What would YOU expect these circuits to do? (CES Ed-Lab 700)

Post by KSS » Mon Jun 29, 2020 7:46 pm

Thanks! Love the Binson and the VDFG. And the Comdyna. And the plug-in cards. And the..
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