开云体育

A number of years ago at the first Maker Fair in the SF Bay Area, San
Mateo, a gentleman brought a totally mechanical DA (a Babbage machine)
style made with "Mechano" parts it was huge about 10' by 15' it was
fascinating to watch it work with all the shaft's, gear's, cam's, and
sliding parts. The input was done mechanically and it did the output to a 8
bit dot matrix printer. He came to the first two or three Maker Fairs and
then we never saw it again.

Jim O

A number of years ago at the first Maker Fair in the SF Bay Area, San
Mateo, a gentleman brought a totally mechanical DA (a Babbage machine)
style made with "Mechano" parts it was huge about 10' by 15' it was
fascinating to watch it work with all the shaft's, gear's, cam's, and
sliding parts. The input was done mechanically and it did the output to a 8
bit dot matrix printer. He came to the first two or three Maker Fairs and
then we never saw it again.

Jim O

Chris,

There is a TR-20 on eBay - for USD $16,800!


<>


and an EAI 180 for even more:


<>

Where are you located?

A friend of mine has one but wants to keep it. He uses it - after doing a
lot of repair work on it (power supply, many of the op amps). Besides doing
some analog computer work, he also uses it as a music synthesizer. He
thinks that besides the “young folks” who grew up during the
microprocessor-based computers and have an interest in early computing
stuff (and money to buy it - you probably heard about the Apple I that sold
for an astronomical price) there are those who have gained an interest in
analog music synthesizers and are partly responsible for driving up the
price on analog computers.

Steve H.


On Fri, Mar 8, 2024 at 12:43 Chris Wilkson via groups.io <cwilkson=
[email protected]> wrote:

I just missed out on a fully loaded EAI Pace TR-20 a few years ago. I'm
happy/sad about that. They aren't light and they aren't small!
I hesistated on shipping cross country. At the time they popped up fairly
regularly so I was hoping to see one within driving distance. I'm still
waiting....

On a happier note, I built a dedicated analog computer to implement a 1-
or 2-player Vector Pong game with score and sound. It drops into a stock
Asteroids Deluxe (cabaret style) arcade machine and makes use of the built
in power supply and audio amp/speaker and that glorious X-Y monitor. It's
a big hit when I take it to public arcade shows. I had obsessed over
Pong's unfortunately square ball ever since I was a small child. That itch
has been eliminated. Vector Pong draws a true circle! :)

I remember them being advertised in so many techie magazines 50+ years ago. We called them "math grenades". I now have one, they are a work of art. The massive desktop calculators by Marchant, Monroe, Friden, and Burroughs are simply amazing as well.

Bruce Gentry, KA2IVY

On 3/7/24 10:56, garp66 wrote:

Another marvel analog mechanical calculator , of more modern vintage
is the " Curta " , popular in the 1950's to 1970's, but then eclipsed by the pocket calculator.

I finally go around to trying the XY display. It works quite well. As for the stretching characters, I don't see any of that; however, I'm waiting to get the replacement IC for the vertical board to see how much it still stretches with that. I should get that Monday and can do further testing once I get that installed.

Thanks,
Barry - N4BUQ

Another trick you can pull is to take the second scope, put it in XY
mode, and look at the outputs of the character generator, I'd initially
suggest the connectors to the V and H boards.? Should get the whole
vertical/horizontal amplifier question out of the way.

Harvey


On 3/2/2024 4:51 PM, Albert Otten wrote:

Hi Barry,

With the same setup you can add a second input (plugin or channel) in the
monitoring scope and display there the amplified signals present further on at
the vertical amplifier board. Triggering as before (R4470) should remain
unaffected when you change 7704A vertical position up/down. I would start with
the deflection plates. With DC coupled input the observed actual character
wave forms fragments will remain at the same vertical position while the
normal trace moves up/down when you change the vertical position in the 7704A.
Again you may see or not see an effect of that on the character waveform
fragments.

Albert

Another trick you can pull is to take the second scope, put it in XY
mode, and look at the outputs of the character generator, I'd initially
suggest the connectors to the V and H boards.? Should get the whole
vertical/horizontal amplifier question out of the way.

Harvey


On 3/2/2024 4:51 PM, Albert Otten wrote:

Hi Barry,

With the same setup you can add a second input (plugin or channel) in the
monitoring scope and display there the amplified signals present further on at
the vertical amplifier board. Triggering as before (R4470) should remain
unaffected when you change 7704A vertical position up/down. I would start with
the deflection plates. With DC coupled input the observed actual character
wave forms fragments will remain at the same vertical position while the
normal trace moves up/down when you change the vertical position in the 7704A.
Again you may see or not see an effect of that on the character waveform
fragments.

Albert

On Mar 6, 2024, at 4:21?AM, Christian F1GWR <f1gwr.groups@...> wrote:

?It took me some time to find out, as the service manual does not explicit what the "drawer" is. It appears this is the lower part of the tracer, under the display and upper front panel. It's a slider assembly including Lower Key panel, Bubble memory, component fixtures holder, collector supply switch. Explanation only appears in 370B Service Manual on page 4-15. You must remove two lower lateral brackets (with adjustable potentiometers markings) held each by 8 screws (four flat-head and four round-head. And then push forward the said drawer by its rear corners.
HTH.