EEVblog #1130 - Mailbag Monday

[EEVblog]

More Mailbag Monday



SPOILERS:
A-TEK AT-601 PC ISA Bus Design Breadboarding Tool
Gigatron TTL computer update
https://gigatron.io/
VintageTek museum XY demo board
https://www.ebay.com/str/vintagetek
1970's Casio CQ-1 Calculator
Zofz PCB Gerber Viewer
https://www.zofzpcb.com/

[maginnovision]

I was just messing with one of those tek boards and some other oscilloscope art stuff last night.

[Muttley Snickers]

8:30
Use [Arrows] to select
Press [A] to start program

"Do I have to read the instructions"

 

[EEVblog]

8:30
Use [Arrows] to select
Press [A] to start program
"Do I have to read the instructions"
 

They are the same instructions as for the original ROM that used the Nintendo controller thing, so I kinda just subconsciously ignored them assuming that the keyboard version worked more sensibly.

[marcelk]

The programmer* also didn't see that line for months.
https://github.com/kervinck/gigatron-rom/issues/38

*me

[drussell]

Great Mailbag episode... 

i would expect that the 244 on the ISA card was probably fried and replaced by a user rather than being mismatched from the factory.  I've certainly blown up my share of 244 and 245 chips.   

Does the CQ-1 power up at all?  It shouldn't be terribly difficult to diagnose basically what is wrong.   

[mrpackethead]

 Hey Dave, just noticed this particually on this video

The audio in your video is below the Youtube Reference level by 4.9db     Youtube does weird things with normalisaton and stuff, ( you can google this topic ).

You might want to run a loudness meter in your audio, before you push it up to Youtube, to get it up to about  -22 LUFS

[ggchab]

Nice video 
Another demo of the Tektronix logo board by w2aew:

[Brumby]

Tandy were selling their Radio Shack branded version of that Casio alarm/calculator back in the day.  I remember working in their store in Westfield Parramatta when they came in.  They were the ants pants.

[Lajon]

Still have my Casio CQ-1 (from 1977 in my case), it stopped working some years ago (the display and one or more switches I think). It's actually not strictly a "4 banger", it can compute with date and time (like number of days between dates). Ok, not super useful but everyone got to know their age in days.
/Lars

[Ferenc]

That's a knife!

[SeoulBigChris]

I built a circuit back in the day to display the polarization of an RF signal in real-time on an oscilloscope, similar to this Tek device but not quite so fancy. I only drew a polarization ellipse on-screen, and used the z-axis to make the trace look like a dashed line for counter-clockwise polarization (solid was clockwise). I’m surprised the Tek device doesn’t use the z-axis to “pick up the pen”, so to speak, while tracing out the sketch. Without z-axis modulation, it’s like drawing something on an etch-a-sketch.

[bitwelder]

It seems Dave missed one special feature of the Vintagetek XY demo board: play tennis on the CRO!

With no jumpers, the board alternates between the logo and the Wizard, a few seconds each. The images are displaced slightly periodically to reduce the possibility of screen burn-in. To draw only the Logo, connect the pad marked “L” to ground. To draw only the Wizard, connect the pad marked “W” to ground. To play tennis, connect two pots to +5 and ground, with wipers to the P1 and P2 pads and ground both W and L pads. The mode is determined at power-on. Thereafter, any changes to the W and L pads have no effect. The pots should be linear-taper and between 1K and 10K.