EEVblog #1130 - Mailbag Monday

More Mailbag Monday

SPOILERS:
A-TEK AT-601 PC ISA Bus Design Breadboarding Tool
Gigatron TTL computer update
VintageTek museum XY demo board
1970's Casio CQ-1 Calculator
Zofz PCB Gerber Viewer

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[DVSProductions]

"press [A] to select program"
Dave: *presses Enter*

[nullunit]

You should try and repair that CQ-1. Would be a fun video to watch.

[gblargg]

11:59 In the background Dave's scope burns a hole in the phosphor...

[darthvader]

Boggles the mind a bit to think about why you'd need a stopwatch and lap counter on the bedside table...

[videolabguy]

5:00 - That's the circuit to turn a one channel o'scope into a four channel logic scope - note: not analyzer. Your choice of chop or alternate between the four inputs. 555 timer, the monkey that turns the handle. A 7474 as the two bit counter and the 74153 four to 1 decoder as the channel distributor. Easy peasy!
(Yes! I have designed boards for the EISA buss. Painful! Even at only 12MHz, you had major timing problems.)
The Tektronix gizmo now includes contacts for two pots so one can play a rezounding game of tv tennis! Note: one or both of your probes were not calibrated. I get the picture of the wizard with a perfect square frame.

[Mattx]

"press [A] to select program" in huge letters right on the screen... Dave mashing the enter yelling at the computer..

[SoftBreadSoft]

"Not a real electronics product, it's got a spring in it." haha

[acousticpsychosis]

I watch a few other channels that do mailbag type videos now and then, but I gotta say, you do it the best...actually take time to look at and talk about what you got. Good stuff!

[edgeeffect]

That breadboard thingamy is marvelous. Back in those days, I could do simple stuff using the serial port's handshaking lines as GPIO. But there was no way someone on my budget could get their hands on the ISA bus... saying that, it was probably way way way off my budget to have one of those.

[emmettturner]

4:47 - Dave laughs at them using “hot snot” on the screws.
5:16 - A loose screw he did not remove falls right out.

Hmmm...

[Audio_Simon]

Bed side calculator, but of course. That's where I do my multiplying.

[hi-friaudioman]

Thumbs up for the CQ-1 70's calculator/stopwatch/alarm clock. I would love to see that work again!

[chromabotia]

Great to see Mailbag Monday again! Tightly edited too!

[RobTaylor-HiTech]

The Casio took me back! Much love! Had one of those as a kid!

[dhpbear]

11:50 - I'm curious about that curve in the lower-left of the 'scope. It appears that the signals are ac-coupled at the board?

UPDATE: The compensation on the probe attached to 'X' needs to be tweaked.

[briandecker]

My wife just returned from a business trip to Sydney bearing TimTam biscuits - they are amazing!!

[Ziferten]

I take personal offense to a main channel video without "Hoy!" -- A phrase which I believe is a salutation in the Australian language.

[frigzy]

The BNC part of the prototyping board will probably output 4 digital levels from the connector bellow in sequence like 0-1-2-3 issuing a sync pulse at the beginning of each "frame". Sort of converting an oscilloscope into a 4-input logic analyzer.

[tzisorey]

Anyone else disappointed that the Gigatron never has an entry in the menu for "Global Thermonuclear War"?

[FindLiberty]

That Casio could also calculate time entries, e.g. 02:01:00 + 16:00:59