bread boarding taken a little too far

Looks like a ten bit A/D converter.

Hmm.... Quite normal. Have you ever seen a pdp7 computer's inside? Now that was a real maze of spaghetti wiring(around 1969).

Where can you get a vector board that big ?

hamilton

Gotta be >60 trimpots on there.

Best regards, Spehro Pefhany

I used to work with a power supply designer who surrounded all his breadboards with a cloud of white wires by the time he got them working. "Keeps the smoke in".

Must be analog, and have some problems as-is: a) go up one "add-on" board on the right and notice one IC half-way plugged in; b) go above the second "add-on" board on the right and see a BAER wire shaped like a lower-case "e"; that is the you-know-what worst browser that Monstor$tomper (or any other "programmer") made.

Check out the 18k resistor just to the right of P29. WTF?

On a sunny day (Wed, 7 Jul 2010 18:24:25 -0700 (PDT)) it happened " snipped-for-privacy@fonz.dk" wrote in :

At least somebody had patience... Wonder what the bottom side looks like...

Here one of mine: ftp://panteltje.com/pub/z80/graphics_card_top.jpg ftp://panteltje.com/pub/z80/graphics_card_bottom.jpg

schreef in bericht news: snipped-for-privacy@j8g2000yqd.googlegroups.com...

Breadboard? It's a creation, a work of art. You may get legel problems by publishing a copy of it :)

petrus bitbyter

the left board looks strange to me.

it doesn't appear to have copper traces except on the edges. Am I seeing this wrong? I can see drilled out spots where traces would have been cut, but I don't see the traces.

The right side except for being surface mounted makes more sense. The soldering is pretty need. Is there some 1980s technique to keep solder from flowing down the trace?

• Sorry; meant LEFT---------------^^^^^

You need to look rather carefully, enlarge by a factor of two and look here and there. The traces are BAERly visible due to the light angle being a bit different.

Did Ma Bell give you a thousand feet of 50-pair cable? Isn't there a lot of ringing and cross-talk, or is the clock rate low for a slow-scan system (FAX or weather)?

What did you use for the background? It seems better than a rug or towel.

On a sunny day (Thu, 08 Jul 2010 11:24:55 -0700) it happened Robert Baer wrote in :

Much better, my desk, 'formica'.

That's the shittiest wiring job I have ever seen in my life.

On a sunny day (Thu, 08 Jul 2010 11:10:47 -0700) it happened Robert Baer wrote in :

Yep, it is from an old phone cable IIRC.

It is an 18 MHz xtal, nothing slow scan about it, 80 characters at normal TV resolution 15625 Hz / 30 Hz. You needed a very good TV monitor for that, a TV set would not be able to display 80 characters. The CRT controller is the famous Motorola 6845

Actually below about 30 MHz, the TTL 'limit' so to speak, wiring like this works just fine. the capacitance between wires is very small. Most of the signals on the board are slower anyways, only the shift register that shifts out the pixels runs at full (pixel) clock. The big 64 pole DIN connector is actually compatible with the old 'Elector' (then Elektuur) bus. The processor board was a 4 MHz z80: ftp://panteltje.com/pub/s/z80_board.jpg I know it is out of focus, will have to make a new picture one of these days.

The wiring is on the backside with stripped flatcable. ftp://panteltje.com/pub/s/wiring1.jpg

The whole thing runs my own OS, a CP/M clone, written in asm.

I made many more cards, filled up 2 backplanes.

You might be confused by the 6-pin devices installed in 8-pin sockets; opto-fets probably.

Nobody said it still worked, but you might be surprised.

RL

I think it was hanging out along one side, half the pins out of socket.

The labels look old and faded?

Grant.