The Beast in a box

Looks very nice.

Are the PCB hole pads around the back of the banana plug sockets grounded? Might be a slight chance of short circuiting the post part or bare wire strand to the PCB.

It is an impressive looking box however, I think I would wait for the neighborhood nitwit, SlowMan, to voice his opinion.

If you're lucky he may upgrade your status from rank Amateur to something more respectful. Off the top of my head and knowing how his head basically works, I would say "Amateur" would be the highest level of honor you'll ever get from him..

You can always look at it this way, one day SlugMan maybe using some life saving electronics that could not come into existence without the aid of a design from your business.. I bet that would scare the hell out of him!

Jamie

That display board is a tad weird. I designed the big one but not the display board. I didn't want the display, so I told the people who did, that if they wanted it they could design it. But the clearance holes are connected to the wire pads, so a short there won't matter.

The bananas are the contacts of a SPDT power relay. That lets us use the contacts to, say, power cycle the DUT many times overnight, or switch a big load resistor on and off, or something.

We're building a dozen of these boxes, and people are writing zillions of lines of Python. This is our universal test set, that can test most of the products that we make. It replaces all sorts of ugly hacky old fixtures that use a lot of DOS software.

I wanted to make nice polycarb overlays for the front panel, but nobody has time to do the artwork. Might still, some day.

The green electrolytic cap, upper right, had to be hacked, the only kluge on the board. The 24 volt wall-wart supply, driving the LTM8023 switchers on the board, oscillated because of the negative input impedance of the switchers. We could have used a different 24v supply, but the cap kills the oscillation.

Well, designing a board full of relays probably won't win me many awards.

Sounds like an "All in the Family" episode. Slowman does have a lot in common with Archie.

Den fredag den 21. oktober 2016 kl. 18.38.12 UTC+2 skrev krw:

True, however, I do feel it's past slugman's caliber.

Jamie

Ah, but putting all those relays into a RETMA rack connects you spiritually to four previous generations of electrical engineers...

When I was a kid we visited a small telephone exchange, back in the days when kids were welcomed almost anywhere. It was all big Strowger stepping relays, and it sounded like a war zone. We asked if we could have a chunk of zillion-pair cable in the trash can near the exit, but the guy said no, it had to be recycled, then he left us alone. So naturally we stole some.

We could go to the airport and hang out in the control tower, too. Didn't steal anything there.

Slotted screws? You're not German are you?

No upgrade until he becomes a sickening ultraliberal Hillary/Israel supporter.

Not sure if I forgot or never knew, What is tha5 thing supposed to do ?

Me? German and Irish and a few other things.

Two years ago I stumbled upon technicians replacing the underground phone cables outside my mother's house. It was enamelled wire, twisted into pairs separated by waxed paper, with the cable encased in lead sheath. I asked, and they chopped off a foot for me :)

I /really/ wish I had sawn 1cm off a cable lying around in my first job. It was TAT7 cable, the last trans-atlantic coax comms cable. 61.8ohms, IIRC, and it couldn't be any other value.

I'm still using single-core hookup wire that came from London Airport ATC Centre in the 1970s :)

That's back when "America" was "great". They used to have take your kid to work with you days. Now there is so much possibility of a lawsuit there is no way a company in their right mind would allow it. No matter what Trump s ays, there is no going back. Sorry.

Den fredag den 21. oktober 2016 kl. 23.31.26 UTC+2 skrev snipped-for-privacy@gmail.com:

afaict basically a enhanced purpose build version of this:

I posted about it a while back, when I got the first PC board.

We have a zillion products that have all sorts of i/o connectors. This is a relay matrix that connects any DUT connector pins (the connectors on the front) to the test equipment connectors on the back. DVM, scope, counter, SMU. A computer runs Python and talks to everything, with a test program for each product.

There are fundamentally five internal busses, A B C D E, that DUT pins and test gear can be switched to.

It has a little internal electronics too, some 4-wire test resistors, a low-offset X100 amplifier, a few odd things that various DUTs need.

Two of these will go into each test rack, with the test equipment. We'll build several racks. This can test DC or slow AC stuff, but not the nanosecond/picosecond products. The relays are good to a few GHz, but there's too much traces. Maybe we'll do a fast, simpler, impedanced matched version some day.

I could post the schematic if anyone is interested.

That's nice! Why not get out the whip and have your minions engrave that panel on the Tormach?

--sp