gigantic pc board

Got the first boards for my test set...

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I sure hope it works.

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John Larkin         Highland Technology, Inc 
picosecond timing   precision measurement  
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John Larkin
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"Gigantic"?

Reply to
Cursitor Doom

looks to be about as big as you can fit on a regular panel

-Lasse

Reply to
Lasse Langwadt Christensen

What the heck are the units on the non-inch side of that ruler?

Scaled feet or something?

--sp

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Spehro Pefhany 
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Reply to
Spehro Pefhany

5 thingies to the inch. I guess it's some sort of architectural ruler.
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John Larkin         Highland Technology, Inc 

lunatic fringe electronics
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Reply to
John Larkin

Scale, not ruler!

Reply to
Cydrome Leader

Gigantic price. They get expensive for ones that large.

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Rick
Reply to
rickman

On Thu, 17 Mar 2016 02:07:20 -0400, rickman Gave us:

You should have doubled up on all those horizontal rail vias.

Is that your multi-ARM board?

Oh wait. Those are all relays.

Hahaha. Sure spread them out a bit much. The whole board looks a bit sparsely populated.

Reply to
DecadentLinuxUserNumeroUno

50 parts to the inch.

Cheers

Reply to
Martin Riddle

Don't be a fathead. Nobody likes a fathead.

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John Larkin         Highland Technology, Inc 

lunatic fringe electronics
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Reply to
John Larkin

Actually five.

That '50' scale was useful when doing 2:1 taped PCB artwork. Long ago.

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John Larkin         Highland Technology, Inc 

lunatic fringe electronics
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John Larkin

Which ones? It's a 6-layer board with solid ground plane and one layer of power pours. It's heavy.

No, it's part of a test set. There is one LPC3250 that talks Ethernet or USB and mostly drives the 272 relays. The relay drive is one gigantic shift register made of 34 TPIC6595s.

There are a lot of traces, including some fat busses. Each front-panel connector pin can be relay switched to one of five internal busses, which can in turn be switched to all sorts of test equipment connected at the back. It was designed to fit into a relay rack and the depth was constrained only by our pick-and-place machine.

It's a 6 layer board. A dozen boards cost us $380 each. Each test rack will have two of these and a bunch of test equipment and will cost $20K or so. The most expensive thing will be the Agilent B2900A SMU which costs $5K or something like that. It's worth it.

Given that it's pretty much all relays, it was fairly hard to design. But the dial telephone system was once all relays too.

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John Larkin         Highland Technology, Inc 

lunatic fringe electronics
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Reply to
John Larkin

Not sure what a fathead is. Is it another completely wrong term?

Reply to
Cydrome Leader

It's anyone who presumes to correct my English.

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John Larkin         Highland Technology, Inc 

lunatic fringe electronics
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Reply to
John Larkin

Ahem... Keysight. (c;

Reply to
DaveC

No, HP!

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John Larkin         Highland Technology, Inc 
picosecond timing   precision measurement  
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Reply to
John Larkin

Ha! Retro-naming.

I wonder what name is planned to replace Keysight? I?m sure they have it in-hand...

Reply to
DaveC

On Thu, 17 Mar 2016 08:58:23 -0700, John Larkin Gave us:

But the vias are tiny. And that was a failed board, likely due to a via connection. The most common failure point in a multi-layer board.

So on those linear rails with all that space, I would have used bigger vias and two in a row in a lot of the layer interconnects, etc.

You could have put your little power supply on a perpendicular daughter card too to better manage the heat they generate.

Reply to
DecadentLinuxUserNumeroUno

On Thu, 17 Mar 2016 10:05:24 -0700, DaveC Gave us:

That's some pretty keyed sight you got there to notice that.

Reply to
DecadentLinuxUserNumeroUno

15 by 15 inches?

That was the standard size of Data General Nova and Eclipse boards some 40 years ago.

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-TV
Reply to
Tauno Voipio

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