Large PCB source for dead bug homebrewing?

eBay.

-- jm

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Hello Tim,

See if there is a PCB manufacturer within resonable driving distance and ask for scraps. That's how I got a huge stash decades ago. Single and double sided, the good stuff (FR4). But it has to be picked up, in my case they wouldn't have gone through the trouble of packaging and mailing it. Basically it had to be no more effort on their part than a walk to the dumpster would have been.

Mine weren't tinned though. Also, I am not sure if constantly touching a pre-tinned board during experiments would be too healthy.

Regards, Joerg

Hello Tim,

Just one more thought: I use "living-bug" arrangements almost exclusively. Every once in a while I cut up some strips so they fit the most popular "underbellies" of chips. Then I glue the strips onto the large panel and the chips on top of the strips in a rider's fashion. Ground connection can be achieved by slightly bending down a pin, the rest gets wired up Sauerkraut style like usual. When stray capacitance is critical I take washed wood strips instead of copper clad. Makes for a really nice excuse to eat another Haagen Dasz.

This avoids having to think in reverse pinout and it often looks nicer, too. Plus you can still see the "CD4007" on the chip.

Regards, Joerg

Or you can just bend all but the ground pins outward from the base of the chip (e.g.,

Sometimes I'll use a drop of cynaoacrylate adhesive to hold the chip into place if there are few or no grounded pins, but it's rarely necessary.

This also works for SOICs and even TSSOPs, as long as you don't bend the pins more than once.

-- jm

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Hello John,

But then I won't have an excuse to eat another Haagen Dasz bar :-(

Regards, Joerg

From: "Tim Shoppa" on Tues,May 3 2005 10:22 am

the

Ebay might be good as someone else suggested. The best bet for low CO$T material is to sweet-talk a PCB maker for left- overs...if one is in your neighborhood. I've gotten fairly good prices from

Cleaning OLD PCB stock the "green" way -

Sprinkle any kind of table salt on the PCB stock, then take half a lemon and rub it on the salt. Most of the blackened oxide will disappear!

I tried that late last year on some 4" x 8" double-sided phenolic substrate PCB stock after seeing all those "green" site remarks that I didn't really believe. It WORKS! :-) Those pieces had been sitting in the back of the workshop for about 35 years.

I did "cheat" a bit. Have a year-round producing lemon tree and my wife had some coarse salt left over from a canning experiment. Zero cost trial...lemons at the markets can run 50 cents each. The residue can easily wash down the sink, don't need any gloves, nothing toxic. Result is easily solderable although for best appearance, some cleaning with a bleach-containing kitchen cleanser will make it shiny and spotless.

snipped-for-privacy@ieee.org

For what it is worth, as the others say Ebay is good. I picked up 5

and

Why is that? Lead? I thought that paint with lead in it was a lot worse.

the

for

nicer,

Back in the early '70s I got some prototype boards from a company that made aircraft receivers. They used four push-in pins, one for each lead of the four corners of the IC. Two of these are usually power and ground, pins 7 or 8 and 14 or 16. These four hold the chip up off the board, and the other pins are wired spaghetti style, which I presume is the same as your sauerkraut style.

Speaking of this.. Last Sunday at our monthly compouter club meeting someone donated a homemade S-100 system to the consignment table, but no one bought it, so it ended up on the freebies table later, probably then into the trash later. It had a chassis and box pop riveted together, and the S-100 bus was all wire wrapped. A lotta love and time went into building that way back in the late '70s.

the

the

the

capacitance

for

nicer,

the

What's the board in? A receiver? What's it do?

of

You don't need an excuse. We give you permission. ;-)

BTW, you can go to Michaels or other hobby/crafts store and buy a whole handful of ice scream sticks for a couple bucks. You don't have to wash 'em, then. :-P

Every year the Engineering Club has a model bridge building contest. They make them out of ice scream sticks. They support the ends of the bridge on some bricks and suspend a bucket from the middle. Then fill the bucket with sand until CRACK! the bridge crumples. Pretty neat!

You could come on over afterward and get some free slightly used ice scream sticks. :-)

Ditto. You got a better deal than I did. I got 5 sheets about 14x14, single sided, for 10 bucks.

-Bill

I've amazed a few people when we go out to eat lunch. I take a tarnished golden dollar and put it in the lemon from a drink, or catsup works just as well. Less than a minute later, it's nice and shiny again. The vinegar or citric acid reduces all that tarnish to invisible. Some say the carbonic acid in the fizz in cola will do it, too, but I haven't tried it. Check it out sometime when you're into impressing your friends.

Just make sure you don't get any of it in a cut on your finger. The lemon will add a whole 'nother meaning to rubbing salt in your wounds!!

It's a PLL that locks a Tek 492AP spectrum analyzer to an external 10 MHz GPS reference. The box contains an x100 prescaler, x10 prescaler, a phase/frequency detector made from two halves of a 74LS74, and a slow loop filter made from an LF356 opamp. There's also a relay that switches the correction signal in and out of the circuit based on whether the GPS reference is connected.

The 494 and 494A had the reflock assembly built in, but the 492A didn't. So I added it, along with a few other tweaks that bring it up to 494A- level functionality.

Lots of stuff in a very small box, without much room for component standoffs or other prototyping aids. I've built a ton of stuff that way, at frequencies up to and including 2 GHz. Wouldn't even consider any other assembly techniques for RF work at this point.

-- jm

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Hello Watson,

I believe yes, plus other additives.

Regards, Joerg

Hello Watson,

HD and Lowes have suitable hardwood strips, too. That is what I use when it is a client's breadboard.

But these still don't come with vanilla almond chocolate crunch. However, there is a trailer in front where they sell jumbo cajun links...

Regards, Joerg

Hello Watson,

Neat. Yes, sauerkraut style is similar to spaghetti style. No meat sauce though ;-)

Oh, wire wrap. Most older computers were that way in the 70's when I was at university. It caused a lot of grief but then I found out an upside. As a student you are always short of money, looking for an opportunity to make a buck. These old wire wrap graves still would have some life in them but not enough for the institutes to warrant the huge service contract expenses or $200/hour repairs. So they just sat there, dead. Then I offered to repair them provided I could do it my way. Brought the big solder iron and soldered the whole backplane which brought them back to life. They actually ran more reliably then ever, some told me. Often the pay wasn't money but a keg and pizza which was then immediately consumed by me and some staff on the lawn in front of the place.

Regards, Joerg

The guy actually sent the stuff from Canada and the shipping was fairly cheap too. If I remember it was around 10 bucks...It sure beat those little radio shack boards. _____________________

=============================== Printed circuit board scraps up to large pieces ,be it usually double sided , are always available at ham radio flea markets in the various european countries. I think I have stocked up for life ! From the larger bits you can make neat enclosures.

Frank GM0CSZ / KN6WH