Reducing the item cost for printed-circuit boards.

[nomadradio]

Printed circuit boards used to be an expensive proposition to have custom-made. Automation and the internet have reduced the cost a lot the last 20 years, but the per-order setup fee is still a bit steep. There's a low-tech way to reduce the item price.

Combine multiple boards in one order, and shear them apart. This spreads the per-order setup fee across three or four products, instead of just one.

Here's one expample.

The big one is the latest low-voltage pcb for the Pride DX300. I use a large power resistor on this board, and finding a batch of 50 or 100 of these cheap is a hit-and-miss proposition. As a result, the board gets designed to match the mounting requirements of each batch of power resistors. Sounds a bit like letting the tail wag the dog, but first I buy the resistors and then the board gets configured to match them.

Buying 50-Watt resistors at the full catalog price is never my first choice. Especially when I buy 50 or 100 at a time.

The lower-left of the three small boards is an adapter. It will put a 4-pin mike socket in place of the 5-pin socket on your Cobra 142, 2000, Uniden Madison, Washington and similar 40-channel SSB radios made by Uniden. It keeps the two ground circuits separate and eliminates the 'squeal' issues you get doing this the simple way. It also allows the use of roger-beep/5-tone beep/Bump-Bump boards that don't have a relay to mute the speaker. This one is version 6, and has two relays. One to key the transmit side, and one to delay turning the speaker back on when you unkey. This eliminates the unkey "POP" you get from the speaker when using a single relay.

The other two are the full-swing carrier control for Browning and Tram tube-type radios.

Now the real work begins. Getting hundreds of boards built.

73

 

[711]

Where's your website? I want a few of those mic boards built or not.

 

[Tallman]

That's pretty sharp! Do you use Gerber files?

 

[nomadradio]

Gerber files?

No, I'm still not quite that sophisticated. No doubt the time is long overdue that I set up CAD to produce standard output files. I use Expresspcb.com. Their CAD is free, but produces a proprietary output file you upload to their server when placing the order. Nobody else accepts their file format that I know. Yes, they are more expensive than the China pcb fabs. But their quality is high, service and support are VERY reliable and I have 18 years' experience using their CAD program. Yeah, I should upgrade my software/skills and have boards made offshore.

Soon.

We always say that.

Website?

Waste of time, for now. It's 12 or 13 years out of date. Should update it.

Soon.

We always say that.

The mike-adapter bare board isn't much good without the documentation to populate it and get it wired up. My experience with DIY kits so far is that the labor to pull the parts, pack the kits, check them for accuracy and print instructions is nearly the same or more labor as just building the thing and testing it. That's why I quit selling the Pride HV board as a kit. Cost me more, paid me less. Like whacking the back of your hand with a hammer. Feels so good to stop.

The 4-pin adapter board has mostly gotten used here to meet customer demand, or sold to folks with the technical chops to get them installed without 'support'. A product that takes twice the labor to 'support' it as it did to build will suck your bank account dry. Doesn't appeal to me.

Then again, selling a tested item simplifies that support issue. If it won't work, it's because you wired it up wrong. Hook it up right and your problem will go away.

That's the kind of support I can afford to provide.

The point of attempting to build a batch of 50 is the hope that a few customers will decide it's useful enough to buy five, ten or more at a time. Since the cost of making a sale is pretty much the same to sell one as to sell ten, I can make the price more reasonable that way. Piling the cost of a sale transaction onto a single unit will probably make the price for "just one" look too high to be attractive.

People love to whine about the minimum-order policy at everyone's favorite candy store "Arf Parts". They would like to order a 79-cent capacitor and a two-dollar RF choke. The minimum-order amount provides an insight into the overhead cost of making a sale. If Merrit wants a 20-buck minimum, it sounds as if his overhead cost per transaction must be close to that.

And I can't do business much cheaper than he can.

Maybe I should revisit the cost calculation to:

-> Write detailed and correct instructions to install it into a dozen or more kinds of radio.

-> Write detailed and correct instructions to stuff the board and get the right parts soldered in the right spot.

-> Pull 800 parts from stock and "kit" them with the right 16 pieces to build one board.

-> Check each kit for missing and wrong parts.

-> Print a copy of the instructions for a dozen or more radios.

-> Pack them up to ship.

Fifty times.

My take on the subject of "support" is that the more steps the end user must take, the more opportunities for error you create. A bare board sold with parts will generate many, many more times the "support" requests as an assembled, tested gadget.

A product that you hook up to five wires, and solder the sixth wire up for power and bolt into place leaves a lot less to chance.

Besides, it was designed to fit in place of a smaller board the factory put onto the original 5-pin socket. Getting it all crammed in that space makes it tricky to assemble. Parts are crowded.

If you wish to design a pc board to sell a successful kit, be sure to leave plenty of elbow room between the parts. Makes it easier to assemble, and harder to screw up.

Not the way this one is laid out.

The crowding is necessary.

And no, I didn't write assembly instructions for the hired help here. I just build one and he copies it.

Really well.

A lot more efficient for me.

And the guys I have sold them to so far each have a radio with one of these already in it. Simple to copy if you have a "crib" to work with.

But yeah, I should invest the money into making that toy a marketable product.

Soon.

I always say that.

73

 

[kopcicle]

you need a round to it

 

[loosecannon]

Nomad's round tuit is made of unobtanium.
LC