There is PCB and then there is PCB

[J M Fahey]

Hi ken moon, *thanks* for posting.
Just hope the trenchcoat and hat guys don't send you to Guantanamo on a one way ticket.
Love to see "the real deal" with my own eyes.
As usual, "real life" is much more solid and to the point than imagination.
What amazes me most is that these PCBs are so close to a normal, well made commercial/industrial product.
No gamma ray generators, plutonium bars or Moon rocks here.
Yes, I'm sure they were made with with the best, deeply tested (no random sampling here) and of course, must have cost more than a similar commercial product .... but they are not "something else" , if you know what I mean.
PS: don't want to know what they exactly are or do, just looking at them was enough.
Thanks again.

[teemuk]

What amazes me most is that these PCBs are so close to a normal, well made commercial/industrial product.

What I've gathered from the "black box" photos I've seen so far the PC boards used in them are pretty generic. You won't find any magic stuff from them. However, a great deal of thought has been spent on mechanical design: how to properly support the boards to withstand shock and flexing, how to make the most rigid, literally bomb-proof, chassis construction, etc. Also, it's wortwhile to note that when things go bad, the PC board is just a bunch of junk that can always be replaced. What they really want to protect is not the circuit board but the recording media (hard-drives, tapes, whatever they happen to use).

What's also worthwhile to realize with military and industry applications is that the most important thing in terms of fixing them is redundancy and spare parts. If things fails the first thing is not to start fixing things on component level; what you do instead is that you quickly throw in a spare part, such as a circuit board card module. You can't afford to spend several minutes or hours in fixing things when they've got to work immediately. Fixing things on component levels starts only when there's time for it.

So, analogically, you really don't need an amp that can withstand a nuclear blast in a fighter jet shocked by tremendous G-forces, or likewise an amp that is extremely easy to repair on component level. What you really need is a backup amp. When you're at a gig and the amp fails you can't pop up the hood and start soldering, but you can spend few minutes to patch on to that backup amp of yours. That's "military" style.

[Ken Moon]

So, analogically, you really don't need an amp that can withstand a nuclear blast in a fighter jet shocked by tremendous G-forces, or likewise an amp that is extremely easy to repair on component level. What you really need is a backup amp. When you're at a gig and the amp fails you can't pop up the hood and start soldering, but you can spend few minutes to patch on to that backup amp of yours. That's "military" style.

Well said.

When I went to see Joe Bonamassa recently, his Silver Jubilee bit the dust (funny that it was the Marshall and not one of the three boutique amps he was using), and his crew had a spare in place in about one minute - before the song ended.

That being said, I wouldn't trade one of my nice amps for two crappy ones

[Steve Conner]

Well, I once went to the Marshall Roadshow, and of all the amps they demonstrated, it was the handwired Hendrix plexi reissue that bit the dust. It died after a couple of good power chords. Period correct screen voltages maybe?

Thanks for posting the "black box" pics. I guess it's not secret, after all, it's the part they want you to find in an accident. The really secret stuff probably has explosives strapped to it, like the IFF units in World War 2, to make sure nobody ever finds it in an accident.

I know the JSTARS reconnaissance aircraft has an emergency routine that the crew can activate to wipe all of its numerous hard drives.

[RudeBoy]

<snip>The military have the same problem I do, they can't use through-hole boards because they can't get the latest gee-whiz computer chips in a 40-pin DIP.

While I wish it not to be true, I would not be surprised to find my Markbass LM2 uses ball grid arrays on some parts.

To the question of what the military uses, like other sorts of industries - it depends on what environmental qualification categories the equipment is to be certified. We had a unit in qual recently burn holes in the PCB when it failed during fluid testing where the fluid was de-icing fluid (one of several including hydraulic oil, insecticide and detergent). We got a waiver because our gear was not required to be installed in an aircraft wheel well.

As to commercial quality, i think it is safe to say that much less stringent requirements apply, though I think a beer or alcohol spray fluid test could have some merit.

[J M Fahey]

a beer or alcohol spray fluid test could have some merit.

That's nothing, in fact pure vodka will actually clean your gunk and then some.
Much worse are *sugared* drinks which caramelize and *glue* everything, once dry are excellent insulators (as in covering contact surfaces) and beyond relatively mild 100ºC toast and carbonize, becoming conductive.
Oh well, all bad traits under the same roof.

[Enzo]

Just thinking idly... once the plane crashes, does it matter what happpens to the circuit board? Doesn't it need to survive up to the crash, and then it's job is over? Th recording device sitting inside a rubber ball bounces to safety...

[Ken Moon]

Just thinking idly... once the plane crashes, does it matter what happpens to the circuit board? Doesn't it need to survive up to the crash, and then it's job is over? Th recording device sitting inside a rubber ball bounces to safety...

You're right, but these days, recording devices may be networked hard drives that could be physically located anywhere, and there may even be multiple levels of backup.

Military avionics are becoming very much like a home PC, as far as processors, interfaces and protocols at least, though they often communicate on different networks than the www. I recently worked on a garden-variety avionics box that had 4 separate ethernet cards in it, used to communicate in real time with other boxes in the aircraft.

PC operating systems such as Embedded Windows XP are showing up in more military boxes now too, along with the traditional real-time OSs like VxWorks. I don't think Windows is used in any flight safety critical systems though - I'd be worried that the "blue screen of death" could become a bit too literal

I guess I've dragged this thread pretty far off topic - sorry about that

[defaced]

PC operating systems such as Embedded Windows XP are showing up in more military boxes now too, along with the traditional real-time OSs like VxWorks. I don't think Windows is used in any flight safety critical systems though - I'd be worried that the "blue screen of death" could become a bit too literal

If Windows performance on the welding equipment I use daily is any indication of how it performs in other industrial tasks, then God help you all. Bill Gates didn't have welidng in mind when he designed windows, and I have a feeling military boxes weren't on a radar either.

[Steve Conner]

Well, the box I showed earlier runs Windows CE on one processor and TI's DSP/BIOS on the other. CE6 is pretty stable and lightweight compared to desktop Windows. Less features means less bugs. It's no real-time OS, but that's what we have a DSP in there for. Power budget for the whole box is 25W.

Likewise, XP Embedded is probably pretty stable and/or lightweight compared to Vista, 7, Mac OSX, Ubuntu etc, which I guess justifies the "Embedded" branding, that being the only difference between it and good old XP. But it's no real-time OS either, even less so than CE.

[diagrammatiks]

There are good PCB's and bad pcb's.

These are the best of the best.

My old RV100


Orange's boards on there chinese stuff is nowhere this good.

My THD Flexi50 Built like a tank. No more pcb then absolutely necessary.



Fuchs Train45 - Showing that there is a definite difference between "translating" a circuit to a board and "designing" a board



My Slo



Instances when the builder/designer no longer has time to build the circuit himself, I'd gladly take a well designed PCB.

However, for one offs and things I build I much prefer boardless handwire or preferably milspec ptp.

This gets close.



But this is better

[Tilman]

Hi,

a little late to jump in here but I would like to make a comment on the "made in..../China" discussion.
I think R.G. is right if he points out that economy and money rules the world. Lately it seems it is more the money, not the economy BUT :
If I buy something "made in Germany" (I come from Germany) I am quite sure that people working on the product do not have to live with other co workers in 12 men containers, do not fish for parts in acid liquid without gloves or breathing masks, that waste water and gas is treated before it is thrown out to the environment - just to name a view common things in the so great chinese manufacturing world.
Sure, there are parts inside the product that might have been manufactured under such questionable circumstances, but at least it is not 100% of the product.

It is not that I read about chinese production methods in german industry propaganda magazines. I was there. I have seen it.
Tilman

[teemuk]

My Slo

I have always wondered what great people see in Soldano boards. Single-sided, no solder mask, no silkscreen, often lacking plated through holes, very few supports to stop flexing, big components spacings and long track draws everywhere. C'mon? Seriously? Just Because it comes from a known boutique manufacturer doesn't instantly make it great.

The only somewhat good thing I can think up from them is that the copper side is moderately thick but that's about all. Maybe I just fail to see something obvious, though.

But this is better

Try accessing some of those components underneath a bunch of other components and wiring. Then they are connected to several other components from both ends so to remove and replace one you actually have to remove several and then assemble everything back together. ...And before that, dissassemble all the components and wiring that would be on your way of doing that. The guys repairing PCB amps like to make remarks about difficulties of having to dissassemble a lot of stuff but on that regard most of these rat's nests are an even greater nightmare. They may look great and hold up well but all in all their repair ain't such a breeze as commonly believed.

e.g. See the attached photo. Try replacing the circled components. How fast would you do it in this method on a PCB amp: Nip off the components from near vicinity of their "body", solder replacement ones to the old "legs" that you left there sticking right up from the board. I realize it's not recommended practice but it's still as rigid as generic point-to-point put together in about same way. No flipping of PC board or any other dissassembly required. You can't really do it that way with this kind of PTP amp because soldering on and off the components would degrade all those other solder joints in the process or simply remove a lot of the other components at the same time you aimed to remove just one. So, which one is truly faster, easier, more "repairable", more rigid, etc.?

[kg]

probably the worst amp i ever worked on in my life was a 1960 vintage vox ac30 head.

[R.G.]

probably the worst amp i ever worked on in my life was a 1960 vintage vox ac30 head.

Hah! Go try a V1141 Thomas Vox Beatle! It managed to be everything wrong about both PCB *and* point to point wiring.

About all the missed was board-mounted jacks and pots, probably only because board mounted pots and jacks were not easily available then. They even used solid core wire, stripped with mechanical strippers to give you a nice stress-crack-starting nick in the wire right at the end of the insulation on each of the several thousand wires.