EEVblog #860 - Mailbag

[EEVblog]

Mailbag Monday



SPOILERS:
Supermicro AMD Opteron Server Motherboard
http://www.supermicro.com/Aplus/motherboard/Opteron6000/SR56x0/H8QG6-F.cfm
http://support.amd.com/TechDocs/44549.pdf
http://support.amd.com/TechDocs/43869.pdf

Ibico & TI calculator teardowns

Cheap Multimeter Teardowns

Perf2 Prototype board crowd funder:
https://www.crowdsupply.com/ben-wang/perf-2

Garmin GPS III+ Teardown
Radio Shack Pen Oscilloscope Teardown
COP8 Microcontroller: http://www.datasheetarchive.com/dlmain/Datasheets-22/DSA-430223.pdf

[Brumby]

Definitely agree ... that server board should be framed - or under a glass topped coffee table.

[Fungus]

12 layer board?    What would all the layers be?

What's the most layers anybody's seen in a board?

[bktemp]

Böblingen is a town near Stuttgart.
Interesting to see the hand held scope was made by Wittig Technologies. They also made the infamous W2000 scope, probably one of the worst scopes ever.
At least the company name seems to be still alive and they (or a different company who bought the name) still produce handheld scopes:
http://www.wittig.it/history.html

[EEVblog]

What's the most layers anybody's seen in a board?

I've personally done 22, or was it 24 layers 
Too many years ago...

[SteveLy]

Those super-dodgy meters at the end were too funny. I cracked up big time +/- 2dgts indeed!

[coppice]

What's the most layers anybody's seen in a board?

I've personally done 22, or was it 24 layers 
Too many years ago...

I used 22 layers many years ago, but the boards were very thick. I saw some fairly thin 22 layer boards recently. Each layer must be extremely thin.

[krivx]

What's the most layers anybody's seen in a board?

I've personally done 22, or was it 24 layers 
Too many years ago...

I used 22 layers many years ago, but the boards were very thick. I saw some fairly thin 22 layer boards recently. Each layer must be extremely thin.

Any idea on thicknesses? I've seen quite a few 15-20mm thick boards recently, no idea on layer count.

[woox2k]

12 layer board?    What would all the layers be?
What's the most layers anybody's seen in a board?

Haven't seen one personally but Mike tore down a 30 layer board: https://youtu.be/RHqN6CTOdzA

[SeanB]

What's the most layers anybody's seen in a board?

I've personally done 22, or was it 24 layers 
Too many years ago...

I used 22 layers many years ago, but the boards were very thick. I saw some fairly thin 22 layer boards recently. Each layer must be extremely thin.

How about a 28 layer flex pcb stack, used to connect a backplane to the circular bayonet connectors on a front panel. With care you could actually unsolder them and reuse when changing a connector. Luckily for us there were quite a few pins that were either no connection, or were redundant grounds for shielded cables, so breaking a pin was not always a train wreck. Only issue was that resoldering could only be done with the pack reinstalled in the case and bent into the right orientation. Weller DS701 earned it's keep with that job.

[Stebanoid]

EEVblog, this traces on the motherboard under memory slots are not memory traces, they are inter-CPU data link. And I'm surprised that they are length matched, because serial multilane busses have internal mechanism, eliminating need in trace length match. Why it's done here anyway?

[Kilrah]

Interesting to see the hand held scope was made by Wittig Technologies. They also made the infamous W2000 scope, probably one of the worst scopes ever.

Had one, and I agree 

[Mr.B]

Definitely agree ... that server board should be framed - or under a glass topped coffee table.

Like this one?

It is an old Dell PE2850 as a coffee table in my office at work.

[Brumby]

Can you play "Space Invaders" on it?

[Mr.B]

You could have when it was a server... 
I gutted the power supplies and removed the HDDs to make it a lot lighter.
I added a hand full of LEDs and an MCU to flash the LEDs randomly.
Powered by the 5v wall wart you can only just see top left.

[tszaboo]

Can you not send any more sub 5 dollar/Euro/Yankee dollar multimeter to Dave please? Send him something nice.

[Towger]

Can you not send any more sub 5 dollar/Euro/Yankee dollar multimeter to Dave please? Send him something nice.

I have a broken military Avo I must send, it built like a brick dunny so weights several Kg.  It also has a very strong old musty electronics smell, but the less said about that the better.  It was one of my worse ebay purchases, sold for parts but someone else had a go at fixing it first and destroyed the movement :-(

[viila]

Can you not send any more sub 5 dollar/Euro/Yankee dollar multimeter to Dave please? Send him something nice.

I dunno, that "digital" analog meter was good for a laugh...

[SeanB]

I was at Luft fans the other day, and they are using a massive inline air blower as a table, simply by putting some rubber feet on the top and bottom and putting a 1in thick glass sheet as a table top on it. I asked them if I could plug it in and try it, though it probably would have sucked up the carpeting.

Did get the fan I came for though, though I was also temped by the 450mm floor standing fan, but I have already got one that I bought as scrap. A little work with a hammer, some wire to fix the cage, a few new screws and it runs good enough.

[Harrkev]

So, where DOES one get a cheap analog meter for $1 US?  I have tried eBay and Ali Express, and everybody wants at least $4 or $5 for similar meters.

Yeah, I know -- junk.  However, I used to have a similar one from Radio Shack when I was a kid -- nostalgia.

[rrinker]

 Harbor Freight. Watch for coupons and you can get one FREE! I only have like a half dozen of the little buggers. All the ones I have use button cells, not a 9V, so it's often cheaper to just get a new meter when the batteries die. They work great for my low voltage model railroad stuff, plus if I drop a hammer on one, or a soldering iron, it's no big loss.
                 

[Harrkev]

Harbor Freight. Watch for coupons and you can get one FREE! I only have like a half dozen of the little buggers. All the ones I have use button cells, not a 9V, so it's often cheaper to just get a new meter when the batteries die. They work great for my low voltage model railroad stuff, plus if I drop a hammer on one, or a soldering iron, it's no big loss.

Not the digital meter, I mean the analog one.

I have a couple of Harbor Freight digital meters, and they work just fine for low-voltage stuff.

I don't actually own an analog meter of any sort right now.

[rrinker]

 Hmm, I haven't seen a new analog meter for sale in ages. There was a tool place that used to sell an analog one and a digital one, the digital one was the same as the HF one, and they wanted something like $15 for them. I just laughed. But they also had a tiny cheap analog one as well, same price I think.
 My first meter was the itty bitty Radio Shack analog one that was half the price as a kit, so I got the kit version and built it. Banggood has an analog meter for $3.93, free shipping and no tax. That's the cheapest I can find with a quick search.

[Orpheus]

So, where DOES one get a cheap analog meter for $1 US?  I have tried eBay and Ali Express, and everybody wants at least $4 or $5 for similar meters.

Yeah, I know -- junk.  However, I used to have a similar one from Radio Shack when I was a kid -- nostalgia.

I had a long nostalgic story I was going to tell, but I'll spare you. Short strokes: to get $1 prices in the US on anything other than a lucky find, shop for a "lot" --  you may find 10units/$10 (or something smaller) 1u/$1 is not worth the time/effort to process. They won't be easy to find [I ordered 100s for a gifted children's program in the late b1970s, and they surplus supply was already drying up), but eBay, TauBau, Alibaba etc. must have them today, given that Someone found one as "new stock" in an African shop (IIRC) to send Dave

[zal42]

So, where DOES one get a cheap analog meter for $1 US?  I have tried eBay and Ali Express, and everybody wants at least $4 or $5 for similar meters.

I'll tell you my secret source for cheap gear and parts, although feasibility might vary depending on where in the US you are. We have a local nonprofit. electronic re-use shop (a bit like Goodwill, but just for electronics) that mostly refurbishes and resells computers and complex things like scopes. They always have boxes of common doo-dads like "obsolete" meters (and mice, cords, etc) that they sell for 50 cents to a dollar each.

I've also had reasonable luck secondhand stores that aren't specifically electronics oriented. Goodwill, etc. When I need a new piece of equipment, the very first thing I do is make the rounds through these places. 75% of the time I find what I need for pennies on the dollar.