Test Equipment Anonymous (TEA) group therapy thread

[bd139]

I wouldn't use a spot cutter. You end up with lots of little bad quality capacitors with everything else underneath the board as demonstrated here



The manhattan pads, while capacitors are quite stable in HF at least.

[tggzzz]

Speaking as another person who is baffled by the complexity of RF, how do you make the connections on the copperboard that aren't ground, do you use some form of stick on pad or something because it clearly is not a printed circuit? 

For many ideas, see
http://bristol.hackspace.org.uk/wiki/lib/exe/fetch.php?media=skillshare:solderlessbreadboards02-03.pdf
http://bristol.hackspace.org.uk/wiki/lib/exe/fetch.php?media=skillshare:solderlessbreadboards03-03.pdf

[Mr. Scram]

I don't do well in heat/humidity either.  I am here because by ex-wife got me to move here.  She wasn't my ex when that happened.  I liked the idea of moving again even less than the heat.  Now, at this point, I am too old to start on the bottom rung of the ladder at another company and right now there is no other state program I can move to with my company.  If we ever actually get a chance to retire, it will be somewhere there is at least 3 seasons.

Is that a US thing, having to start over again when moving to another company? Even if you don't have all the proper credentials you should have enough of a proven track record right, right?

[Mr. Scram]

Most of the China-direct sites are now offering small CNC router tables for cheap... I keep thinking all that's really needed for fast small-run PCB fab is some DECENT, reasonably accurate open-source software to "carve away everything that isn't a circuit" on DS FR4.

I've seen some startups TRYING to do it, but the actual solutions are no where near as "ready for prime time" as 3DP is, and they're crazy expensive for the half-baked product they do have.

I may actually live long enough to see something that works.

mnem
*p00t!*

The problem tends to be the rate at which relatively expensive bits get eaten up. Most people who experimented with the technology seem to have been disappointed or moved on to something more convenient.

[Specmaster]

Speaking as another person who is baffled by the complexity of RF, how do you make the connections on the copperboard that aren't ground, do use some form of stick on pad or something because it clearly is not a printed circuit? 

You start with a sheet of FR4 single sided substrate copper side up. Then you stick strips (cut with some Wiss shears) on to the surface with superglue. Solder parts on to the strips or the ground plane. Commonly called Manhattan construction.  You don't have to do it this way but it leads to a solid ground plane which is very important and doesn't require etching a board and looks relatively neat (which is important if you're OCD like me )

This isn't specifically for RF - even really slow circuits can do funny things without decent ground planes and construction etc.

Here's one I did earlier with a better angle. Looks pretty neat but in this case, performs terribly 



Edit: main reason is it's bloody cheap. 100x160 boards are about £1.40 from Rapid. Get through about 5-6 a year: https://www.rapidonline.com/rvfm-copper-clad-double-sided-fr4-fibre-glass-board-100-x-160mm-34-0820

Thats pretty much what I thought your board looked like but I wasn't sure as it was cropped and lost detail a bit but it makes sense and it also allows for fairly large pads for connection so you could have multiple connections from the same point if the circuit demanded it, neat. I might even have a go myself one day although I doubt it would be anything to do with RF 

[mnementh]

I never saw the point of those CNC tables for PCBs. Too much complexity. I actually made a fair chunk of PCBs in my time, going back to secondary school, using photoresist + UV which is pretty cheap and easy. If it's a really simple one shot, just draw the damn thing out with a marker... works down to 0805 / SOIC at least....

Edit: this was a 3 hour turnaround including the design and construction...

         

Even the parts for that one were recycled off a duff HP scope, apart from the AD8307 which was aliexpress gold.

(forget controlled impedance etc - good enough for HF / low VHF mainly)

I've made more PCBs than I can count from many methods, including using a ditto machine back in the day and laser printer photo-resist. There simply isn't anything really convenient to turn out something small quickly. I'm tempted to try and do it using a 3D Printer to create the resist; just as a proof of concept. Even that could dramatically improve the quality of the product and drastically reduce production time.

The problem tends to be the rate at which relatively expensive bits get eaten up. Most people who experimented with the technology seem to have been disappointed or moved on to something more convenient.

As I said, the solutions out there are not yet ready for prime time. In commercial applications it is a mature technology; there are a number of short-turnaround fab houses which make their boards this way already. The problem is the piss-poor quality of what is being produced as inexpensive CNC tables vs similar price range 3DP also being made of 8020 extrusion; it's like they learned NOTHING from the explosion in 3DP. 

Speaking as someone with a fair amount of machining experience, bits getting eaten up is caused by poor quality machines and not running at the correct feed speed for the spindle speed, which is ALSO caused by poor quality machinery (and software) that doesn't have a decent motor and speed control.

This is STUPID, as I can buy a good quality BL Motor that will develop 1/2 a HP AND the speed control to run it, some of which can even be programmed with governor FW, for ~US$20 combined. Sometimes less, if it's on sale. Yet they STILL insist on trying to make this stuff work with steel can brushed Mabuchi motors. 

As a prototyping/one-off solution, I believe it could be easily brought in under $200 (which I'd gladly pay, if usable software was available) with 8020 extrusion construction; the weak point is the software, which at this point is barely better than trying to write gcode from a text editor.  We need something like Cura to take Gerbers and Eagle files and make the GCode for a small router table.

That said, I still don't believe it would be good for anything even remotely approaching production quantities.

mnem
*taxified*

[bitseeker]

Fluke 8050A with US shipping rates (same item);
https://www.ebay.com/itm/132817412734

Now that makes more sense. That's a decent price (read: cheap  ). It's very tempting but having a hard time justifying it when I already have one plus 4 other Fluke bench DMM's. 

Edit.....someone buy it before I do! 

That's a pretty good price. However, I think I'll pass because:

1. Seller has only 98.7% positive feedback rating; 96.5% in the past 30 days. From reading the neutral and negative comments, looks like customers are their unsuspecting QA department.

2. I like my Fluke 8100A.

[GreyWoolfe]

I don't do well in heat/humidity either.  I am here because by ex-wife got me to move here.  She wasn't my ex when that happened.  I liked the idea of moving again even less than the heat.  Now, at this point, I am too old to start on the bottom rung of the ladder at another company and right now there is no other state program I can move to with my company.  If we ever actually get a chance to retire, it will be somewhere there is at least 3 seasons.

Is that a US thing, having to start over again when moving to another company? Even if you don't have all the proper credentials you should have enough of a proven track record right, right?

It has happened to me in the past.  Luckily, I only lost a little bit of money from my old job to this one.  I did come out ahead as the company is no longer active in Florida so I would have been RIF'd (reduction in force).  By the time I got the new gig, I had already met and proposed to the current Mrs GreyWoolfe and she had already moved to Central Florida whilst my new job moved me from South Florida to Central Florida so we could be together.  Now, I am over 60 and it is harder to start over.  A ham radio friend was a Unix Admin for many years and was RIF'd himself.  He struggled to find work as he is also over 60 and is now trying to build up a photography business whilst delivering human organs and things.

[med6753]

Fluke 8050A with US shipping rates (same item);
https://www.ebay.com/itm/132817412734

Now that makes more sense. That's a decent price (read: cheap  ). It's very tempting but having a hard time justifying it when I already have one plus 4 other Fluke bench DMM's. 

Edit.....someone buy it before I do! 

That's a pretty good price. However, I think I'll pass because:

1. Seller has only 98.7% positive feedback rating; 96.5% in the past 30 days. From reading the neutral and negative comments, looks like customers are their unsuspecting QA department.

2. I like my Fluke 8100A.

I checked it out and didn't realize that I have bought from this seller before. A Tek 7A15A Vertical Plug-in. It was also cheap and it works fine. But I'm gonna pass on this 8050A too.

[mnementh]

I'm gonna pass because A) I already have more meters than I know what to do with and 2) I've had that 3478A crying for attention on the back corner of my bench for most of a week now, barely visible under a sea of tax paperwork. It's quite pitiful, actually. 

In Other News...

It may be exhaustion talking, but I believe I actually have our taxes done. I've tabulated all my piles of receipts, and I have some extra categories that may help and oodles of mileage to claim... and I even have some positive data from my student loans that should polish this turd a little more.

Tomorrow afternoon's appointment with our tax agent will put the metal to the grindstone, and we'll see what all my misery was worth. 

mnem
Everybody needs something to believe in; I believe I'm going to bed.

[URI]

mnem
Everybody needs something to believe in; I believe I'm going to bed.

Good night!   

I've packed my DSO-X 3034A last night 'til 01:00 because I started late.
I'll deliver it in roughly about an hour to UPS to let them carry it to Keysight Germany.   

I salvaged the packaging material from several items I got over the last months.
Now I know why I saved this pile of cardboard packages and stuffing materials from the dumpster.
My wife wasn't happy about this.. 

But now I have no choice any more..      

[capt bullshot]

... you could use mini striplines with proper impedances up to 23cm:

https://electronicprojectsforfun.wordpress.com/prototyping/

scroll down a bit to see a tuned amp that works OK.

I've build a bit of RF stuff using that 1.27mm raster protoboard, it has a solid ground plane at its backside.
It's not specified in any way, but running a longer trace by connecting a row of the small squares results in near enough to 50 Ohm impedance for things to work.

[bd139]

That stuff always looks interesting but I can’t bring myself to pay for it

[Specmaster]

Heads up anyone in the Midlands, UK. If you fancy a Telequipment D83 going cheap and looks in reasonable nick, check this link out, there are 3 on offer for just £65 for the lot. https://en.shpock.com/i/W8QtGDAQjjXjZN8Q/

[bd139]

That's a lot of scopes 

[Specmaster]

Yep, and don't forget to take your carrier bags as well 

[bd139]

Hahaha 

I've cancelled that. Screw it. Keeping them.

[med6753]

They're too heavy, I can't lift them. 

[Specmaster]

Hahaha 

I've cancelled that. Screw it. Keeping them.

Well, grab these 3 as well and arrange them all in a pattern so that when you aren't using them, they could become your dining table. I'm sure SWMBO would love a distinctive table like that, a designer table, start a new craze right there. 

[bd139]

I did consider something like that.

BTW as the second unit is parts mule I've set myself the challenge of building a receiver out of the left over bits excluding some FR4 and an enclosure. Reckon I can do it.

[Cerebus]

That stuff always looks interesting but I can’t bring myself to pay for it

Well, as I've said before: PCB runs are now so cheap that if you want a protoboard it's probably cheaper to get the Chinese to custom make that protoboard than to buy one off the shelf.

[Cerebus]

They're too heavy, I can't lift them. 

In my mind I'm seeing a Rocky style training montage with someone bench pressing two scopes tied to the ends of a broom handle...

[med6753]

They're too heavy, I can't lift them. 

In my mind I'm seeing a Rocky style training montage with someone bench pressing two scopes tied to the ends of a broom handle...

Apparently the kid who showed up at bd139's place couldn't bench press a flea. 

[Specmaster]

They're too heavy, I can't lift them. 

In my mind I'm seeing a Rocky style training montage with someone bench pressing two scopes tied to the ends of a broom handle...

Apparently the kid who showed up at bd139's place couldn't bench press a flea. 

No, but she could carry two carrier bags though 

[bd139]

She seemed the sort of person who when the shopping arrived would shout out of the window "kitchen is on the 3rd floor, I'll buzz you in".