I finished the board and it is flip flopping on the bench. The schematic had the darn LEDs in backwards and I didn't catch it and had to redo them. But, when I shoehorned it into its enclosure things went wonky so I'm still working on it...

What exactly are you building?

 

It's a capacitor tester that connects to the scope. It flip flops the connection from end to end with an LED to indicate which end is being tested. Most modern caps (other than electrolytics) are not marked for outer foil end but can be tested to determine which end it is with a scope and pinching the cap to loose couple it with your bodies noise picked up from the Aether. The noise picked up and displayed on the scope will be higher on the end not connected to the outer foil which acts like a shield when "grounded" to the low impedance end in the circuit. I can be done manually but this kinda automates the process to make it a bit easier. It's a Paul Carson design.

The switch will end up in the hole on the left and yellow wire to the center of the BNC for the scope output.

Once it starts working correctly, I'll add aligator clips to the ends of the coax to hold the DUT.

 

Thinking about hold down methods. Could use some piano wire I have but would have to come up with a base. Molded lead would be great but don't have the means to melt and cast it. Looked on AliX and they have lots of them, mostly without the base but I did find this with the base plate and put it in my cart. Seems to be the best price including shipping. It could have another hold down added but one at a time works for me IF it actually works and has enough tension to keep 0402s in place. I'm thinking of going to hot air so the compnent doesn't get nudged out of position with the hot iron.

 

OK, all done and flip flopping! Oooops, had it switched off when I took the pic!

 

OK, all done and flip flopping! Oooops, had it switched off when I took the pic!

View attachment 310397

Three power supplies, two fancy multimeters, a rather nice two channel scope, and a cool, retro-looking custom device ... I hate your guts .... showoff!!!

 

That doesn't even include my 4-channel Siglent SDS2104X Plus scope, 3 function generators and ole time Heath T-3 Visual Aural signal tracer. The little bit in the upper right is an old Fluke 8050A 4.5 digit DMM that I've calibrated and a Heath VTVM. Lots of goodies. Just went through the 2 old Heath items and rebuilt them with new caps and replaced all the out of spec carbon resistors and calibrated them plus replaced the VTVM battery with a small power supply adjustable voltage module. Still have a bunch of old mostly Heath transceivers and power supplies to do. HW-101s and a Single Bander SSB transceiver plus rebuild my old military TV7A-U tube tester. Lots on my todo list still.

 

You can't beat a good 'mini-lab' when building/testing prototypes

 

Excellent tips here!

I need to solder some Mosfet in the Power SO-10 package which have a large copper area as a heatsink, which also prevents soldering the tab properly with an iron. I will use Y’s sticky flux suggestion and use a large heat gun.

 

I didn't SPICE analyze it as it was from a "trusted" source but I did breadboard it. After I etched the board, I gave it a short bath in Liquid Tin to plate it. Maybe not long enough as I kept having to patch several lifted traces with soldered in resistor leg trimmings. I was part way through the first board when I discovered some missing traces and was unable to patch them. Turned out to be a good thing as I used the partial first board to find the drill positions in the small Hoffman box. It does have one peculiarity, both of the mounting screws to the case have to be tightened down to ground the board. I do not like having 2 grounds.

I'm still in the process of renovating my electronics bench/Ham Radio and etc. station. Cleaned up the cable snake pit behind the bench by adding a board with 4 20A 12 receptale power strips and vesa mounts to get the monitor off of the riser and a couple of corner shelves to get the speakers off of the bench as well. The clock is set to UTC instead of local EST. The second monitor is waiting for its VESA mount and will be used for Ham Radio Deluxe software which is connected to my Icom 7410 and R75 radios for remote control. Used mostly for scanning the bands looking for traffic openings. Not shown are 2 more bookcases and my large bench drill press.

 

Looked on AliX and they have lots of them, mostly without the base but I did find this with the base plate and put it in my cart.

Did you find a good price on just the probes? The best I've found is $9 for 2 probes with $4 shipping (fixed up to 20 pairs).
https://www.aliexpress.us/item/3256...6861e897b!12000036592846852!rec!US!707156758!

 

I got one probe and the base for right at 15USD. Base appears to be drilled and threaded for a 2nd probe but one will do. Not sure if it even works albeit sounds like a good idea. The probe is a pogo pin and the strut that holds it is FR4 or something so there is not that much holding strength. But with hot air instead of poking it with an iron I hope it works better than what I've been doing. I'll see and let you know Dennis.

 

Base appears to be drilled and threaded for a 2nd probe but one will do. Not sure if it even works albeit sounds like a good idea.

The base of the probes are magnets and the base is some ferromagnetic material.

I was thinking about buying round magnets with M3 holes drilled in them:

Then use some #4-40 flat head screws to a 4-40 coupler, then use about a 2" 4-40 screw with nuts and washers to position some arms I was going to make from some unclad FR-4.

Once I priced a steel base and found pairs of probes for $8.50, I decided to buy the probes and use an old 14" circular cutoff saw as the base.

 

There's also this option:

 

Aha! If I'd known that... Looked like it was threaded in. That's a whole nother thing then.

EDIT: I think I like the second option better!

 

Aha! If I'd known that... Looked like it was threaded in. That's a whole nother thing then.

EDIT: I think I like the second option better!

This one is a better price. Item price is a little more, but shipping for 10 is $4. The other one I listed charged more for shipping.

 

That is the solution for the piano wire hold down base that I couldn't figure out how to do. You can put as fine a point on it as you want and the spring tension in the high grade wire is great. Having a magnetic base is a great idea, especially with the rare earth magnets you can get now. Definitely going to give one a try.

EDIT: Best I could do was 9.06USD with shipping and tax, on order!

 

Something I came up with a couple of years ago it might be of some aid.

200°C SMT Hot Plate

not bad for a gal with only one working hand. Makes it a pain to solder though.

 

DIT: Best I could do was 9.06USD with shipping and tax, on order!

I have 10 in my cart for $59.30. $5.70 each, $4 shipping, seller discount, and coins. Might remove 2-4 before I order...

Going to see if I can find a listing participating in the shop and save promo of $3 off every $20.

 

More holder ideas:


https://www.aliexpress.us/item/3256...1963efa61!12000022458203954!rec!US!707156758!
I'll be looking for some of those flexible holders.