ON THE BENCH TODAY: Modded TK Siglent MSO --> HP Pod Adapter
So the boi brings in the mail, and my eBay package is in it. One HP Pod #7, complete with original baggities. The tails for the clips are a bit stiff, but the coax are all still nice & supple. Included were a full set of 16 HP grabbits, all delightfully tiny and smoooth like buttah.
Suhweeet! Now I just need my adapter PCB...
mnem
Last week I received my package from eevBlog member TK; to my surprise, he included two adapters. One complete and assembled, and another in components. Guess he was feeling generous.
TK's adapter posted in the Siglent SDS2000X thread:
https://www.eevblog.com/forum/testgear/siglent-sds2000x-plus-coming/msg3079002/#msg3079002My intent is to use TK's adapter PCB directly with the HP LA pod, bypassing the HP braided cables, as I don't need to be able to reach around to the back of a 1-2U rack-mount boat anchor.
I'm hoping this will work similarly to TK's project; as the HP Pod cable ends themselves incorporate a compensation/tip isolation network, I'm pretty sure it should be reasonably safe to use this way.
The leads on the pod are 13"/330mm long; add the body of the pod and adapter and that's 15"/380mm from the front of the scope. This is more than enough reach for most any of my tinkery projects; the last I used a LA it was with flight controllers I was kibbutzing on that were 35mm square.
To do this, I'll be edge mounting a 2x20 0.100" socket header; this can be achieved instead of the normal 90° TH orientation by using the following technique.
First step is to prep the PCB so that one row of pins can reach the inner row of TH vias. To this end, I've ground ~3-4mm off the edge of the PCB; right down to the edge of the first row of TH vias.
Next, I need to trim the pins on one row of the socket header; these will be soldered to the outer row of TH vias. I hold the header in place, then score across the pins with a knife to make witness marks I can follow with my flush cutters to make a nice neat line of pins.
But before I start soldering, I put a strip of Kapton tape over the outer row of holes on the opposite side. This is to keep the solder from bubbling through the TH via and shorting the pins on this side.
Here I've trial-fitted the socket header on the PCB; you can see now how the pins align with the TH vias. Note that the short pins go on the side of the PCB with the silkscreen printed on it. If you put it the other way, not all of the inputs will work, as the pin assignments are offset. Next I'll tack the end pins in place; I'll do this while pressing down on the socket header so the pins are tight against the PCB.
If I've done the work right, there will be a nice ~0.5mm air-gap between the pins on the other side and the PCB. This is perfect, since these are the signal pins.
And here's the finished adapter after scrubbing with IPA and a toothbrush; nice tidy soldering if I do say so myself.
The Money Shot!Here I've alternated inputs on my Cheap & Cheerful Chinesium™ PWM generator and the Cal signal from my T3DSO2102; like DefPom, I'm not exactly pleased with the way it puts D0 under/between D13 & D14, so I just turned D0 off for the demonstration.
One thing that is a bit annoying is that without the braided cable, the pod has to be plugged in upside-down. This means that there is no legend, and the numerical order is bass-ackwards. Fortunately, a little heat from a hot air gun is all that's required to peel the label off, with adhesive intact...
...and applied to the other side. Now all that remains is to design and print a plastic shell so the adapter PCB has support inside the hole in the case, instead of all load being on the connector socket itself.
Cheers!
mnem
*toddles off to RTFM*