Products > Test Equipment
RPL1116 (MSO1000Z) and PLA2216 (MSO5000) Active Logic Probe teardown
SilverSolder:
I would love an assembly service, even if it was just for the passive components.
dren.dk:
I finally received the updated PCBs monday and yesterday we assembled two sets.
There's a photo of the frame just before going into the the oven.
We took a flir image of the board after letting it run a little and it seems the solid ground plane does it's job and is very much needed as the comparators still got up to over 60 degrees even with the copper plane spreading the heat.
Two things of note about the boards and stencil from https://jlcpcb.com/
* One via on one of the pods was disconnected, so we had to run a wire, I checked out a couple of the other boards, but did not find the same problem, so it's certainly not a design problem. Perhaps I'm pushing capabilities by using 0.3 mm via holes and would be better served with 0.4 mm drills and larger pads in future designs.
* I wanted to have alignment holes in the stencil, but for some reason jlcpcb ignored my paste gerbers and produced a stencil from the soldermask, thus handily ignoring my alignment holes that I designed into the stencil, drilling those holes was super fiddly.
I remember reading about the stencil problem, but it slipped my mind when I placed the order; aparently the way to getting the stencil you want from JLCPCB is to order the stencil separately from the PCB with only the paste gerbers in the zip file.
dren.dk:
Note also that the scope itself gets quite toasty, I wonder what this will do for the life time.
One of my collaborators is in the process of designing a 3d printed case which will be printed with slightly conductive filament and get lightpipes for the LEDs and a bottom covered by an 1mm silicone sheet.
TK:
In my opinion the LEDs should be removed from your design, they don't add any information to the end user and can be distracting. They might be useful only after assembly if you just want a visual confirmation of the rails being there, but it is adding complexity and power consumption to your design.
dren.dk:
I see, good thing we didn't make it for you then.
Beside your personal preference, everything you said is just plain wrong:
0: If someone wanted to build one of these pods, then it would be very easy to leave out the offending parts and the space they take up was added to be able to have proper mounting holes, so there's no disadvantage to removing the option.
1: The LEDs show the current threshold voltage, so it's easy to notice if it has been set incorrectly, without digging down to the appropriate menu on the scope.
2: IOW: the LEDs do not show the power rails are there, but rather make critical information more readily available exactly where it's needed.
3: The added complexity is 2 extra BOM items (LEDs and micro controller, the resistors and the decoupling cap are the same as other items already used) in total it's 10 extra parts, the total number of parts on a pod is around 50.
4: Seeing as how the comparators dissipate enough power to reach 60 degrees, nobody is going to notice the extra 10 mW taken by the microcontroller and a led.
Now, if I was building a mass-market product, then bean counters might force me to drop the reference-voltmeter option or start optimizing away decoupling caps, but as there is probably never going to be built in more than 5 of these sets, then cost optimization is not at all a priority.
The most important priority is that I build what I want, especially when the cost is basically zero.
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