Products > Test Equipment
RPL1116 (MSO1000Z) and PLA2216 (MSO5000) Active Logic Probe teardown
Noy:
Hi, can you please provide your mouser project cart?
Which tolerance class 1% or even better for the resistors?
Which condensator C0G or X7R?
Some of the measured values in the schematic aren't E series..?
dren.dk:
I ordered almost all of the parts from https://lcsc.com so they could be shipped with my pcbs from https://jlcpcb.com.
The Mouser order contained:
https://www.mouser.dk/ProductDetail/926-LMH7324SQ-NOPB
https://www.mouser.dk/ProductDetail/649-221121-00026T4LF
https://www.mouser.dk/ProductDetail/855-M50-3301342
https://www.mouser.dk/ProductDetail/200-ESQ12523LD
I picked X7R caps and 1% resistors.
I've attached the BOM export from LCSC.
I see now I ordered 200 extra LEDs by mistake, good thing they were so cheap:)
nimish:
--- Quote from: dren.dk on March 07, 2019, 01:15:43 pm ---I ordered almost all of the parts from https://lcsc.com so they could be shipped with my pcbs from https://jlcpcb.com.
The Mouser order contained:
https://www.mouser.dk/ProductDetail/926-LMH7324SQ-NOPB
https://www.mouser.dk/ProductDetail/649-221121-00026T4LF
https://www.mouser.dk/ProductDetail/855-M50-3301342
https://www.mouser.dk/ProductDetail/200-ESQ12523LD
I picked X7R caps and 1% resistors.
I've attached the BOM export from LCSC.
I see now I ordered 200 extra LEDs by mistake, good thing they were so cheap:)
--- End quote ---
Assuming this works do you plan on assembling these for sale?
dren.dk:
That's a hard question.
The raw BOM cost at 10-off numbers is around 100 EUR and that's without hooks and cases.
The sale price a PLA2216 is 300 EUR, so there's certainly room for saving a bit of money, but at low numbers the cost of assembly, shipping and other overhead quickly eats up any savings.
For me it looks as though it's viable to build my own as long as I count the time spent as hobby-time.
If I were to count the time spent as work-time I'd probably have to jump to a production run of at least 1000 units assembled professionally, possibly with custom cases and probes, but that's a huge investment that I have no way of making.
One option to fund the production run would be to set up a kickstarter to ensure the customers are at hand before starting the factory.
Another concern is that I suspect there aren't enough cheapskates with MSO5k scopes in the world that would be willing to plunk down 150 EUR for a knock-off LA probe.
All of this applies to my current design which is more or less a straight clone with a slightly cheaper, but equal performance, comparator chip and the split-pod physical layout.
The connectors and comparators make up 85% of the BOM cost out of that about half is the comparators part.
To make a truly low-cost alternative someone would have to put in the legwork to attack the BOM cost at the expensive end:
1.a: Connector cost could be slashed by finding the parts at the source in .cn in stead of Mouser, I suspect waltzing down to any market and browsing stalls in the pearl river delta would yield massive savings:)
1.b: Another option could be using off-the-shelf consumer cables, but I don't know of any modern standard with 8 LVDS pairs, ground and 4 extra power wires, so that's probably not going to happen.
2: Lower performance comparators must exist, but likely with single-ended output, so one would have to find a cheap LVDS transmitter to pair it with.
bmx:
That's exactly what I had in mind since the beginning of this thread: Is the rigol price really high? No sure, considering it comes with ``quality`` hooks.
It's pretty hard to find good hooks that don't cost a finger each.
After initial disassembly of the pod, everyone noticed quality components inside, compact design, etc. I'm not quite sure at all rigol makes profit on those probes. All in all, fpc, board, case, cables, hooks, labels, lead time, packing and shipping, it's not worth it.
Unless someone reports on quality inspection of the rest of the rigol probe (plastic, leads, heat resistance, hooks, ..) as a $5 piece of crap.
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