General > General Technical Chat
Disappointed with Mouser Customer Service
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Sal Ammoniac:

--- Quote from: Zeyneb on June 21, 2022, 12:00:03 am ---What matters now is how you're going to present this to Mouser in a convincing way.

Just telling them "It's defective" isn't convincing.

--- End quote ---

I've sent them a description of what I found, similar to the description above.
Sal Ammoniac:

--- Quote from: thm_w on June 21, 2022, 12:23:50 am ---
--- Quote from: Sal Ammoniac on June 20, 2022, 11:14:23 pm ---The Hall encoder circuit is simple. There's a 10K resistor in-line to limit current, a 10K pull-up to Vdd (3.3v), a 1nF cap to ground to filter noise, and a Schottky diode to Vdd to clamp input voltages to the Vdd rail. Each of these three circuits (one for each encoder input) then goes directly to an MCU pin, which in the input state is hi-Z. When I put 3.3v on the H2 and H3 inputs (the working ones), I saw 3.3v on both sides of the 3.3K resistor in-line from the input to the MCU. When I put 3.3v on H1, I saw 3.3v on the connector side of H1 and 1.25v on the MCU side of the resistor. Probing directly at the MCU pin, I saw the same 1.25v. The MCU's threshold for a logic high is 1.88v, which would explain why I'm always seeing "0" on that input. Something is pulling down that input, but without removing components from the board, it would be difficult to tell what it is.

According to the schematics, there's nothing else connected to this MCU input pin, and I verified this by looking at the Gerbers. I also verified that all three of the MCU ports associated with the encoder inputs are in input mode with the internal pull-ups/pull-downs disabled.

--- End quote ---

If you check the resistance to ground with the power off, is there a major difference on those two inputs? Directly across the 1nF cap.
Whatever it is is a 0.6mA draw.. so not very much.

Nothing else is connected to those mcu inputs on the schematic right.
Maybe hold the thing in reset and see if injecting 3.3V has the same result. Although, with the pin set as input, should be confident already..

--- End quote ---

With power off, resistance to ground is 13.25K on all three inputs.

Yes, there's nothing else connected to those three MCU inputs. I've tried injecting 3.3v with the MCU held in reset and the results are the same: 3.3v at the two "good" inputs and 1.25v at the "bad" input as measured directly at the MCU pins.
Bassman59:

--- Quote from: Sal Ammoniac on June 20, 2022, 06:08:27 pm ---I bought a development board from Mouser last week and when the board arrived it was defective. I called Mouser customer service expecting them to give me an RMA number so I could send it back for a replacement, but no, they said I’d have to send them a detailed explanation of the issue and they’d contact ST to determine what they wanted to do.

If this were a $15 Nucleo board, I wouldn’t bother—I’d just toss it on the junk pile and move on. But this is a $330 board that I need for a project. Now I have to wait indefinitely while Mouser works this issue with ST. I probably won’t have a working board for weeks.

Is this level of “customer service” common in the industry? I suppose I’m spoiled by Amazon’s no questions asked return policy.

--- End quote ---

Why didn't you take this up with the manufacturer?
hans:
Companies and private customers have different e-shopping rights. In NL too, we can basically send anything back for up to 2 weeks within reasonable usage terms (e.g. just to see if they will suit you, so don't wear clothes to a party and then send them back)

I've heard stories about *several* 5k$ FPGA boards being sold to my university, that were then a few months down the line picked up for a project. They were all defective in one way or another. Contacted support, they confirmed the issue but 1) Low volume product, bad luck. 2) Apparently waited a few months for evaluation is too long. 3) Not private customer, so though luck.

On top of that, these are technical components.. so unless you have some kind of conversation with the manufacturer that can show your board is indeed defective, then it becomes very hard to proof you haven't read the manual incorrectly (which, by the expectation that manuals are *written* incorrectly, then has a 100% probability of occuring).
Sal Ammoniac:

--- Quote from: Bassman59 on June 21, 2022, 07:38:30 pm ---
--- Quote from: Sal Ammoniac on June 20, 2022, 06:08:27 pm ---I bought a development board from Mouser last week and when the board arrived it was defective. I called Mouser customer service expecting them to give me an RMA number so I could send it back for a replacement, but no, they said I’d have to send them a detailed explanation of the issue and they’d contact ST to determine what they wanted to do.

If this were a $15 Nucleo board, I wouldn’t bother—I’d just toss it on the junk pile and move on. But this is a $330 board that I need for a project. Now I have to wait indefinitely while Mouser works this issue with ST. I probably won’t have a working board for weeks.

Is this level of “customer service” common in the industry? I suppose I’m spoiled by Amazon’s no questions asked return policy.

--- End quote ---

Why didn't you take this up with the manufacturer?

--- End quote ---

Because the company I bought the board from, Mouser, is likely to have much more clout with and access to the right people at ST than I do. If I don't get a satisfactory response from Mouser then I'll contact ST directly.
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