IOCREST SATA Port Multiplier - manufacturing f*up  - Page 1
Forum section: electronics / general

author: crisr
author_rank: Contributor
timestamp: August 21, 2013, 11:08:13 pm
content: I had a server with 5 HDDs connected through an IOCREST SATA 5x1 Port multiplier. Last week all of them disconnected, and I eventually traced the failure to the port multiplier card; the hot-spare card I had on the server had failed as well. As they were out of warranty (only one month over the 3 month warranty), I ordered a new one.In the mean time, I tried to diagnose the failure, and began measuring the voltages. The board uses aJMS393JMB393 chip, which, according to the (very limited) datasheet, requires 1.3V for the core and 3.3V for I/O. The 1.3V switching regulator was fine, but the linear 3.3V was outputting almost 5V (from the PC PSU 5V rail).Looking closer I saw it was an AMS1117-3.3 in SOT-223 package; however, the GND pin, instead of being connected to GND, had a 330R resistor to GND and a 200R resistor to VOUT! That is, the board had been designed to use a LM/AMS1117-ADJ regulator, but had been fitted with an AMS1117-3.3!!! The 200R / 330R resistor combination is the exact combination to get 3.3V out of a LM1117 adjustable version! How could they make such a mistake? The board even had a "Q.C. Passed" sticker (yeah, right)!The result was that after a few months of usage, the main chip went under. I was lucky that the HDDs and mainboard SATA controller took the 5V I/O without frying as well!The new board I ordered also had the same manufacturing defect! Before turning it on, I took out the resistors and replaced the one that went to GND with a jumper, so now the regulator outputs 3.3V to keep the SATA chip happy.So, now in addition to checking every made in china wal-warts, we have to check computer cards as well just to see if they f*dup the voltage regulators!

author: free_electron
author_rank: Super Contributor
timestamp: August 22, 2013, 12:05:52 am
content: You mistook those little oval labels with 'QC' for Quality control.In reality it stands for Questionable Crap ...

author: G7PSK
author_rank: Super Contributor
timestamp: August 23, 2013, 05:18:48 pm
content: My experience is that the more of those gold QC stickers there is on a product the worse it is, not sure if it's a case of they think the stickers make the thing workor they are trying to convince the purchaser it's all good.

author: Bored@Work
author_rank: Super Contributor
timestamp: August 23, 2013, 05:24:27 pm
content: And the real sad part comes when you try to report such failures to the manufacturer, the importer, the retailer or anyone else who should care. And then you figure out they all give a flying fart.

author: free_electron
author_rank: Super Contributor
timestamp: August 23, 2013, 07:17:20 pm
content: Quote from: Bored@Work on August 23, 2013, 05:24:27 pmthey will most likely tell you : you opened it so warranty is void....

author: crisr
author_rank: Contributor
timestamp: August 23, 2013, 07:49:39 pm
content: Quote from: Bored@Work on August 23, 2013, 05:24:27 pmExactly... it was like "It's out of warranty, so we can't cover it", even though the cause of failure was undoubtly a manufacturing error! I told them that since they sold others, and some are still in warranty, the should issue a recall, since the problem can be corrected before failure, but (you guess): pffffff!

author: calin
author_rank: Regular Contributor
timestamp: August 28, 2013, 09:16:40 pm
content: This is where you are wrong .. their product is not defective ... is just used by an un-aproved user which is just simply too smart to use their POS . Warranty does not covers smart usersGold QC stickers are for "good" buyers that do not not know what a resistor is.

author: amyk
author_rank: Super Contributor
timestamp: September 02, 2013, 01:31:20 pm
content: Quote from: crisr on August 21, 2013, 11:08:13 pmBOM error, something QC probably won't catch if it's along the lines of "plug it in and check that it works" (which it did, and would've kept working even after a 24h burn-in) and not "measure all the voltages". On the other hand, now you have an idea how long a part designed for 3.3V will last when overvolted (usually 4.6V is the absolute max for these) --- just long enough to get past warranty