1. Home
  2. Electronics Design
  3. Rant - Bad (Chinese) engineering

Rant - Bad (Chinese) engineering

Over the Christmas break I've been remote debugging a project in China, their design not mine. The supposed design engineer is beyond useless.

The circuit had 3 2N3904 BE junctions connected in parallel to a single common base resistor.

To protect the transistors from reverse voltage a schottky diode had been fitted between the emitters and the common point of the circuit.

Presumably because not all the transistors switched on a resistor had been added in parallel to each of the diodes.

The circuit is controlling a pair of back to back mosfets. Because the circuit did not work when 1 of the FETs one of the 2N3904 had been added across the FETs to ensure a current flowed while the FETs were off!

So the shutdown power mosfet had a small signal transistor across it. I was puzzled why the transistor had not fried. Too low a voltage diiferential to drive enough current? No. The base current was less than 10uA and the low gain of the transistor meant that only about 1mA could flow.

I'm making progress because the test guy is OK, the design guy is just a hinderance.

They've shut down for the night so back to my own project.

/end rant

Reply to
Raveninghorde
Loading thread data ...

Violating EE101 :-)

[snip]

Can the Chinese actually _design_ anything? All I've ever seen them do is _copy_. ...Jim Thompson

--
| James E.Thompson, CTO                            |    mens     |
| Analog Innovations, Inc.                         |     et      |
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
| Phoenix, Arizona  85048    Skype: Contacts Only  |             |
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  |
| E-mail Icon at http://www.analog-innovations.com |    1962     |
             
I love to cook with wine.     Sometimes I even put it in the food.
Reply to
Jim Thompson

I had to look up EE101. But yep.

formatting link

They've got the world's fastest computer with their own design of back bone.

Reply to
Raveninghorde

That is a dangerous assumption. Remember when the big three in Detroit scoffed and laughed at the first VW Beetle? That blissful ignoring of potential competition stopped rather quickly, in fact it led to serious financial troubles.

Some of the tools I have here, such as a scope, indicate that folks in Taiwan and Mainland China can design. I've opened many from Tek and haven't seen anything like it. Same with a function generator which has some features I've never seen in the usual ones. Yeah, it does have quirks so they aren't close to perfect yet but usually that is only a matter of time.

--
Regards, Joerg

http://www.analogconsultants.com/

"gmail" domain blocked because of excessive spam.
Use another domain or send PM.
Reply to
Joerg

"Jim Thompson" wrote in message news: snipped-for-privacy@4ax.com...

Why design when it's cheaper and more profitable to copy? :-)

Their political system possibly means that there are more incompetent guys holding the title of "engineer" than there would be in the U.S., I suppose -- but there surely are plenty of highly competent guys in China too. Heck, all the low-end test equipment from Tek and Agilent is now manufactured and usually designed in China, and they still have a very hard time competing against the likes of Rigol (mainland Chinese) and Instek (Taiwan).

---Joel

Reply to
Joel Koltner

When was the last time Tek designed a scope?

--
For the last time:  I am not a mad scientist, I'm just a very ticked off
scientist!!!
Reply to
Michael A. Terrell

Now that is *scary*.

I've found that none of them can be trusted (almost surely a management issue). Tek must have some serious quality people watching over their every move.

Reply to
krw

Yeah, I 've heard that... I think Spehro has mentioned it as well. I suppose it is just the cost of doing business, but it makes it more difficult for smaller companies that can't afford to station one of their guys semi-permanently in China.

I expect Apple has a lot of their own people on-site at Foxconn!

Reply to
Joel Koltner

I am pretty sure they are designing some right now, in the >$10k class. But it seems that some of the lower end ones got screwed up.

--
Regards, Joerg

http://www.analogconsultants.com/

"gmail" domain blocked because of excessive spam.
Use another domain or send PM.
Reply to
Joerg

Then how did the TDS2xx recall come about?

--
Regards, Joerg

http://www.analogconsultants.com/

"gmail" domain blocked because of excessive spam.
Use another domain or send PM.
Reply to
Joerg

Absolutely, but we keep trying anyway (stupid).

You bet! An army, undoubtedly.

Reply to
krw

None of the guys from Tek who supervised the Chinese engineers were that good either? :-)

I mean, it does sound like a design fault rather than a manufacturing/quality problem:

"Tektronix has determined that certain incorrect use of our model TDS 210 and TDS 220 oscilloscopes (which are subject to the recall) may cause the ground connection to fail on these products, potentially exposing the user to risk of serious personal injury or death. If a user incorrectly connects a probe ground lead to a voltage source, or incorrectly touches the ground ring near the probe tip to a voltage source, a circuit board trace in the product's electrical ground path may open. Thereafter, the product may appear to function normally; however, the unit is no longer properly grounded. Subsequent use of the product could then result in a serious electrical shock to the user. We are conducting a recall to prevent this possibility of injury to Tektronix customers."

Maybe they needed a good consultant! :-)

---Joel

Reply to
Joel Koltner

It was a design fault. Just like the noise coming out of those things is.

That sounds like legalese for "we screwed up the design, an accidental oops by the user may leads to a serious fault in the unit, but we don't want to word it quite that"

Don't know about Tektronix but some companies will never grasp the value of consultants, even if only for a second opinion. Some of my clients use me that way and it has prevented quite a few "oh s..t!" situation, and numerous $5k+ EMC re-runs. I can almost guarantee that I'd have found that sub-par grounding trace because it wouldn't have been the first time.

--
Regards, Joerg

http://www.analogconsultants.com/

"gmail" domain blocked because of excessive spam.
Use another domain or send PM.
Reply to
Joerg

Are you getting paid a decent rate? If so, then I'd say milk it - it's like the dream client.

I once had a dream client who was a crackpot. Over the course of just a couple of weeks he paid me over 3K to design components for what was essentially a perpetual motion machine. Of course, with those kind of dollar signs in my eyes, I wasn't about to tell him it was impossible to do what he proposed.

I swear, he had an electric motor that drove both the wheels and a generator, which he claimed would charge the battery while it was under way.

I refrained from enlightening him, because that would have stopped the money fountain. Yeah, I guess I'm a greedy bastard. ;-)

Cheers! Rich

Reply to
Rich Grise

Hmm, I guess you didn't do it right, you only got him for 2 weeks.. Most would at least encourage them for 6 months.. ;)

Jamie

To steal ideas from one person is plagiarism. To steal from many is research.

Reply to
Jamie

How old is this recall? I have a TDS210 and have never received a recall notice. ...Jim Thompson

--
| James E.Thompson, CTO                            |    mens     |
| Analog Innovations, Inc.                         |     et      |
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
| Phoenix, Arizona  85048    Skype: Contacts Only  |             |
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  |
| E-mail Icon at http://www.analog-innovations.com |    1962     |
             
I love to cook with wine.     Sometimes I even put it in the food.
Reply to
Jim Thompson

You didn't get him to bring VC money?

Reply to
krw

of

Summer of 1998, at least that's when it started.

--
Regards, Joerg

http://www.analogconsultants.com/

"gmail" domain blocked because of excessive spam.
Use another domain or send PM.
Reply to
Joerg

"Jim Thompson" wrote in message news: snipped-for-privacy@4ax.com...

Pretty old -- it's from 1998. See here:

formatting link

Reply to
Joel Koltner

Mine is newer, serial number C031494. Can't remember when I bought it... at Fry's (Phoenix). ...Jim Thompson

-- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at

formatting link
| 1962 | I love to cook with wine. Sometimes I even put it in the food.

Reply to
Jim Thompson

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.