Author Topic: What's this please? (Component Advice)  (Read 583803 times)

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Offline Srbel

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Re: What's this please? (Component Advice)
« Reply #1050 on: September 28, 2016, 05:36:28 am »
What brand of caps are these?

 

Offline helius

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Offline Srbel

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Re: What's this please? (Component Advice)
« Reply #1052 on: September 28, 2016, 12:12:48 pm »
Thank you!

Are they good quality? Not as good as Japanese brands, obviously, but should be a lot better than Chinese ones?
 

Offline gildasd

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Re: What's this please? (Component Advice)
« Reply #1053 on: September 29, 2016, 06:16:20 pm »
Thank you!

Are they good quality? Not as good as Japanese brands, obviously, but should be a lot better than Chinese ones?
Mistreated very badly a bunch of secondhand examples and they survived, so if you use them within spec, you should be fine.
I'm electronically illiterate
 
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Offline MasterTech

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Re: What's this please? (Component Advice)
« Reply #1054 on: September 29, 2016, 06:27:29 pm »
From an LED driver... I have a hard time finding info on it. Can anyone point me in the right direction?
The code reads "IAFSF".

Thanx...

Check if that could be a LM3880-1AF


 

Offline jitter

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Re: What's this please? (Component Advice)
« Reply #1055 on: September 30, 2016, 04:38:25 am »
From an LED driver... I have a hard time finding info on it. Can anyone point me in the right direction?
The code reads "IAFSF".

Thanx...

Check if that could be a LM3880-1AF

Thanks for coming back to this.
Marco noticed the first symbol in the code actually wasn't an "I" or a "1" but just a vertical line (|). It turned out to be most likely a MP4026.
 

Offline FrankBuss

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Re: What's this please? (Component Advice)
« Reply #1056 on: October 01, 2016, 08:54:51 pm »
What's this?



6 of it are soldered on a DYS XM20A (ESC, brushless motor controller, 20 A), 4 mm edge length. I guess it is a FET, but I can't find the datasheet for it.
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Offline Andy Watson

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Offline gamalot

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Re: What's this please? (Component Advice)
« Reply #1058 on: October 01, 2016, 09:23:06 pm »
What's this?



6 of it are soldered on a DYS XM20A (ESC, brushless motor controller, 20 A), 4 mm edge length. I guess it is a FET, but I can't find the datasheet for it.

Alpha & Omega AON7418

http://aosmd.com/res/data_sheets/AON7418.pdf
 

Offline FrankBuss

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Re: What's this please? (Component Advice)
« Reply #1059 on: October 01, 2016, 09:24:24 pm »
Thanks!
So Long, and Thanks for All the Fish
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Offline FrankBuss

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Re: What's this please? (Component Advice)
« Reply #1060 on: October 02, 2016, 03:37:24 pm »
Ok, I have another one:



On the same DYS XM20A ESC. I guess some kind of FET driver. 3 of it are driving 6 FETs.
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Offline gamalot

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Re: What's this please? (Component Advice)
« Reply #1061 on: October 02, 2016, 04:52:29 pm »
Ok, I have another one:



On the same DYS XM20A ESC. I guess some kind of FET driver. 3 of it are driving 6 FETs.

Not MCP3201, not THS3201, not ADuM3201, maybe LPD3201  :)

http://file1.dzsc.com/product/14/06/12/1014430_145049441.pdf
 

Offline FrankBuss

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Re: What's this please? (Component Advice)
« Reply #1062 on: October 02, 2016, 05:09:12 pm »
Not MCP3201, not THS3201, not ADuM3201, maybe LPD3201  :)

http://file1.dzsc.com/product/14/06/12/1014430_145049441.pdf
This doesn't looks right, it is not a voltage regulator and I guess one IC will have 2 buffers to drive 2 FETs.
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Offline gamalot

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Re: What's this please? (Component Advice)
« Reply #1063 on: October 02, 2016, 05:31:00 pm »
Not MCP3201, not THS3201, not ADuM3201, maybe LPD3201  :)

http://file1.dzsc.com/product/14/06/12/1014430_145049441.pdf
This doesn't looks right, it is not a voltage regulator and I guess one IC will have 2 buffers to drive 2 FETs.

Try QM3201 or UM3201

http://www.1mos.com/upload/file/UBIQ/QM3201S.pdf

http://www.wggk.net/upload/product/file/UM3201.pdf
 

Offline FrankBuss

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Re: What's this please? (Component Advice)
« Reply #1064 on: October 02, 2016, 06:28:56 pm »
This looks better, but the pinout is wrong. Pins 2 and 3 is gate (or buffer input, directly connected to the microcontroller, all gates with a 10k pulldown to GND), all pin 4 are connected to GND, all pin 1 are connected to the output of a 78L12 (this means using it with 3S LiPos might be a bit of a stretch, and definitely not a good idea to use it with 2S). Bit difficult to trace the other side because it goes to the back of the PCB.
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Offline gamalot

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Re: What's this please? (Component Advice)
« Reply #1065 on: October 02, 2016, 06:55:22 pm »
This looks better, but the pinout is wrong. Pins 2 and 3 is gate (or buffer input, directly connected to the microcontroller, all gates with a 10k pulldown to GND), all pin 4 are connected to GND, all pin 1 are connected to the output of a 78L12 (this means using it with 3S LiPos might be a bit of a stretch, and definitely not a good idea to use it with 2S). Bit difficult to trace the other side because it goes to the back of the PCB.

OK, hope this time is right IMP3201  :)

http://www.ds-imp.com.cn/pdf/IMP3201.pdf
 

Offline FrankBuss

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Re: What's this please? (Component Advice)
« Reply #1066 on: October 02, 2016, 08:14:29 pm »
OK, hope this time is right IMP3201  :)

http://www.ds-imp.com.cn/pdf/IMP3201.pdf

Yes, this looks right, I can even measure the 0.5 V voltage drop of the diode and I can see the capacitors, thanks!  :)

Interesting chip. I don't understand C2. Is it kind of bootstrapping with the outputs of the FET for higher gate voltage, and with the diode initially using the 12 V supply? Looks tricky. And Google translate says for the Vcc pin 1 "Low side logic fixed power supply", but maximum rating says up to 25 V, so I guess this is ok.

Looks like there is even a shop in Shenzen where I can buy it:

http://www.jotrin.com/product/parts/IMP3201ESA_T

Too bad it is not listed in findchips.com or at Digikey.

Next up: an European company clones a Chinese ESC :-)
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Offline STMartin

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Re: What's this please? (Component Advice)
« Reply #1067 on: November 10, 2016, 04:09:42 am »
I'm repairing an Agilent E3646A that had a bad diode for the -15V bias supply. The case mark is C1J and I'm not sure exactly what it is.

Here's a portion of the schematic:



It's component CR140.

Given the application and a google search, I believe it's a zener diode; although I've never seen that symbol used for it before. Is this right?

Also, the schematic has it marked as 5.6, which I assume means 5.6 V. However, since the purpose is to get -15 V from a -17.4 V rail, shouldn't it be a 2.4 V?

I soldered in a 2.4 V through-hole zener and measured the current at about 68 mA under full load. Could I just get any 'ol zener of the proper voltage and current capacity and slap it in there?
« Last Edit: November 10, 2016, 04:15:05 am by STMartin »
 

Offline madires

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Re: What's this please? (Component Advice)
« Reply #1068 on: November 10, 2016, 11:28:30 am »
Given the application and a google search, I believe it's a zener diode; although I've never seen that symbol used for it before. Is this right?

Yes, it's a Zener. That symbol is used in the EU.

Also, the schematic has it marked as 5.6, which I assume means 5.6 V. However, since the purpose is to get -15 V from a -17.4 V rail, shouldn't it be a 2.4 V?

The diagram shows only a tiny part of the power supply circuit, so I can't say anything about that. Maybe someone else can provide an educated guess.
 

Offline salbayeng

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Re: What's this please? (Component Advice)
« Reply #1069 on: November 10, 2016, 01:36:10 pm »
Looking at the schematic the zener diodes are not to convert 17.4 to 15v. , That will be done by a LM7815 or LM7915 regulator (TO220, on a heatsink).
The zeners are there to ensure the voltage at power off across the regulator isn't excessive. Not sure why they use zeners, a normal diode would be sufficient.
If you are driving a load that goes between +15v andv -15 rails (like Opamps), it is possible that one regulator might shutdown during startup if it's output gets dragged past gnd the wrong way, the zeners might help getting the 15v rails up to ~ 12v so they start properly.

The C1J might just be a normal 1N4004 type diode , there are many simple diode numbers like S1J ,  G1J , where the "1" is 1Amp, and the "J" is 600v.

 

Offline vk6zgo

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Re: What's this please? (Component Advice)
« Reply #1070 on: November 11, 2016, 12:38:56 am »
HP/Agilent are fond of that symbol for zeners--I've seen it on quite a few of their schematics.

If you look at your circuit diagram ,you will notice that the part of the +15v circuit shown is exactly the same as that for -15v,except that it has the zener the other way round.( another thing they like to do)

CR140 & CR139 are the same part number,so if the positive 15v supply still works,all the voltages around the
1902-1698 (CR139) will be the same value,(but inverted in polarity) as the -15v one.

 

Offline STMartin

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Re: What's this please? (Component Advice)
« Reply #1071 on: November 11, 2016, 01:46:06 am »
Awesome, thanks for the information everyone.  :-+

I looked through the rest of the schematics, and found regulators for 15V rails, but they're marked as +15V2 and -15V2, rather than +15V1 and -15V1, which is what is connected to the zeners. Here's that circuit:



I buzzed it out to be sure, and it doesn't appear to be the same 15V rail connected to the zeners. I'd kinda like to know if salbayeng is right about the zeners protecting the regulators/helping them start, or if they're meant to provide a voltage rail (or both?). Here's the rest of the bias supply circuit:



If this is the wrong thread to ask that, then I apologize, and you can disregard.

In any case, I guess it's somewhat beside the point. I'll see if the 2.4 V zeners I've got in there are within Agilent's specs, then whack in a 5.6 V and see if that's better or worse. At least now I know I need a 1 amp zener.

Thanks again!

EDIT: I borked it and shorted the diodes together, because I'm good at what I do. :-BROKE Also managed to lift a trace in the process.  :palm: Going in for emergency surgery. Guess I won't be selling this one.

EDIT2: Voltage regulators on the main board check out OK. No display with two beeps means it can't communicate with the display board. Probably blew a regulator local to the display or PC board. Will test those and try to hot glue the lifted trace down to prevent any further damage.
« Last Edit: November 12, 2016, 10:44:50 am by STMartin »
 

Offline madires

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Re: What's this please? (Component Advice)
« Reply #1072 on: November 11, 2016, 12:09:32 pm »
I'd suggest to move that to the "Repair" section. For a 2-channel lab PSU I'd expect isolated power sections for each channel, hence the !5V1 and 15V2 (also PCOM1 and PCOM2).
 

Offline salbayeng

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Re: What's this please? (Component Advice)
« Reply #1073 on: November 12, 2016, 08:49:57 am »
I'm with @maderes ,  probably two independent supplies.  (Or with power supplies sometimes the common of the floating power suppy rides with the positive terminal)
Pcom1 and pcom2 are dead giveaways.

Looking at the whole circuit now, my guess as to the role of the zener diodes is probably partly wrong.
CR139 is certainly a 5.6v zener, its probably biasing some transistors somewhere else, but with about 1mA , the voltage across it will be ~ 5v still nothing like 2.4v   
Maybe the 15V1 supplies get power fed from somewhere else most of the time? 
I'm guessing the +/-15V1 supplies are used by an opamp, and it doesn't care whether it gets 12v or 15v supply.
 

Offline salbayeng

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Re: What's this please? (Component Advice)
« Reply #1074 on: November 12, 2016, 08:59:02 am »
On closer inspection , the 15V1 supplies drive two opamps on this schematic  :palm: U124,U134
And note the clever use of U133  pretending to be a depletion mode MOSFET.
Given this supply works the fan, it probably also powers other non critical circuitry, so it should be eminently fixable.
 


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