Author Topic: Rigol DP832 - smoked channel 1 [FIXED]  (Read 25817 times)

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Offline SkimaskTopic starter

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Rigol DP832 - smoked channel 1 [FIXED]
« on: December 20, 2014, 03:40:11 am »
Pulled a dumb-ass move this afternoon.  Needed to top off a 12v Pb batt.  Plugged it in backwards.  Got some nice sparks at the alligator clips and that wonderful odor of smoke escaping from somewhere inside the '832.
Don't have time to pull it apart for at least a few days.
Who's got the schematics and/or a good idea what part I have to try and put smoke back into?
« Last Edit: January 04, 2015, 10:56:06 pm by Skimask »
I didn't take it apart.
I turned it on.

The only stupid question is, well, most of them...

Save a fuse...Blow an electrician.
 

Offline c4757p

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Re: Rigol DP832 - smoked channel 1
« Reply #1 on: December 20, 2014, 03:47:49 am »
Probably, a chunky diode whose entire purpose is to sacrifice itself to protect the rest of the PSU. Should be easy.
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Offline robrenz

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Re: Rigol DP832 - smoked channel 1
« Reply #2 on: December 20, 2014, 03:49:34 am »
Dang... the one time I have a clue and you beat me to it :)

Offline SkimaskTopic starter

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Re: Rigol DP832 - smoked channel 1
« Reply #3 on: December 20, 2014, 04:32:15 am »
Odd...doesn't smell like a diode  :-DD

I'll try to make a cheesy video of the repair when I get to it.
I can't possibly be the only one that has invented such stupidity...or could I?
I didn't take it apart.
I turned it on.

The only stupid question is, well, most of them...

Save a fuse...Blow an electrician.
 

Offline bronson

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Re: Rigol DP832 - smoked channel 1
« Reply #4 on: December 20, 2014, 10:15:05 pm »
Given how the 832 puts positive on the left, I'd guess you're far from the only person who's done that.
 

Offline Howardlong

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Re: Rigol DP832 - smoked channel 1
« Reply #5 on: December 20, 2014, 10:26:22 pm »
Given how the 832 puts positive on the left, I'd guess you're far from the only person who's done that.

Absolutely, not the smartest design decision ever made that's for sure. The first time I used the DP832 I operated it the wrong way around despite the red and black leads I use. Luckily I usually put in series Schottkies pre regulators as a matter of course on my breadboarded stuff to save me from myself, clearly it worked.
 

Offline jadew

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Re: Rigol DP832 - smoked channel 1
« Reply #6 on: December 20, 2014, 10:38:24 pm »
Given how the 832 puts positive on the left, I'd guess you're far from the only person who's done that.

Absolutely, not the smartest design decision ever made that's for sure. The first time I used the DP832 I operated it the wrong way around despite the red and black leads I use. Luckily I usually put in series Schottkies pre regulators as a matter of course on my breadboarded stuff to save me from myself, clearly it worked.

I'm not sure what supplies you guys have been using, but I think that's the standard. I have two power supplies from different manufacturers on my bench, both with the positive on the left. Agilent has them like that too, which would probably account for the majority of lab power supplies.

So... what brands have them the other way around?
 

Offline Circuitous

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Re: Rigol DP832 - smoked channel 1
« Reply #7 on: December 21, 2014, 12:38:39 am »
All of my power supplies, from 5 different manufacturers (Keithley, Rigol, Array, Maynuo...) are all Positive on the left, same with the DMMs and electronic loads.


Offline tautech

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Re: Rigol DP832 - smoked channel 1
« Reply #8 on: December 21, 2014, 01:06:30 am »
All of my power supplies, from 5 different manufacturers (Keithley, Rigol, Array, Maynuo...) are all Positive on the left, same with the DMMs and electronic loads.
Interesting  :-// seems counter-intuitive to a right-handed person and certainly not what I have used or am used to.
Must just be the Asian stuff I have here.
Fluke 15B
Vichy VC99
SDM3055 Bench DMM
MCH PSU's

All positive on right
Siglent PSU's also.

I wonder where this apparent LH positive standard originated from and how far back it goes?
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Offline Nerull

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Re: Rigol DP832 - smoked channel 1
« Reply #9 on: December 21, 2014, 02:23:00 am »
I don't know about other companies, but HP started in 1958. Their PSUs of the era used a three-connector triangle configuration, which generally was setup with the positive and negative outputs oriented vertically, and the ground beside them, like this, from 1955:



In 1958 they rotated it, with positive on the left.



By the mid 60s they looked like something you might see on a PSU today:

 

Offline jadew

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Re: Rigol DP832 - smoked channel 1
« Reply #10 on: December 21, 2014, 02:36:33 am »
Personally, I used positive, negative and ground (from left to right) on my home made PSUs and that's before I even saw a professional PSU.

I remember I gave this some thought and it felt like the right way of doing it, so there might be more to it.
 

Offline c4757p

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Re: Rigol DP832 - smoked channel 1
« Reply #11 on: December 21, 2014, 02:52:21 am »
Personally, I used positive, negative and ground (from left to right) on my home made PSUs and that's before I even saw a professional PSU.

I remember I gave this some thought and it felt like the right way of doing it, so there might be more to it.

IMO, there should be a direct line from ground to both of the output terminals, so that you can ground either one with a short bar.
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Offline jadew

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Re: Rigol DP832 - smoked channel 1
« Reply #12 on: December 21, 2014, 03:04:28 am »
Personally, I used positive, negative and ground (from left to right) on my home made PSUs and that's before I even saw a professional PSU.

I remember I gave this some thought and it felt like the right way of doing it, so there might be more to it.

IMO, there should be a direct line from ground to both of the output terminals, so that you can ground either one with a short bar.


Yeah, I don't really like the ones with the ground in the middle. Can't put my finger on it, but I think the benefit is too small to have to deal with that annoyance all the time. It just feels like it's in the way.

I never ground the positive terminal anyway, if anything I tie it to the negative terminal of a different supply, which may or may not be grounded - makes a lot more sense to me. If there was a situation where I would use it as a negative supply by itself, I wouldn't mind using a longer piece of wire, if that meant that I can keep the ground lead out of my way the rest of the time :)
 

Offline c4757p

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Re: Rigol DP832 - smoked channel 1
« Reply #13 on: December 21, 2014, 03:05:57 am »
I adore the early HP triangular configuration. We need to bring that back.
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Offline jadew

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Re: Rigol DP832 - smoked channel 1
« Reply #14 on: December 21, 2014, 03:06:59 am »
I adore the early HP triangular configuration. We need to bring that back.

I agree, no compromise!
 

Offline tautech

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Re: Rigol DP832 - smoked channel 1
« Reply #15 on: December 21, 2014, 04:40:12 am »
I adore the early HP triangular configuration. We need to bring that back.
Yes it is smart.
Does it need a different colour scheme?
Red   Black
   Green
And in a binding post configuration of course.  :-+
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Offline ivan747

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Re: Rigol DP832 - smoked channel 1
« Reply #16 on: December 21, 2014, 10:18:39 pm »
By coincidence I was meditating on this exact topic just before visiting the forum, and in fact, I came to the same conclusion that the early 50's HP triangle is the best solution. It's the most intuitive, has positive and negative just as you will find it on an schematic (positive is the uppermost, negative is on the bottom), it has 3/4" spacing between all connectors, you can use 3/4" spaced dual banana plugs as well. Binding posts accept bare wires, U terminals, banana plugs, alligator clips, clips, short bars, actual bananas...
« Last Edit: December 21, 2014, 10:21:01 pm by ivan747 »
 

Offline ivan747

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Re: Rigol DP832 - smoked channel 1
« Reply #17 on: December 21, 2014, 11:27:50 pm »
We kinda derailed the thread  :-\

Have you opened the power supply yet, OP? Show us photos of the board, there should be visible damage it the thing smelled like you said.
 

Offline SkimaskTopic starter

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Re: Rigol DP832 - smoked channel 1
« Reply #18 on: December 22, 2014, 05:51:03 am »
Working on cleaning up the shop, first time all year and it's a pit.  I got a bench cleared.  Gonna work on it in a bit.
Don't expect much though.
I didn't take it apart.
I turned it on.

The only stupid question is, well, most of them...

Save a fuse...Blow an electrician.
 

Offline SkimaskTopic starter

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Re: Rigol DP832 - smoked channel 1
« Reply #19 on: December 22, 2014, 07:46:50 am »
https://www.youtube.com/watch?v=f2hQiE-G_f8&feature=youtu.be

Found R52 on the top board smoked.  Current sense resistor for channel 1.  Think it's a .020 ohm, 3W, 2512 (or is that 1225?) sideways mounted SMT resistor.

http://www.digikey.com/product-detail/en/RL3720WT-R020-F/RL37WT.02FCT-ND/567370

http://www.mouser.com/Search/Refine.aspx?Keyword=66-LRF2512-LF-R020-F

May as well buy a small bundle of them, if they're the right type.

The trace on the PCB is broken/burnt, but just barely.
A chunk of wire, some scraping on the coating, solder it up, coat it with a bit of epoxy...Good as new!

I'll make a better repair video after I get the parts, and maybe a better camera that'll focus up close a fair amount better.

Note:  Uploaded the wrong video.  The right video is cut up a bit, captioned, etc.  Will handle it later.
« Last Edit: December 22, 2014, 07:57:40 am by Skimask »
I didn't take it apart.
I turned it on.

The only stupid question is, well, most of them...

Save a fuse...Blow an electrician.
 

Offline SkimaskTopic starter

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Re: Rigol DP832 - smoked channel 1
« Reply #20 on: December 27, 2014, 09:46:57 pm »
The two links above aren't even close to correct.  They're for the sideways type SMT resistors...mount the long way rather than the short way.  "Wide" type packages.

This is the closest thing I could find at Digikey
WSL2816R0200FEH
.02 ohms, 2 watts, 75ppm, 2816 package.
I measured the original at about 7.4mm x 4.2mm.  This package is 7.1mm x 4.2mm.

Thinking since I'm swapping out 1 of the 3 channels current sense resistor, I should probably swap out all 3 while I'm in there...to make all 3 the same.
What say the masses?
Also going to buy a bunch of them.  Maybe I can hook up somebody else in the future...
I didn't take it apart.
I turned it on.

The only stupid question is, well, most of them...

Save a fuse...Blow an electrician.
 

Offline ivan747

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Re: Rigol DP832 - smoked channel 1
« Reply #21 on: December 29, 2014, 01:20:17 am »
The two links above aren't even close to correct.  They're for the sideways type SMT resistors...mount the long way rather than the short way.  "Wide" type packages.

This is the closest thing I could find at Digikey
WSL2816R0200FEH
.02 ohms, 2 watts, 75ppm, 2816 package.
I measured the original at about 7.4mm x 4.2mm.  This package is 7.1mm x 4.2mm.

Thinking since I'm swapping out 1 of the 3 channels current sense resistor, I should probably swap out all 3 while I'm in there...to make all 3 the same.
What say the masses?
Also going to buy a bunch of them.  Maybe I can hook up somebody else in the future...

I think you should leave the other channels intact. That way you have 2 pristine channels as references if the CH1 fix turns wrong.

But, yes, order about 4 of those so that the Digi-Key guy who that 1 resistor from the top shelf of the bottom of the storage room doesn't go suicidal  ::)
 

Offline Macbeth

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Re: Rigol DP832 - smoked channel 1
« Reply #22 on: December 29, 2014, 01:34:12 am »
Blimey, I wouldn't have thought a polarity reversal during a battery charge could do that to a DP832. It's my second favourite PSU.

Thankfully I use my 6632B as a battery charger and it works a treat no matter what scummy cells you chuck at it. There is something to love about that old VFD beast.
 

Offline SkimaskTopic starter

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Re: Rigol DP832 - smoked channel 1
« Reply #23 on: December 29, 2014, 03:07:13 am »
@ivan - Good thought...about leaving channel 2&3 alone.  And I ordered 20 of them.  Not that I plan on smoking more channels or anything.

@Macbeth - I would've thought the same thing.  Maybe there's a DP832 "reverse polarity input protection mod" in there somewhere.
And, yes, I should've walked the 50 feet over to the garage and grabbed my small battery charger to top off the battery, but, that was over there...and the DP832 was already right in front of me :)
I didn't take it apart.
I turned it on.

The only stupid question is, well, most of them...

Save a fuse...Blow an electrician.
 

Offline Nerull

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Re: Rigol DP832 - smoked channel 1
« Reply #24 on: December 29, 2014, 04:05:15 am »
Blimey, I wouldn't have thought a polarity reversal during a battery charge could do that to a DP832. It's my second favourite PSU.

Thankfully I use my 6632B as a battery charger and it works a treat no matter what scummy cells you chuck at it. There is something to love about that old VFD beast.

Most lab PSUs - including the 6632B, do not support negative voltages across the output terminals. Bad Things can and will happen. HP recommends putting a diode in the circuit when charging batteries to prevent the crowbar circuit from blowing the internals out of the PSU - it shorts the output terminals together, through the PCB. Also be careful about never turning the supply on or off with a battery connected.
« Last Edit: December 29, 2014, 04:09:15 am by Nerull »
 


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