EEVblog #512 - Rigol DP832 Bad Design Investigation

[madires]

I've got the points marked on the picture, 1 and 2 are the heat sink connections, 3 is the VAdj or pin 1 on the LM317, 4 is the Output or pin 2 on the LM317, 5 is the Input or pin 3 on the LM317, and 6 is a resistor point which I've seen some people connect to for different mods. I'm connecting In+ to point 5, In- to point 2, and Out+ to point 4.

I feel like an idiot as it seems many have had no issues with this but I'm looking for any advice on what i'm doing wrong here. I have my LM2596 adjusted to a 5.12V output but when I connect it in the power supply the output power at point 4, that is normally around 11V with the LM317, goes low to around 1V which renders the step down circuit useless.

Have you checked if point 2 (for mounting the heatsink) is connected to ground and not something else or even floating?

[mcinque]

My local dealer, BatterFly Italy, did NOT call me - like promised via email - for the RMA of my DP832. I was told that the return would be made on April.

Now it's almost June, and nothing happened. Even if this issue could be not directly in relation with BatterFly Italy (maybe it's Rigol Europe that is in fault), my dealer could at least inform me about the delay. Instead, I feel like I was abandoned. And probably is what I am. 

This issue, if not solved from BatterFly Italy, make me understand that it's better to buy other T&M instruments brands than Rigol. And probably not from BatterFly: their customer support is - at the moment - very disappointing. 

[Bomber18]

Have you checked if point 2 (for mounting the heatsink) is connected to ground and not something else or even floating?

I was able to probe those heatsink points last night and it does look like they are just floating.  My fault for making assumptions from the pictures posted and not checking myself. Thanks for the help!

[AndersAnd]

Have you checked if point 2 (for mounting the heatsink) is connected to ground and not something else or even floating?

I was able to probe those heatsink points last night and it does look like they are just floating.  My fault for making assumptions from the pictures posted and not checking myself. Thanks for the help!

The housing on LM317 is connected to Vout (pin 2), so connecting the LM317's heatsink to GND would mean shorting Vout to GND.
The housing on TO-220 devices are always connected to one of the three pins, and there's no GND pin on LM317 since it's adjustable. So obviously the heatsink pads are not connected to GND as this would require unnecessary electrical (and somewhat thermal) insulation between the LM317 and the heatsink.

On fixed positive voltage regulators like LM78xx however, pin 2 is a GND pin, and the housing is connected to pin 2 on these devices too. But on adjustable voltage regulators there's no GND. And for negative fixed voltage regulators like LM79xx the housing is still connected to pin 2, but to make it more confusing, the pins are swapped compared to LM78xx, so pin 2 and the housing is Vin, with GND on pin 1 and Vout on pin 3.

[stormbr]

As I wrote before ordered mine from Tequipment about a year ago. Came a few months later with all reported here defects. Teuipment wouldn't help with the defective unit, sent me to Rigol, fine. Waited a few moths, got a decent Hameg PSU for the same price (from the forum here) and asked Rigol to return the DP832A. They agreed, shipped it two months ago, and they disappeared. Not replying to my emails, phone line always busy, etc. Not even sure if Tequipment is supposed to return my money (they got it initially) or Rigol. Not really impressed by the customer service of either company. It's a clear case of defective product line, solve it among yourselves, and don't make your customers do your work. Blah, rant over...

Same problem here, Tequipment offers no guarantee about the problems with DP832. I'm fighting for six months and nothing happens.

And I thought this only happened in Brazil.

As they say here: is not easy for anyone.

[mcinque]

Same problem here, Tequipment offers no guarantee about the problems with DP832. I'm fighting for six months and nothing happens.

As alternative, we can put a magnetron over the digital board and turn it on for 1 second just to fry some opamps: with a dead unit the warranty must be applied with no excuses. 

[stormbr]

As alternative, we can put a magnetron over the digital board and turn it on for 1 second just to fry some opamps: with a dead unit the warranty must be applied with no excuses. 

I lost this fight with Rigol/Tequipment. 

The shipment cost is very expensive in my case, better i purchase other device.

Two months with my lab stoped.

Good luck for you too.

[Corporate666]

As I wrote before ordered mine from Tequipment about a year ago. Came a few months later with all reported here defects. Teuipment wouldn't help with the defective unit, sent me to Rigol, fine. Waited a few moths, got a decent Hameg PSU for the same price (from the forum here) and asked Rigol to return the DP832A. They agreed, shipped it two months ago, and they disappeared. Not replying to my emails, phone line always busy, etc. Not even sure if Tequipment is supposed to return my money (they got it initially) or Rigol. Not really impressed by the customer service of either company. It's a clear case of defective product line, solve it among yourselves, and don't make your customers do your work. Blah, rant over...

Same problem here, Tequipment offers no guarantee about the problems with DP832. I'm fighting for six months and nothing happens.

And I thought this only happened in Brazil.

As they say here: is not easy for anyone.

Didn't you hack your device?  (= Warranty void).  And Rigol sent you a replacement board due to the high cost of shipping to Brazil, right?

It is unfortunate that you are experiencing problems, but TEquipment has done nothing wrong, and Rigol has gone above and beyond for you on a unit that has no warranty because it was modified. 

Hacking equipment always runs the risk of bricking it or killing it in other ways.  When the potential negative outcome occurs, it's not the manufacturers fault, and certainly not the vendors fault to pay for shipping for manufacturer defects, whether hacked or not.

[tsmith35]

So, it appears that the Rigol 832 is a garbage power supply with a garbage warranty. Might as well buy something off of Aliexpress, save the money and take your chances. At least they don't mislead you into thinking you're buying a professionally-designed and supported piece of equipment.

[Bored@Work]

It is unfortunate that you are experiencing problems, but TEquipment has done nothing wrong

A supplier going into hiding is a problem. Interestingly, we are talking about a supplier who is known for having issues with non-US customers in general.

[ivaylo]

Not without trouble (took me months) but I managed to get my money back. The way it worked was Rigol issued a RMA and I sent them the unit. Then they send Tequipment some sort of notification and Tequipment issued the refund. It's been nothing but waiting with buying Rigol through Tequipment:
 - order at Tequipment, and wait 4 months to get what you paid for (serious)
 - while I waited the news spread that the DP832 is a lemon
 - finally got it and confirmed that mine had all reported problems
 - immediately raised it with Tequipment but they just forwarded me to Rigol's recall page
 - waited 3-4 months, Rigol ignored my emails so I started bugging Tequipment again
 - they put me in touch with Jason Chonko at Rigol, after a few weeks of correspondence he issued a RMA
 - sent them the unit immediately and waited patiently
 - fast forward 2 more months, reminded them they told me 'accounting is slow'
 - another another month, turned out Rigol notified Tequipment but they didn't know  what that refund was for
 - then finally a very pleasant woman at Tequipment made sure I got my refund
 - phew...

Pretty much a whole year from the moment I ordered it to the moment I got refunded. Glad I had the extra funds to just buy a Hameg from Top Loser here on the forum so I can do whatever I wanted to do with a PSU like that. Anyways, the lesson(s) - the fact that Agilent used to outsource with Rigol doesn't mean that Rigol is Agilent, and the fact Tequipment have something listed on the website doesn't mean that they have it in stock or that they'll support you in any meaningful way...

[stormbr]

Didn't you hack your device?  (= Warranty void).  And Rigol sent you a replacement board due to the high cost of shipping to Brazil, right?

It is unfortunate that you are experiencing problems, but TEquipment has done nothing wrong, and Rigol has gone above and beyond for you on a unit that has no warranty because it was modified. 

Hacking equipment always runs the risk of bricking it or killing it in other ways.  When the potential negative outcome occurs, it's not the manufacturers fault, and certainly not the vendors fault to pay for shipping for manufacturer defects, whether hacked or not.

Yes, was hacked, but i never was asked about this.

I installed the new digital board and lost two channels (2 and 3 - firmware 1.03), looks that happens only with me, but I'll pay for the shipping cost.

The Tequipment said that will send at most in two weeks other device, because are waiting for a new batch to arrive, but already it passarm two months.

I'll wait another 15 days and buy another device, if necessary.

Not without trouble (took me months) but I managed to get my money back. The way it worked was Rigol issued a RMA and I sent them the unit. Then they send Tequipment some sort of notification and Tequipment issued the refund. It's been nothing but waiting with buying Rigol through Tequipment:
 - order at Tequipment, and wait 4 months to get what you paid for (serious)
 - while I waited the news spread that the DP832 is a lemon
 - finally got it and confirmed that mine had all reported problems
 - immediately raised it with Tequipment but they just forwarded me to Rigol's recall page
 - waited 3-4 months, Rigol ignored my emails so I started bugging Tequipment again
 - they put me in touch with Jason Chonko at Rigol, after a few weeks of correspondence he issued a RMA
 - sent them the unit immediately and waited patiently
 - fast forward 2 more months, reminded them they told me 'accounting is slow'
 - another another month, turned out Rigol notified Tequipment but they didn't know  what that refund was for
 - then finally a very pleasant woman at Tequipment made sure I got my refund
 - phew...

Pretty much a whole year from the moment I ordered it to the moment I got refunded. Glad I had the extra funds to just buy a Hameg from Top Loser here on the forum so I can do whatever I wanted to do with a PSU like that. Anyways, the lesson(s) - the fact that Agilent used to outsource with Rigol doesn't mean that Rigol is Agilent, and the fact Tequipment have something listed on the website doesn't mean that they have it in stock or that they'll support you in any meaningful way...

I have 4 months with Rigol (Jason Chonko) and 2 months with Tequipment.

[Bomber18]

I've got the points marked on the picture, 1 and 2 are the heat sink connections, 3 is the VAdj or pin 1 on the LM317, 4 is the Output or pin 2 on the LM317, 5 is the Input or pin 3 on the LM317, and 6 is a resistor point which I've seen some people connect to for different mods. I'm connecting In+ to point 5, In- to point 2, and Out+ to point 4.

A follow up for anyone else doing the step down mod. I got mine working with In+ to point 5, In- to point 6, and Out+ to point 4.

As far as the Rigol/Tequipment discussion goes i'd be lying if I said I wasn't jaded by the whole incident. I decided to buy new equipment when I was putting together a lab partly for the warranty and to see what that's worth now I don't know if i'll put the same value in it as I once did atleast not for the Rigol name.

[Rasz]

As far as the Rigol/Tequipment discussion goes i'd be lying if I said I wasn't jaded

Just like in the case of rusting case of Siglent SDG5000 I actively discourage ANYONE who I hear is looking for new product to stay away from Rigol supply. I DONT CARE about excuses, or 3 shitty failed fix versions. There are no excuses for failing so hard.

So far I managed to steer two people clear of Rigol psu (actually one person and one repair shop). Not many people on the market for new  siggen in my circle of friends, but that doesnt stop me from mentioning effing RUST inside brand new equipment when we talk about shopping gear.

[mcinque]

Yeah, Rigol is making a very bad impression, I can't figure how a brand that effectively CAN produce good equipment could fail so miserably in helpdesk and in warranty. 

Their message to their customers is "Think twice before buying our products, because if you have some troubles with them, you'll be alone". And this could be only an epic fail strategy created by some meth/crack addicted sales manager. 

Honestly, I can't understand why they are so stupid. They are losing sales and, most of all, reputation for a so silly issue.

All Chinese products always lack something in some way, and this is not racism, it's a fact:   

[tsmith35]

Their message to their customers is "Think twice before buying our products, because if you have some troubles with them, you'll be alone". And this could be only an epic fail strategy created by some meth/crack addicted sales manager. 

It's "eBay" mentality: sold as-is. Perhaps they ran an eBay shop before they went big time.

[mcinque]

It's "eBay" mentality: sold as-is.

There's nothing wrong with that if you warn me before the purchase.
Knowing that that is your marketing policy, if I decide to buy, I'll take my risks.

But you CAN NOT declare "3 years warranty" and then do the exact opposite, forgetting the customers. F**k that. If I knew this s*it, I would have bought Siglent, Uni-T or Atten.

[jimjam]

It's a pity. Feature wise it seems good. I am looking for a Power supply right now. I guess I'll get a Siglent.

Dave mentioned in his blog that Siglent had far worse rust issues than Rigol but I can't find the video on him doing a siglent power supply review

[Corporate666]

It is unfortunate that you are experiencing problems, but TEquipment has done nothing wrong

A supplier going into hiding is a problem. Interestingly, we are talking about a supplier who is known for having issues with non-US customers in general.

TEquipment isn't hiding at all - you are believing one side of the story, and I am very sure TEquipment has a very different view, that they won't be posting here because there are plenty of bored people waiting to pounce on them for being fatcats taking advantage of engineers.

I bought all my Rigol stuff from TE.  When the DP832 issue came to light, I contacted Rigol with no luck (by email).  I then contacted TE - months after I bought the unit and my return window was up (and TE's responsibility to me was ended), and they got in touch with Rigol and made sure I was taken care of.

The "issues with non US customers" is a bullshit criticism.  They have well defined payment processes that people complain about... well, don't buy from them then.  The fact is that people are like kids - they want their cake and to eat it too.   They don't want to buy locally because local suppliers are more expensive, but they don't want to take on any additional work to buy overseas.  In this case, why should TE pay $170 to ship back a unit from Brazil?  They shouldn't.  Frankly, Rigol shouldn't either... shipping costs are consequential damages and every company is going to disclaim consequential damages.  I hear that shit all the time from customers... will Sony pay your catering bill because the big screen TV you bought for your superbowl party died in the first quarter?  Will Chevy pay the bills for your missed holiday because your car wouldn't start and you missed your flight to Europe?  Of course not.  That's just the risk you take buying internationally... the reward is you save money, if things work out.  If people don't want to take on that risk, then buying a brand new design of a product isn't the best idea.  Not to mention, it's not like the PSU's were non-functional.  They were running at a temperature most engineers would agree was too high - it's not like they were bricks.

[stormbr]

TE and Rigol is a good store and nothing more, but six months to solve this problem is a very bad situation.

My inbox was updated today with a email of UPS@29Lbs.

Thanks god !   

[mcinque]

Not to mention, it's not like the PSU's were non-functional.  They were running at a temperature most engineers would agree was too high - it's not like they were bricks.

Sure. So now the problem doesn't even exist! Who cares about the catastrophic failure to the digital board that that regulator will cause when it will blow like a firework in the next 2 years?

I've not paid for a time bomb.I've paid for a PSU that should last for some years.

[Rasz]

Not to mention, it's not like the PSU's were non-functional.

yes, psu didnt reset or anything , right?

[mcinque]

In this case, why should TE pay $170 to ship back a unit from Brazil?  They shouldn't.

If any company won't/can't manage international issues, why the hell they choose to sell internationally? Oh, yes... maybe because profit. We're all great merchants when all goes fine. It's when you must manage troubles that you show your company reliability.

You don't want the international customers to bother you? Stop selling internationally. Period.

shipping costs are consequential damages

Probably in your country. Not in EU for a thing like this one (bad engineering).

will Sony pay your catering bill because the big screen TV you bought for your superbowl party died in the first quarter?

These are of course examples of "consequential damages", even if they are bizarre (I would have choose "burnt or damaged circuits powered to the PSU, profit loss etcetera). No sane person would ask to the manufacturer to pay the catering bill if the TV died during supebowl. Seriously.

[Corporate666]

Sure. So now the problem doesn't even exist! Who cares about the catastrophic failure to the digital board that that regulator will cause when it will blow like a firework in the next 2 years?

I've not paid for a time bomb.I've paid for a PSU that should last for some years.

Come on - I'm laughing here.  So now you've determined the whole logic board will fail within 2 years based on.... what exactly?  I am not aware of any failures - are you?  And... Rigol offered to fix the problem.  I think some folks are only happy when they're unhappy.

Shit happens.  And when it does, you hope the perpetrator of that shit fixes it.  In this case, that's exactly what happened.

[Corporate666]

Not to mention, it's not like the PSU's were non-functional.

yes, psu didnt reset or anything , right?

Did they reset?  I believe Dave got his to reset with the case off (= no airflow).  When I talked to the guys at Rigol, they were well aware of Dave's video, but not aware of any 832's which were actually resetting in normal use.  I tried to get mine to reset, but it didn't.  As I said, some folks are blowing this way out of proportion (look at the above post about exploding regulators within 2 years causing catastrophic damage).  Fact is, there was a part running too hot, so they fixed it.  Next.