Siglent spd3303x-e reboot problem - Page 1
Forum section: electronics / repair

author: qpit3a
author_rank: Contributor
timestamp: May 27, 2023, 12:03:42 pm
content: About a week ago my spd3303x-e started to get the problem where it re-boots (every 5 minutes or so - in the garage just before where it was very cold I think maybe 15 minutes. I looked on the forum and found that one suspect is the overheating bridge rectifier. I looked inside tonight and see that my device must be an updated unit as there's a heatsink on the bridge. I started measuring some temperaturs and the bridge gets to about 30 but there's a couple of diodes that get to 40. (measuring with a fairly cheap infra-red thermometer so not sure how accurate). My question is has anyone found that these diodes overheat and cause the same issue? Is 30 - 40 degrees C too hot? Just looked at datasheet for 1a diodes and this is not hot. Then again the cool parts of the board were about 10 degrees C.Yeah I just checked and these temperatures aren't high. Will need to check in another way as I don't trust how I measured. Wondering if anyone else has found a cause for this re-boot problem.I think I may have found an answerhttps://www.youtube.com/watch?v=2uhE6i6VGSs.Apparently another person has a unit with the new heatsink and still gets the issue as I am.Thanks for any help

author: qpit3a
author_rank: Contributor
timestamp: May 28, 2023, 02:24:49 am
content: Ok yeah if I put small fan on the area where the bridge rectifier is then no reboot so the issue is in the part of the board. It's also when the outputs are on as then that part is powering some relay coils. As per YouTube video I linked.

author: qpit3a
author_rank: Contributor
timestamp: May 28, 2023, 07:03:06 am
content: There Siglent, fixed it for you (I hope)...

author: tautech
author_rank: Super Contributor
timestamp: May 30, 2023, 09:52:32 am
content: Quote from: qpit3a on May 28, 2023, 07:03:06 amSorry late to the party and yes that will fix it.I've only seen the one do this continual reboot, a unit just a few days old that we immediately replaced.It's the small circular diode bridge failure < replace it = fixed.For years they used these little circular bridges and seem to not have given any trouble until recently however now I believe a HW mod has upgraded to a better bridge from one of these little critters.Liking the chunky replacement you did.Others that find this, within 3 years of purchase it's a warranty issue.

author: qpit3a
author_rank: Contributor
timestamp: May 30, 2023, 12:06:13 pm
content: I gave up on the warranty - the Australian distributor I bought from weren't interested in me I think - not a corporate customer. In any case I had the bits on hand so easy to fix. Am a little worried that the caps have cooked a bit and they're going to have reduced life. Was going to use a 25 Amp bridge but ddidn't think it would fit... Sort of like that's not a bridge this is a bridge...

author: qpit3a
author_rank: Contributor
timestamp: May 30, 2023, 09:55:30 pm
content: Also mine had a heatsink on same tiny bridge so if that's the new fix then doesn't work too well after about 2 yrs light use.

author: tautech
author_rank: Super Contributor
timestamp: May 30, 2023, 11:13:50 pm
content: Quote from: qpit3a on May 30, 2023, 09:55:30 pmNot seen any with heatsinks however replacement bridges Siglent sent us and a warranty replacement PCB are of an inline bridge design with a higher current bridge.The failure we had, one diode in the bridge had gone open and the resultant ripple set the unit into constant reboot mode.Maybe Siglent used a different circular bridge than original for whatever reason and it's just not up to the task.

author: qpit3a
author_rank: Contributor
timestamp: May 30, 2023, 11:18:57 pm
content: Ok thanks didn't check the old bridge so will be interesting to see if same open diode issue.

author: Faranight
author_rank: Unknown
timestamp: June 17, 2023, 03:42:10 pm
content: Damn! Looks like I got a free ticket to join this club as I've just been hit with the very same issue.I was trying to do some AVR programming while the unit suddenly rebooted a few times and then started turning off and back on again.I've had my SPD3303X for a few years, but used it very rarely. Searching on the internet, it seems to be a known problem.Tautech, I heard you mentioning in another thread that Siglent started replacing these bridges with more powerful versions that are placed off-board.Do you perhaps have the part number? Or qpit3a, do you have a part number of that bridge you showed in the pics?Thanks.

author: tautech
author_rank: Super Contributor
timestamp: June 17, 2023, 07:51:34 pm
content: Quote from: Faranight on June 17, 2023, 03:42:10 pmOnly member qpit3a's fix is the only one I know of that is done off the PCB.Siglents suggested fix is a bodge by having an inline bridge shoehorned into a circular bridge footprint.I suspect they reworked the PCB in later HW revisions to take an inline bridge as there's not much room to work with in the older PCB layout.TBH I'd make a small birds nest with 4 diodes and run a sleeved + and - back into the existing pads or go with qpit3a's fix with a remotely mounted bridge or maybe try to get one of these little 3A jobbies slotted into the existing footprint:https://www.retroamplis.com/BR305/enThe application is not very demanding as I believe the original bridge was only 2A rated.

author: qpit3a
author_rank: Contributor
timestamp: June 17, 2023, 10:46:06 pm
content: The original bridge is a 2W10 - 2A. My new bridge is something I had around and is BR106 10Amp.The original 2W10 failed even with a (tiny, and from factory) heatsink in my case. I also tried a small fan on that part of the board and that did fix the issue, but I didn't like that solution.

author: Faranight
author_rank: Unknown
timestamp: June 18, 2023, 05:52:31 am
content: Thanks for the info.I wonder... I've been googling this issue now, and I came across this video on Youtube where the guy does the diode bridge repair, but also includes certain 78xx linear regulators in the fix. He says that those were also getting too hot, so he decides to replace them with bigger ones (78L05 TO-92with7805 TO-220) and move some of them off-board to mount them on the chassis for better cooling. I found some IR shots of the PCB with the diode bridge overheating inthis thread, but I couldn't find any similar pictures for the said regulators. Do you have any info on this i.e. do the regulators really need replacing too?

author: qpit3a
author_rank: Contributor
timestamp: June 18, 2023, 06:51:20 am
content: I don't know about the regulators, pretty sure finger checked temps and seemed ok. I didn't find above video although I've seen another where put bridge out on long legs. This guy replaced capacitors which I am thinking I should have done. In this same videothere is an analysis suggesting main current draw is to the output relays and is after bridge but before the regulators - I was trusting this analysis (except I should have been less impatient perhaps and got some new caps).I made video too but didn't film much of the actual process of doing the repair. Just showed checking that problem is heat in that area with the fan and final result. I ran the PSU all night after and was ok and has been good since. Don't have flir so can't properly check temps. Used a infra red thermometer but that didn't show any temps more than ~40.. so I am suspicious wasn't getting good readings.

author: Faranight
author_rank: Unknown
timestamp: July 25, 2023, 05:43:17 pm
content: Hey, I know it's been a while, but here's my fix. Seems to be working fine without any reboots, and the new bridge barely gets hot.Although, the two linear regulators near the removed bridge still get pretty hot. Maybe I should have placed them off-board too?

author: mawyatt
author_rank: Super Contributor
timestamp: September 06, 2023, 04:05:33 pm
content: Quote from: tautech on June 17, 2023, 07:51:34 pmRob,Did Siglent ever have an official "fix" for this? One of our 3 units just began to hiccup a bit, and considering fixing it before we have to use it again.Best

author: tautech
author_rank: Super Contributor
timestamp: September 06, 2023, 08:43:05 pm
content: Quote from: mawyatt on September 06, 2023, 04:05:33 pmThere is warranty.They are not a complex/difficult repair but IMO qpit3a's fix above with an uprated bridge is the easiest if replacing the small circular bridge. Run a red/black pair and an AC pair off the PCB and mount the replacement bridge wherever is most convenient.There has been a HW change however exactly what has been changed has not been shared.No doubt the bridge has been uprated/changed so to be more reliable and another display feature has been added; a totalizer readout when in Parallel and Series modes.Unfortunately the latest FW that supports this is not compatible with earlier HW.Somewhere IIRC I have a rework doc which when found I'll shoot it to your email.

author: tautech
author_rank: Super Contributor
timestamp: November 18, 2023, 09:26:01 am
content: A warranty repair just done...installed the new version control PCB with uprated bridge rectifier.

author: MathWizard
author_rank: Super Contributor
timestamp: November 19, 2023, 04:24:52 am
content: My 3303 must be over 3yrs old by now. I had it open already tho. Do these have a fan though ? I can't remember seeing one or ever hearing 1. I hardly ever use much power, so IDK.But thanks I'll remember to check the rectifier next time I open it up. I bet it's due for a de-dusting too.I have some quiet computer fans, that would use under 100mA at 5V. Maybe those fan's are too big, but if I had a little one, I'd put it over the control circuits and rectifier.I'm guessing the main PSU heatsinks have a fan already.

author: tautech
author_rank: Super Contributor
timestamp: November 19, 2023, 06:16:34 am
content: Quote from: MathWizard on November 19, 2023, 04:24:52 amYup, smart fan and at low power it will not spin up from its normally very low RPM.QuoteTBH don't worry about it until you have an issue which for some years we never did so maybe just a bad batch of rectifier bridges caused these problems.I suspect design was using most of the 2A available from those tiny bridges and sus ones gave more failures.Now with a much better bridge in the redesigned HW there should be now more problems.

author: opiwahn
author_rank: Newbie
timestamp: March 15, 2024, 10:38:40 am
content: Quote from: tautech on November 18, 2023, 09:26:01 amI bought a brand new SPD 3303X-E (in Sept. 2023) and I wonder whether it could be affected by this reboot issue (up to now no problems yet). The hardware version is reported to be V6.1, can anybody tell me if this includes the uprated rectifier? I could open it up, but I don't want to break the warranty seal ... Thanks!

author: tautech
author_rank: Super Contributor
timestamp: March 15, 2024, 07:41:56 pm
content: Quote from: opiwahn on March 15, 2024, 10:38:40 amWelcome to the forum.Check the display symbols when in Series or Parallel mode.The newer HW has more than just a symbol shown in these modes.

author: opiwahn
author_rank: Newbie
timestamp: March 15, 2024, 08:59:58 pm
content: In parallel and serial mode, there is an additional blue text field which displays the added voltage/current. Is it this text field I have to look for?

author: tautech
author_rank: Super Contributor
timestamp: March 15, 2024, 09:25:45 pm
content: Quote from: opiwahn on March 15, 2024, 08:59:58 pmYep, indicates latest HW.

author: 44kgk1lkf6u
author_rank: Regular Contributor
timestamp: August 19, 2024, 04:16:26 am
content: I want to point out that it is not necessary to remove the broken bridge rectifier. It breaks with 1 of its 4 diodes either being open or having a large resistance. It is only necessary to add a good diode in parallel with the bad diode. In my case the broken diode was connected to the fuse. So I soldered a diode between the fuse holder and the linear regulator. It is the SOIC-8 chip next to the fuse and the connector.As this Florida man pointed out, it is hard to access the other side of the board to remove the bad bridge rectifier.https://www.eevblog.com/forum/testgear/sdp3303x-hiccup/

author: qpit3a
author_rank: Contributor
timestamp: August 19, 2024, 04:36:21 am
content: Hi yeah true but given consensus is bridge fails due to heat and that it is under-specified then probably best to replace with upgrade as rest of bridge probably will fail eventually.

author: tautech
author_rank: Super Contributor
timestamp: August 19, 2024, 04:43:27 am
content: Quote from: 44kgk1lkf6u on August 19, 2024, 04:16:26 amYet the control/front panel PCB is not at all difficult to remove.A few leads, and screws and the complete front panel is free along with the control PCB.Binding post screws and PCB mount screws removed the PCB can be worked on with ease and another replacement rectifier solution fitted.As it's for LV AC and the DC smoothing circuit remains on the PCB a replacement bridge can be mounted remotely with a 4 wire loom to a place where it's most convenient for those undertaking this repair.With care and control of wayward swarf, one of the main heatsinks can be drilled and tapped to provide an excellent mounting position for a remote bridge.It should be stressed that careful heat shrinking/sleeving of any wires be undertaken to prevent any shorts and care also with connections being correct. THe PCB is clearly marked as in expected for a bridge, AC + AC - as is normal for a bridge too.Don't muck this up......

author: tautech
author_rank: Super Contributor
timestamp: August 19, 2024, 04:46:30 am
content: Quote from: qpit3a on August 19, 2024, 04:36:21 amNot IMO.Early units hadzerofailures then something changed, where I suspect a different supplier was used or the bridge manufacturing process was changed....or both.

author: parawizard
author_rank: Regular Contributor
timestamp: November 03, 2024, 11:25:44 am
content: Realized my barely used SPD3303X-E has this issue. Bought it end of 2021. Was troubleshooting a Lenovo Legion laptop power rail short and the thing kept reseting by itself under load and fully idle.Siglent wanted me to send it internationally for warranty repair. Decided to fix it myself. One 470uF 50v Lenon cap spewed its guts out onto the giant cap next to it. All other caps tested good in circuit with ESR70.Bridge rectifier is the 2W10 unit which self destructed while desoldering. Thing really doesn't look very hardy. Going to bodge a much larger single in line bridge rectifier. I am replacing surrounding caps with good 105c@10000 ones as well.

author: tautech
author_rank: Super Contributor
timestamp: November 03, 2024, 07:09:23 pm
content: Quote from: parawizard on November 03, 2024, 11:25:44 amDud cap is on the Power PCB ......never seen one of these give issues......yet.Ohio NA HQ would have replaced both PCB's with the latest versions.

author: parawizard
author_rank: Regular Contributor
timestamp: November 04, 2024, 02:22:16 am
content: Quote from: tautech on November 03, 2024, 07:09:23 pmI guess mines a special caseQuote from: tautech on November 03, 2024, 07:09:23 pmLikely. Though it's going to cost me almost 100 CAD (Like 20% of the cost of the PSU) and a couple hours of my time to get it to them. I could get hit hard by customs on the way back over the border if something is off with the paperwork. Thing could get damaged etc. Or I could just recap some stuff, learn about the thing and replace that bridge rectifier instead.

author: tautech
author_rank: Super Contributor
timestamp: November 04, 2024, 06:40:28 am
content: Quote from: parawizard on November 04, 2024, 02:22:16 amWith the photographic evidence you have supplied here and the 'known' faulty bridge reboot issue you might have given them the option to supply you the parts for repair.

author: parawizard
author_rank: Regular Contributor
timestamp: November 06, 2024, 11:18:01 pm
content: Quote from: tautech on November 04, 2024, 06:40:28 amI agree. I did ask them. They declined.Parts came in from DigiKey today. Installed new 470uF caps and referenced factory pictures to make sure no shenanigans with polarity. Turns out the cap that had the blow out was in opposite of the silkscreen.Replaced caps around rectifier and bodged in a 4A SIL.Edit: The + leg looks like it's laying across the - trace but its actually got more than enough space below it. Just perspective of the shot.

author: parawizard
author_rank: Regular Contributor
timestamp: November 07, 2024, 01:51:58 am
content: After about an hour with the case off it's about 70°C. Seems a lot more reasonable than the original part.

author: parawizard
author_rank: Regular Contributor
timestamp: November 11, 2024, 09:10:30 am
content: Has been working nicely without any restarts on the bench since the repair. Thanks to everyone who contributed to this thread.