SPD3303X Hiccup - Page 1
Forum section: electronics / testgear

author: mawyatt
author_rank: Super Contributor
timestamp: August 18, 2024, 11:12:54 pm
content: For some reason we can't locate the thread that references the overheating Bridge Rectifier in the SPD3303X causing the PS to Reset.Disclaimer, this is NOT recommended, approved, nor good engineering/repair, work just simply lazy temporary solution!!We have little patience and time, and the CEO already has tasks aligned for us; fix the dishwasher, clean the rug cleaner, measure the pool chairs for fabric replacement (now that's a real PITA as we've already done a couple), remove the baseboard in the back bedroom, take the garbage out and so on!!When our SPD3303X Hiccuped the other day, we thought, "yep we need to replace the overheating bridge rectifier", however we have 3 SDP3303Xs and that's a lot of work!!After taking the culprit SPD3303X cover off and locating the Bridge Rectifier, we began to understand what was entailed in replacing such, realizing no way were we going to remove the front panel PCB, remove rectifier, replace such, reinstall PCB, and so on, and for 3 PSs, way too much work!!So we began to think adumb, cheap, easy, lazy, redneck patchwork,procrastinating solution, and came up with "lets just put a heatsink on the Bridge Rectifier for now on the only PS that has had a Hiccup, and see how this works!!"Well, it's been running a couple days now without a Hiccup (Reset)!!Anyway, we've justified our solution for now as it's apparently not Resetting, so "If it ain't broke don't fix it"BTW we've noted this particular SPD3303X so we won't use it in any critical applications (we have 2 others). Much later when time permits we'll tackle this with the proper rectifier replacements, we already have those in-house!!Best,

author: Kean
author_rank: Unknown
timestamp: August 18, 2024, 11:39:26 pm
content: It would be good to fix the product code in the subject - it should be SPD3303X not SDP3303XMaybe you were also searching for old posts using the wrong code?

author: KungFuJosh
author_rank: Super Contributor
timestamp: August 18, 2024, 11:42:22 pm
content: https://www.eevblog.com/forum/repair/siglent-spd3303x-e-reboot-problem/https://www.eevblog.com/forum/repair/siglent-spd3303x-e-rebooting/Some of them already have heatsinks on that part. I don't know why they all didn't, but even with that, some have failed.My DC Load might actually show up soon, we'll see how mine does.Thanks,Josh

author: tautech
author_rank: Super Contributor
timestamp: August 18, 2024, 11:49:01 pm
content: Quote from: KungFuJosh on August 18, 2024, 11:42:22 pmThe bridge in question only supplies the digital circuitry therefore PSU loads should have no additional effect on its loading.

author: KungFuJosh
author_rank: Super Contributor
timestamp: August 19, 2024, 12:01:27 am
content: Quote from: tautech on August 18, 2024, 11:49:01 pmI thought it got hotter under load? How can I test that part?

author: tautech
author_rank: Super Contributor
timestamp: August 19, 2024, 01:32:08 am
content: Quote from: KungFuJosh on August 19, 2024, 12:01:27 amIf the one diode in the bridge fails these PSU can go into a reboot cycle at cold boot but can also start acting up soon after boot. I've seen both.Whenever they start acting strangely the tiny 2A bridge is the first suspect.

author: mawyatt
author_rank: Super Contributor
timestamp: August 19, 2024, 01:36:37 am
content: Quote from: Kean on August 18, 2024, 11:39:26 pmGet this mixed up all the time, thanks for pointing it out, probably reason we couldn't find anything with the searchBest,

author: RoGeorge
author_rank: Super Contributor
timestamp: August 19, 2024, 06:48:55 am
content: Not sure if that is an optical illusion from the photo angle, but the top of the big capacitor right underneath the radiator looks like it already started to bulge. I would check its ESR/capacitance.Apart from that, the electrolytic capacitors are very close to the heat source(s). A layer of Kapton auto adhesive tape around the capacitors might help, only on the side with the heat source(s), so to reflect the infrared away from the capacitors.

author: mawyatt
author_rank: Super Contributor
timestamp: August 20, 2024, 02:59:36 pm
content: Here's a thermal image of the Bridge Rectifier with heatsink and area around, things are very warm including the caps. However the one cap isn't bulging, it's just the angle of the image. The Max Temp is the T0-92 device (Regulator?).After about 4~5 days, we haven't experienced a reset.Could someone with a new 3303 post a thermal image of this area to comparetemperaturestemperature distribution?Best,

author: Sorama
author_rank: Frequent Contributor
timestamp: August 20, 2024, 05:40:55 pm
content: a quantitative measurement using IR won't be possible.First you would have to determine the emission factor, secondly you're measuring a metal (the heatsink) which has a low emission and therefore hard to measure by IR.A (qualitative) measurement with the same IR camera from the same angle would give a representative impression of the heat that is generated over there.

author: ebastler
author_rank: Super Contributor
timestamp: August 20, 2024, 07:15:39 pm
content: Quote from: mawyatt on August 19, 2024, 01:36:37 amI think it's an acronym --SiglentPowerDoohickey. At least that's how I remember it.

author: KungFuJosh
author_rank: Super Contributor
timestamp: August 20, 2024, 07:38:31 pm
content: Quote from: ebastler on August 20, 2024, 07:15:39 pm100%! That's how they do all their acronyms. Like theSiglentSignalGadget.

author: mawyatt
author_rank: Super Contributor
timestamp: August 20, 2024, 08:05:48 pm
content: Quote from: Sorama on August 20, 2024, 05:40:55 pmWe know, thanks, should have said "compare temperature distribution", but more interested in how the components around this area are spread relative temperature-wise as this area is a "hot spot"!! Everything in the area seems heated up, and wonder if this is due to actual internal dissipation or just localized conducted heating.We did "look" at the Black Anodized Heat Sink utilized with the cheap UT-260B IR Camera just for sanity check, used our MHP30 as a heat source just to "see" if things were in the ballpark.Anyway, another "view" with a newer 3303 might help us understand!!Best,

author: tautech
author_rank: Super Contributor
timestamp: August 20, 2024, 09:22:59 pm
content: Quote from: mawyatt on August 20, 2024, 02:59:36 pmQuoteRectifier stage has been reworked now Mike:The only reason we've had to lift the covers on these PSU's are for bridge failures yet early units gave zero problems.

author: thm_w
author_rank: Super Contributor
timestamp: August 20, 2024, 09:44:21 pm
content: Quote from: Sorama on August 20, 2024, 05:40:55 pmHave you ever actually used an IR camera? Black anodized aluminum has an emissivity of 0.82-0.86. Which is fine. Even if it wasn't you can see the plastic package right underneath (would be around 0.9).https://www.design1st.com/Design-Resource-Library/engineering_data/ThermalEmissivityValues.pdf

author: mawyatt
author_rank: Super Contributor
timestamp: August 20, 2024, 10:49:50 pm
content: Quote from: tautech on August 20, 2024, 09:22:59 pmCertainly a bigger bridge rectifier!! Where is the TO-92 component located?A good thermal image of this area would be useful to see how things are distributed wrt version we have.Best,

author: tautech
author_rank: Super Contributor
timestamp: August 20, 2024, 11:31:17 pm
content: Quote from: mawyatt on August 20, 2024, 10:49:50 pmSorry Mike, dunno and as old HW is a straightforward fix we aren't stocking any new PCB's to get an image from.

author: TheDefpom
author_rank: Frequent Contributor
timestamp: August 22, 2024, 12:00:56 am
content: Reworked but still got caps right next to something that gets hot... This is a pet peeve of mine, I come across it all of the time, designers putting capacitors right next to heat sinks or things that get hot, even moving the caps 10mm further away would make such a huge difference !WHY do people design things so it heats the caps up, this makes them fail much sooner... so instead of lasting 20 years it might last 10.

author: tautech
author_rank: Super Contributor
timestamp: August 22, 2024, 12:08:23 am
content: Quote from: TheDefpom on August 22, 2024, 12:00:56 amBut does it ?Until someone places a TC on the new bridge or does an IR measurement we just don't know..

author: Sorama
author_rank: Frequent Contributor
timestamp: September 15, 2024, 09:35:23 am
content: Quote from: thm_w on August 20, 2024, 09:44:21 pmAs a L2 Thermographer I use Flir IR cameras all day long.So yes.Emission of 0,8x is rather low, so measured temperature is pretty off.TS wants to see the impact of the heat on the other components, but they do have very different emission factors (like the blinking alu cover of a capacitor).I bet emission factor of the used camera was not even set to what it should be.So even if it gives ‘nice’ ir pictures, they certainly won’t tell much (actually nothing at all) about the individual temperature of components.

author: MathWizard
author_rank: Super Contributor
timestamp: September 26, 2024, 10:33:12 am
content: How much dusst builds up in these Siglent machines? I own a few now, including a PSU, it's time I take it apart again and see if it needs vacuuming out.Overall I'm very happy with my SPD3303X. I never really need high power, or anything that seems to stress it much. Someday, I should do some loads test with it on a scope, and maybe check a few temps.I want to get another 1, or maybe the newer version.Hey Tautech, I was trying to find some page to ask you about this memory upgrade to some very expensive Siglent scope. So markup's aside, is this just the price of some super fast memory, or do they upgrade other chips too ??$4,500 maybe CAD, but thats still ~3,150USDhttps://www.transcat.ca/brand/siglent-store/oscilloscope/siglent-sds7000a-1gpts-memory-depth-upgrade-to-1-gpts-for-sds7000a-oscilloscopesSeems like a lot of money. And how does all the memory chips in these super expensive TE compare to GDDR6 like in the best GPU's money can buy ?

author: tautech
author_rank: Super Contributor
timestamp: September 26, 2024, 10:41:06 am
content: Quote from: MathWizard on September 26, 2024, 10:33:12 amThe 1GB memory depth license is just a SW switch, albeit an expensive one but probably priced to undercut opposition.

author: ebastler
author_rank: Super Contributor
timestamp: September 26, 2024, 12:50:01 pm
content: Quote from: MathWizard on September 26, 2024, 10:33:12 amThe price is determined by the fact that Siglent knows you could afford the SDS7000. So you must be able to afford an expensive memory upgrade too.Another way to look at it is what tautech wrote: It's enough for Siglent to price it a bit lower than the high-end competition. Then the price is no longer considered a rip-off but "in line with the market".

author: mawyatt
author_rank: Super Contributor
timestamp: September 28, 2024, 08:13:12 pm
content: Update on the heatsink use.Just had another "Hiccup", so this isn't solving the bridge rectifier overheating problem.Now we'll need to replace the rectifier as we are out of the 3 year warranty periodBest,

author: tautech
author_rank: Super Contributor
timestamp: September 28, 2024, 08:23:27 pm
content: Quote from: mawyatt on September 28, 2024, 08:13:12 pmAnother replacement bridge fitment solution using a standoff popped up a day or so back here:https://www.eevblog.com/forum/testgear/siglent-spd3303x-power-supply-turn-off-and-on-all-the-time/There's 2 connectors from the front PCB to Power PCB that can be swapped so take care to mark them so they don't get swapped.Full removal and refitting of the front PCB is straightforward other than that.IIRC you will require 3 sizes of Torx drivers.

author: ArcticGeek
author_rank: Regular Contributor
timestamp: September 29, 2024, 12:04:14 am
content: I tend to think that this might be a good candidate for a MOSFET-based bridge rectifier in order to reduce the heat dissipation, like what is shown here:https://www.powerelectronictips.com/power-supply-circuit-mosfet-bridge-rectifier-gives-high-efficiency-for-low-voltage-high-current-ac-dc-supplies/It would require a small PCB to be etched to hold the MOSFETs and other components. I actually sold my SPD3303X-E some time ago, but if I still had it I would be tempted to make up a small board to replace the bridge. This would get rid of the heat almost completely so you wouldn't have to worry about surrounding parts getting too warm.Food for thought.Cheers,

author: tautech
author_rank: Super Contributor
timestamp: September 29, 2024, 12:27:30 am
content: Quote from: ArcticGeek on September 29, 2024, 12:04:14 amOTOH, any diode or bridge run near to max ratingwillproduce heat.Like most design these days components get pushed where once designers were much more conservative....which aided longevity/reliability.Instead of a 2A rated bridge, latest HW runs an inline package of maybe double the rating...maybe pics I took of them display the device # IDK.Edit to addThe updated inline bridge in a unit I have here is KBU1010, a 10A 1kV bridge.https://www.mouser.com/datasheet/2/1451/kbu1010-3477620.pdf

author: mawyatt
author_rank: Super Contributor
timestamp: September 29, 2024, 03:01:56 am
content: We replaced the OEM rectifier with a 4A version that's in a flat plastic pack (like the new PCB version). Bent the leads to arrange them like the OEM version and fit directly to PC. This is higher off the PCB but should give better thermal results than the smaller circular OEM bridge rectifier.Getting the OEM rectifier out was the most difficult part, everything else wasn't difficult. These things are built like tanks and not difficult to disassemble. The banana sockets are solid chunks of metal bolted directly to the PCB, looks like they could handle 100s of amps, it's a shame they didn't get the socket depth and spacing correct. Hopefully the new 4000 series fixed this, but hope they kept the massive metal shaft that bolts to PCB connection.Results are OK so far, will let run for a few days/weeks.Best,

author: tautech
author_rank: Super Contributor
timestamp: September 29, 2024, 03:16:17 am
content: Quote from: mawyatt on September 29, 2024, 03:01:56 amYes this was the HQ recommended rework method that while very achievable, is an ugly bodge IMO and very never keen on it, so have always fastened the bridge remotely and made a short wire loom to it.Others might like to see any pics Mike unless it's already a closed case......

author: mawyatt
author_rank: Super Contributor
timestamp: September 29, 2024, 03:30:14 am
content: Didn't look that bad. It's all closed up now and back on rack.Best,

author: mawyatt
author_rank: Super Contributor
timestamp: September 29, 2024, 12:23:56 pm
content: Okay, took the supply down and reopened.BTW ran overnight without a HiccupRob, here's a few images of the Bridge Rectifier replacement.These supplies take a lot of flack, and mostly justified IMO (banana terminal spacing and plug engagement, quirky UI, and now the rectifier issue), but do provide a good, stable, clean, accurate output that is really good in this price class, and really like the bright display with crystal clear large numerics.Once calibrated they produce accurate stable outputs in both current and voltage, after all that's what a good supply is supposed to do!! In fact what led us to rediscover the "Hiccup" was a dead garage door opener, we had replaced the battery recently and now dead again. First suspect was bad battery, yep it was dead but why as just replaced? Hooked up 3303X set to 3.0 volts and 10mA current limit to battery holder, the 3303X showed a 1mA current drain when Opener was OFF?? Checked current with KS34465A to verify 3303X 1mA reading, yep was ~1mA. Tried cleaning the Opener, but same 3303X 1mA reading OFF state result and no need to verify with DMM.Still believe these are the best value at this price (especially with "expansion"), sure there are "better supplies" like the GPP-4323 and new SPD4000 series, however these are higher priced.Best,