Just a FYI when doing this mod, double check your soldering connections on the resistor leads on both the variable pcb board and on the OVP board! I didn't have one end of the resistor soldered good to the SOT transistor leg, on the OVP board, it came loose when I put the rubber pad up against the PCB and didn't know it. Powered up the PS and fan reved out big time and blew out some component. Still powers on but no green light or output voltage. It's trash now. Just wanted to let everyone know.
Thanks, 1/4w 6.8k for voltage control 13.4v - 14.4v. For OVP I used 8.2k and supply set to 14.2v. Already tested on my BMW e60, on 60amp load voltage down to 13.9 volts. Used for 2 hours programming session, work like a charm. Thanks again.
I'd love a full video or hell even just a comment on how you identified the OVP circuit. I created the first YT vid on how to get this PSU to turn on, there was not a single page on the internet with any info, I basically messed around with the PSU for an evening, probing and taking notes, noticed the shorter pin traces on the end and assumed they might have something to do with turning it on because you would want all other pins connected first before "activating" it, but I admit I tired a few different pins together with high impedance resistors before I had it 100% figured out. But, to find where the OVP circuit is and how it works and then actually modify it, I had no clue. I'm very grateful for your video, I used to run mine at 14v but with a load it would sag to 13.4ish, now I have it set to 15v, and I have another volt if I want to use it! Brilliant! I really love this psu, they are tiny and super quiet too!
Is there any info on running 2 in series? I had it working for a bit but ovp was actually still on on one of them once I fixed it… once I connect to load (29.2v 300ah battery) they both turn off same time. One isolated from ground. And I did have them working at 14.7v each but with a horrible sound from the ovp. Now nothing once I fixed the ovp
What do you mean by "fixed the OVP"? Have you taken a look at my OVP triggering test results chart uploaded to EEVBLog?( thread titled "HP HSTNS-PD43 PSU Hack & Feedback Circuit (Partial)" - 3rd post down. ) Copy /paste the thread title including the quotation marks and "Google it". The 3rd post of the thread has a small thumbnail which can be clicked to open the triggering results chart and you can right click > save as to download the spreadsheet image. Also, you may want to check the load sharing pin features(one of the earlier comments here mentions that pin-5 from the edge on the underside of the output tab is the load share pin). Cheers.
In short, 15.87k in my case. I've commented here about a month ago a list of resistor values for voltages in the range of 12.66V ~ 15.50V. If viewing on a computer(not phone), then click "Sort by"(next to #Comments) and sort comments by "Newest first" then look several comments down from yours for details. Cheers...
@@RafKos If you are referring to the OP's (original uploader - Hopper's) OVP resistor in the video, it is 4.3k. According to my OVP triggering tests (for relatively low loads of 6~2 Ohms, or about 2~7A depending on set voltages) OVP resistances of 10k or lower seem to "disable" OVP (note within the low load ranges of 6~2 Ohm, 2~7A tested). If you want to keep OVP active for triggering at about 15.5~15.4V but not triggering below, then 10.5k seems optimal (for the low load ranges tested - I've yet to test in very high loads like 50~100amps range, which may require lower OVP resistances to prevent triggering at voltages to be set for use). For more details of my triggering tests, copy & paste "HP HSTNS-PD43 PSU Hack & Feedback Circuit (Partial)" including the quotation marks and "Google it"(or do a search). The first likely result will be the thread I started in the EEVBlog's Forum section with the same title. The OVP related info is in the 3rd post down. The first post contains my own manually probed schematic of this PSU's auxiliary board(which is shown in this video). Cheers...
@@tinkerman4774 Hi, thanks for your message. I need it for BMW programming. So I need 100-120 Ampers and 14-14.5 volts. Could you printed some covers in 3D for that model or you know somebody whos doing something like this?
@@RafKos I do not have 3D printing model, as I will be using a plastic brief case for my build. But perhaps "Jose_Jn BMW HiTech Retrofitments & Coding" might? If you haven't already, check out his video titled "ISTAP / ESYS 14v PSU Do It Yourself for BMW Flashing and Programming. Up to 80A!!".
My test of this PSU's modified OVP triggering over a range of resistances, voltages & (light)loads has been uploaded to the EEVBlog thread titled "HP HSTNS-PD43 PSU Hack & Feedback Circuit (Partial)" - 3rd post down. Can't link here as this comment would get (automatically?) deleted. If interested in how the OVP behaves, check it out (e.g. OVP is disabled for resistances of 10k and below, whereas to keep OVP active to trigger at around 15.40~15.50V without changing the output caps, the optimum resistance is in the range of 10.50k~10.60k). For more details search the thread mentioned above. Cheers...
@@BrianThorpe-l5bJust copy & paste "HP HSTNS-PD43 PSU Hack & Feedback Circuit (Partial)" including the quotation marks and "Google it"(or do a search). The first likely result will be the thread I started in the EEVBlog's Forum section with the same title. The OVP related info is in the 3rd post down. The first post contains my own manually probed schematic of this PSU's auxiliary board(which is shown in this video). Cheers...
Below are tested resistor values for output voltages 12.66V ~ 15.50V. { Resistor Values Are As Tested Without Rounding} 12.66V - 100.1k~103.5k 12.75V - 80.1k 12.80V - 71.0k 12.89V - 59.83k 13.00V - 50.63k 13.10V - 44.20k 13.20V - 39.09k 13.30V - 35.09k 13.40V - 31.82k 13.50V - 29.23k 13.60V - 26.92k 13.70V - 24.99k 13.80V - 23.36k 13.90V - 21.95k 14.00V - 20.64k 14.10V - 19.46k 14.20V - 18.43k 14.30V - 17.48k 14.40V - 16.62k 14.50V - 15.87k 14.60V - 15.20k 14.70V - 14.54k 14.80V - 14.01k 14.90V - 13.46k 15.00V - 12.91k~12.98k 15.10V - 12.45k 15.20V - 12.05k 15.30V - 11.64k 15.40V - 11.27k 15.50V - 10.68k Note: The reason I went through this range is because I'll be using this during automotive ECU programming to keep the battery charged up. I'll utilize a 100k multi-turn pot so I can adjust the output voltage from 12.8V up to 14.6V as necessary, much like how a car battery charger gradually increases its output voltage during the initial minute or two of charging. Cheers~ * Regarding OVP triggering: For triggering say at around 15.00V(+/- 0.5V?), OVP starts kicking in between resistance values of 11k~12k and up. BUT... the triggering is not just based on voltage, it is also dependent on current/voltage drop(i.e. at certain voltages, OVP does not trigger at say 2A loads, but will trigger at higher loads say 4A, 6A, ... etc.) so to get a clear picture of the spread of this "grey zone"(in which small loads don't trigger OVP, but larger loads do) it will likely be necessary to make a graph based on methodical testing of not only multiple voltages but multiple current/loads for each OVP hack resistance value under test, and test over a range of resistance values. I'll try to make such graph via an Excel sheet perhaps and upload on EEVBlog and update here when it's done. ** Update: The preliminary OVP triggering tests are done and uploaded to the EEVBlog thread titled "HP HSTNS-PD43 PSU Hack & Feedback Circuit (Partial)" - 3rd post down. Can't link here as this comment would get (automatically?) deleted. If interested in how the OVP behaves, check it out (e.g. OVP is disabled for resistances of 10k and below, whereas to keep OVP active to trigger at around 15.40~15.50V without changing the output caps, the optimum resistance is in the range of 10.50k~10.60k). For more details search the thread mentioned above. Cheers...)
@@ahmedbalobaid753(In reply to the now deleted question by ahmedbalobaid753 of whether variable resistors can be used... keeping in mind they can start from "zero" resistance, ... ) In short... YES! ( Update: Yes for voltage boosting, but NO for OVP mod if using a wire wound potentiometer - the wire wound pot's inductance messes up the OVP's feedback voltage and the OVP never triggers!) But you would not want to set it to start at "zero"(or close to it) unless it is used with other resistors so that the actual active resistance would be within safe ranges that would result in output voltages under 16V(or if the output caps are exchanged with higher values, then under that higher rating). If the pot were set to "zero"(or close to it) without any other resistors in series, the PSU will likely not turn ON(i.e. the fan won't run and the output will not be normal voltage), as the OVP would be triggered immediately (assuming the OVP hasn't been disabled with a similar very low resistor in parallel). In my current testing setup, instead of soldering resistors onto the PCB right away, I soldered on relatively long 2 wires(25AWG) one for the voltage hack and one for the OVP hack onto the PCB, and the other ends are connected to a small breadboard for testing with various resistors. Of course after testing, I won't be using the breadboard, but the wires will still be used so I can have a pot & trimmer (for voltage & OVP respectively), on the outside of the PSU. For the voltage hack, I started with 4 x 20k resistors(in series as needed) and 1 x 20k multi-turn pot(in series or on its own). For the OVP hack I started with 2 x 20k in parallel(for 10k) and one 5k multi-turn pot/trimmer in series or on its own depending on resistance setting. The grounding has been onto the main ground tab next to the 12V output tab, using alligator clips. I now have a 100k pot so I can do without the 4 x 20k resistors + 20k pot. This 100k pot will be used with a big multi-turn knob(which looks like a safe dial) on the power supply's enclosure panel (the PSU will be placed in a plastic safety brief case). Also, on a side note, when wires are initially soldered(instead of resistors), before any resistors are connected and grounded, the dangling wires seem to throw off the control circuit(perhaps due to wire inductance/capacitance or due to their acting like antennas for noise), and the PSU will not turn ON. I freaked out thinking I fried the cap or resistor to which the wires were soldered onto, but once the resistors were connected and grounded, the PSU fired up(i.e. turned ON, not catch on fire, h e he). In the case of OVP, if the resistance is too low, then OVP may not ever be triggered when needed, and would essentially make it seem like the OVP has been completely disabled. Some don't give a hoot as long as they can boost the voltage up, but having the OVP kick in before the output caps or perhaps some sensitive diodes & ICs in circuit blowup would be a smart move. Hence, my intent to keep testing for a thorough/clear picture of how the OVP behaves at various voltages and loads.
(Update comment copied...) My test of this PSU's modified OVP triggering over a range of resistances, voltages & (light)loads has been uploaded to the EEVBlog thread titled "HP HSTNS-PD43 PSU Hack & Feedback Circuit (Partial)" - 3rd post down. Can't link here as this comment would get (automatically?) deleted. If interested in how the OVP behaves, check it out (e.g. OVP is disabled for resistances of 10k and below, whereas to keep OVP active to trigger at around 15.40~15.50V without changing the output caps, the optimum resistance is in the range of 10.50k~10.60k). For more details search the thread mentioned above. Cheers...
Thanks, It works! My values: I wanted 14.4v for vehicle programming, For OVP board, I used 2 x 1/4w 6k resistors in series to get 12k. For the voltage output pot resistor, I used a 10k resistor instead of the 5.6k resistor. This gave me a voltage variation of 12.8 to above 16v! I was surprised to see it hit 16.4v briefly, but thankfully it didnt damage the outout capacitors which are only rated to 16v. After tweaking the 10k pot down the output is steady at 14.4v. I'll make a short video of my mod if anyones interested. Thanks for the video!
The voltage mod works fine but the crowbar does not.. I have spent four hours on three supplies... With 18k across the voltage. I get a nice range centered abour 14v...Go to 14.08v and the crowbar trips the supply with no crowbar resistor mod... No matter what resistance value I apply in the suggested location be it high or low the supply will happlily produce any voltage and no ovp kicks in.... 😢
Try connecting a load(e.g. some power resistors / a few amps perhaps) on the output of the PSU... *Update: apparently the OVP hack resistor may need to be a higher value depending on the desired triggering voltage threshold (e.g. 11k~12k and higher for kicking in at roughly 15V, +/- 0.5V depending on triggering load currents) .
Sir, do you have some advice on how I can find the volt share pin so I can probe around and find it myself on my flex slot PSU, it would be super appreciated if you would share how you identified it! And do those pins get connected in parallel between units? Finding official documentation on these PSUs is impossible. I bought the DPS-1400BB flex slot PSU and figured out how to turn it on and also increase the output voltage before there was any online guide whatsoever, so I uploaded a vid on how to do it on my channel. This vid will certainly help me to disable the OVP on my unit so I can get over 14.5v and Ill make a new video on that. 👍 Thanks buddy!
Excellent, works a treat. Also used 22k and 6.8k for 13.7V. Worth pointing out that you need a good soldering iron with a fine tip, also as someone else has said decent magnification to see what you're doing. Took me a couple of attempts to make the top joint of the 6.8k, 1st time I shorted it to the plated through hole below (before using a magnifier) and although it fired up and lit a 12v lamp the voltage collapsed when put under a real load. Came back to life when I stripped it back so seems quite resilient! All done now, so thanks again!
Finally completed probing & tracing out this PSU's side(auxiliary) PCB into a schematic. It is uploaded on EEVBlog ["HP HSTNS-PD43 PSU Hack & Feedback Circuit (Partial)"]. Any comments or answers to the questions in the thread would be appreciated in the EEVBlog thread or here. Thanks again... Cheers~
Thank you for this video, I needed a power supply for maintaining vehicle voltage above 13.5v with the ignition off. Used the 5.1k and 5.6k and was able to get it dialed in to 14.46v. full clockwise was below 14, and full counterclockwise was at least 15. I do not have a steady hand at all, so soldering was tricky for me, but I covered the area around the solder points with kapton tape and it worked great.
The 3.3k and 5.1k are working like a champ with the supply set to 14.9v. Nice to see how to mod these as the DPS-1200SBA supplies are getting harder to find (cheap) and these are plentiful.
Hi, this is a very good method for such supply as I have applied same method but supply is being shut down on applying a little load from out put so plz must guide for fix it
Great little vid buddy.. I,m about to hack mine which is more or less identical.. hp 750w 'pl 18. What size resistors do you reckon for it to sit at 13.8v.? Cheers buddy.. Keep up the great work.👍👍
Appreciate the info/video, thanks! Just one thing I'm confused about, why set the OVP to 16.3V while 16V and anything above is a self-destruct? Should you not use specific value to set the OVP to safer 15.8V? But it probably would be nicer if someone patched the PIC micro firmware to just adjust the OVP to 10-15.8V so , that's what some folks did to the bigger HP PSU.
