#188

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Withe help of a viewer we have finally found a way to increase the Over Voltage Protection on the server power supply. So many thanks to Amundsen for pointing me in the right direction.
*************** Warning ************************
I did get an electric shock while making this video and i was lucky it was only a slight zap. It could have been a lot worst, so please please DO NOT play with these power supplies unless you know what you are doing!
**************************************************
The last video in this series will be a revisit to the setting the output to 13.8V and play with that resistor value to see how far we can go. Note there maybe capacitors that have a voltage rating that may not be much higher than 12V as the circuit was never intended to go higher than 12V.
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Опубликовано:

5 фев 2023

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Комментарии : 51

@TheEmbeddedHobbyist 8 месяцев назад

I've just signed up to "Buy me a coffee", but no need to buy be a coffee! a comment is just as good 🙂 bmc.link/TheEmbeddedHobbyist

@BV-tb9wi 8 месяцев назад

A 10K resistor for the OVP worked for me without any problems (A load of 15A@15.5V was no problem). With a 10K resistor as well for the voltage potentiometer, the voltage range would be 14.5 ~ 15.5 volt. Note that the internal capacitors are rated at 16V. In another video, the person recommends reversing the fan so it pushes air into the power supply instead of pulling it out of the power supply. Also it's recommended to move the temperature sensor (glued with white glue on the capacitor on the left in the back) to the heatsink at the back. (CAUTION : The heatsink on the front can still contain a voltage of 100~200 volt. Don't touch it with your bare hands while/after testing). Some observations : When working with this power supply opened up, be aware about the huge capacitor (68uF / 300V) in the primary circuit. Even with a load attached, it holds on to the rectified mains voltage for about 10~20 minutes. If you would touch the heat sync in the middle, you might get a nasty shock. I wasn't able to use variable resistors wired outside of the case for the resistors for the OVP and voltage adjustment. In another thread is was mentioned that the wires will pick up too much interference and cause the power supply to trip instantly. Using normal resistors as in the video indeed worked fine. The PD30 power supply seems to have the same logic board. For running some power tools, I had to add some additional capacitors over the + and - externally. The internal capacitors combined are 4400uF/16V. Those tools would give spikes of 25A when they start running but they would settle down at 15A once running. Replacing the internal capacitors requires a big soldering iron because of the ground/power planes are huge and absorb more heat than a 30W iron can produce. Just applying two 30W for a while did the trick. I haven't been able to get the voltage higher than 15,7 volt with low value resistors though. The OVP isn't even tripping but there somehow seems to be some sort of maximum voltage (probably due to other components on the logic board).

@TheEmbeddedHobbyist 8 месяцев назад

Wow that's a lot of hard work you have put in thanks for sharing. I would not normally go more than 80% of a capacitors voltage rating. I see the original design is about 75% . taking it to 13.8 takes it up to 86% i would not want to go any higher as your pushing the ratings a bit hard, not good for a happy long life. again thanks for sharing.

@zygmunt73 8 месяцев назад

Thank you, I modded my PSU with 22k resistor, and 47k + 10k for OVP. Ive got 13.87V. Thanks again

@TheEmbeddedHobbyist 8 месяцев назад

Glad that you found it useful. thanks for letting me know.

@razortractor4009 5 месяцев назад

Very nice detailed video thanks. I am fixing to do a couple of these power supplies and your video has helped a lot .Keep up the great work.

@TheEmbeddedHobbyist 5 месяцев назад

Thanks for taking the time to comment, all comments are welcome but yours makes my day. Thanks again.

@zing913945 Год назад

T E H Thanks for the excellent adventures in your series of videos. This is very timely as I ordered a power supply and received the identical PS you have modified. I am looking forward to trying this on my radios. All the best

@TheEmbeddedHobbyist Год назад

Just remember that they can bite so leave them unpowered for a while before going in side. I'm currently looking at a 25A highspeed over voltage/current trip to go on the output to protect the radio's I've got plugged in to the output,

@amundsen575 Год назад

glad you posted this video, I set my PS to 13.85 for general automotive use, l load tested with a stainless welding rod 3/32"(2.4mm) 36" long coiled up on a .75 mandrel as a load ~60A will glow red, working good. Got shocked as well as the heat sink in the middle of the PS is connected to mains insolated by a gasket, in my case a silicone gasket, I usually use an isolation transformer when working on SMPS as not to damage the scope, also should have a current limiting incandescent bulb in series connecting to mains

@TheEmbeddedHobbyist Год назад

Well thanks again for finding the OVP comparator; I think I used the internal body resistance as a current limit. The worst thing is that as there is rectified main or DC to give it it’s correct name, a shock from this will cause you hand to contract and hold on even more. At least AC tends to throw you away about 50 times a second in the UK. I’m on the lookout for an isolation transformer but only the 240V to 110V site transformers are going cheap, at some point i may just buy 2 and connect them back to back. So 240V to 110V and back to 240V should be extremely safe as two means of protection (MOP’s as they like to say in elf and wafety standards like the LVD). Thanks again.

@VladGoro25 5 месяцев назад

if u use 25k for V pot and get ~13.4-13.9V, do i need to change OVP by adding resistor to PIN 3 ? thanks

@andymouse Год назад

It's apparent that I don't always get notified ! I saw the flash as you got bit...not fun. Good amount of patience but you got the 56K on there and it all worked....Squeak !!!!!

@TheEmbeddedHobbyist Год назад

Maybe i'll start posting at midnight when your awake. :-0

@andymouse Год назад

@@TheEmbeddedHobbyist Nah its a bad habit !

@LeeKirkman88 7 месяцев назад

When i was younger i got a shock off a 500w tube rf amplifier. It threw me back into me chair and my head was buzzing lol. The risk is with large electric shocks like this is can put damage on the heart. So this stuff is no joke.

@TheEmbeddedHobbyist 7 месяцев назад

It takes so little current to give you a very bad day, thankfully the skin can try and keep it out.but 400V dc is way beyond it limit to protect you. Best form of protection is one hand behind your back and allowing it to fully discharge before going anywhere near it.

@DaftOldMan Год назад

That's why so many things have a sticker on them. "Always unplug from the mains"😁

@TheEmbeddedHobbyist Год назад

i was unpluging it from the main, just not the way they intended. :-)

@AJB2K3 Год назад

Ow, been there, felt that!

@TheEmbeddedHobbyist Год назад

It did rattle the brain for a bit so at least I know I still have one:-)

@LeeKirkman88 7 месяцев назад

That camera for close ups is pretty nifty stuff

@TheEmbeddedHobbyist 7 месяцев назад

Thanks

@romanmonogarov 10 месяцев назад

Is it possible to raise the voltage to 14.4 volts ? to charge LiFePo4 batteries

@TheEmbeddedHobbyist 10 месяцев назад

Yes just play with the values of the resistors for the output and the over voltage protection. But without having looked at the ratings of the caps you could be getting close to their max voltage ratings. I was happy to raise it by a volt or so but go above that and the risks increase that it might go bang.

@mikesgarage394 10 месяцев назад

Great info Why didn't you just put the resistor on the back of the board?

@TheEmbeddedHobbyist 9 месяцев назад

That's the connection points i was told about, then tested to make sure it worked. Not sure if the connections come through the board, i could have looked but the points worked for me.

@vovakvas2013 8 месяцев назад

Hello! I watched your video, it is quite interesting, but there is an easier option. can send a link! Please tell me what the two regulators on the board are responsible for?

@TheEmbeddedHobbyist 8 месяцев назад

I don't have a schematic of the power supply, so the first one in the original video was the output voltage control. the one in this video was for the ovp to increase it's trip point. What the rest do we would need a schematic which are i would say impossible to find on the interwebs

@vovakvas2013 8 месяцев назад

@@TheEmbeddedHobbyist Increasing the ovp is not a problem, there you need to solder a 6.8 ohm resistor to the 3rd leg of the microcontroller and the 23rd output on the board. Accordingly, I think that those regulators lose their function!

@TheEmbeddedHobbyist 8 месяцев назад

@@vovakvas2013 In that case i think this way as shown in the video is a better way to the same end. i think it's better to adjust the feedback to the control circuit by adding these resistors, as it leaves the amplifiers working as normal but just in a modified area.

@merseyradar6881 Год назад

Nice video and good progress TEH , Great work also by "mamundsen" over on eevblog forum. I dont think I would be brave enough to attempt smd by hand in this location. I may try regular 1/4w through hole resistor to the alternate ground point near fan connector like mamundsen did. I have an untouched PSU and I will report back with factory values/settings of the other pots if reqd. Good video. Thanks.

@TheEmbeddedHobbyist Год назад

Thanks, I don't expect the other pot to have a damaging affect as it’s available to adjust from the outside through a hole. But it would be nice to get it back to where it should be, or even knowing what it adjusts. But had it powering a radio this morning and it seemed to be quite happy at 14V. The SMD was just a clean way to do it and the fact i have more SMD resistors than TPH ones. :-)

@merseyradar6881 Год назад

@@TheEmbeddedHobbyist Hi TEH I am thinking of using this psu for amateur radio also. I can just about do 0603 or SOT-23 packages but only just. Is there q way to back off the voltage a little to 13.7 using the pot in reverse of method in visit No1 to boost the voltage ? Todays radios are finicky with 14v + thinking icoms in particular for some reason. It seems you are in the sweet spot though but I would prefer 0.5v or so for headroom. Tried this PSU with 100w rig yet ? Good work TEH.

@TheEmbeddedHobbyist Год назад

Sorry this one got held for review and i just found it. the pot on the side of the psu, the left hand one looking at the pots adjusts the output voltage. so if you used the value of resistor i used in the first video you should be able to adjust the output to between 13 - 14V with ease. used to power a yaesu ft-897 but only up to 20watts on 70cm, looking at building a overvoltage cut out soon to add to the output.

@phuchai26 Год назад

How do you make the output current 14v? can you show me

@TheEmbeddedHobbyist Год назад

if you go and watch video "#073 converting HP HSTNS PD29 to 13 8V" ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-xZCdlzEaaUk.html this will show you how to increase the output voltage. Then you need to watch "#188 HSTNS-PD29 Over Voltage Protection increase success :-)" ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-ZPbhtYwK95M.html to increase the over voltage trip point. I would not go much above 14V as I've no idea of the voltage rating of any capacitors on the output.

@thecool2328 Год назад

Is this applicable for PL28 version

@TheEmbeddedHobbyist Год назад

Sorry but I don't know what pcb the PL28 has so I can't say.

@mykolahonchar6641 Год назад

Hello! I have the same PSU. But unfortunately this method didn`t work with my 🙁. Can you get 13,8V from start? Or you did with it something before this? I can`t get more then 12,6V. Even when I did as in video - nothing changed.

@TheEmbeddedHobbyist Год назад

Hi yes there is the first video i did on this PSU. #073 converting HP HSTNS PD29 to 13 8V ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-xZCdlzEaaUk.html the link to it. you just need to add a resistor to increase the set point. Hope this works for you.

@mykolahonchar6641 Год назад

@@TheEmbeddedHobbyist This video was much helpfully with me. My problem was solwed. Thank you so much! The same method also works for the power supply HSTNS-PD28.

@fredflintstone1 Год назад

oh a shocking video 🙂 did it shock you???? 😄

@TheEmbeddedHobbyist Год назад

It was shocking how shocked I was but the shock, but seeing the funny side of it means that one of my 9 lives has been given back to the gods of electricity.

@fredflintstone1 Год назад

@@TheEmbeddedHobbyist you get the best ones from an old flash camera capacitor 🙂

@TheEmbeddedHobbyist Год назад

@@fredflintstone1 I agree a jolt from a capacitor is always a wakeup call. They can charge up slowly from a high impedance source then discharge it through you in an instant.

@andymouse Год назад

SQUEAK!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

@fredflintstone1 Год назад

@@andymouse Cheese!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

@john411ize 4 месяца назад

How many amps with this mod?

@TheEmbeddedHobbyist 4 месяца назад

Hi I don't know, I don't have anything that could load it to its max. I use it to power a 100W HF radio whi h it does without its fan coming on. If you stick with it being a 750W supply i would not try and draw more than 54A's 750/12 = 62.5A 750/13.8=54.4A. Ut being a used PSU i would not want to run it put 80% of max load anyway.