From what I have seen in the past is that when one increases the voltage on these switch mode supplies one must also derate the output amps accordingly. I would opt to place a small daughter board close to the output leads and allow one to switch between 12.x and 13.x volts, some items don't tolerate 13.8 volts if you plan on using this as a multipurpose supply.
Hi thanks for thge comment. I plan to use this with mobile transivers HF , VHF-UHF etc. 13.8 is the normal battery charging voltage so about what the radio's are expecting to see. I don't think I'll be going too close to the max rated current. max about 30A or 1/2 rated output so should be ok. One reason for not trying to change the over voltage protection is it should still cut out before it can over voltage my radio's
Great video ! I have resistors that will work but they aren't smd. Can I wire to the leg of the pot you hooked your resistance box to and then take it to ground ? Or do I need to solder the other end to one of the points your soldered the resistor to ? I thought things were small in 1970 when I took a couple electronics classes. A microscope for these old eyes would be handy
the resistors need to go the the same places, except for ground or 0V that end can go to any convenient 0V place. just make sure that the leads and wires are well insulated from the PCB.
Yes it worked for me. And everybody knows that when we increase voltage to 13.8 the amps decrease a little bit but overall wattage will be same I think there is no issue for components to handle it because its a very little difference between 12v and 13.8v. Nice video
A great video, thank you! I've just bought one of these on eBay and waiting for it to come in the post. I'm hoping to use it as a current source for vehicle electrical systems when performing software updates to modules when the engine is not running. With the mod in place, do you know what the lowest achievable voltage is using the pot?
Sorry I can't remember, but if you fit a different value for the resistor mod you could tweak it down a bit. Just remember to let the power supply sit for a few minutes after turning off, the high voltage left on the caps inside can easily kill.
What did you use to Energize the unit? I saw you switch it on and off. Or I should say it looked like you switched it on and off. I’ve used a 470 home resistor on mine and I can’t get it to energize. Let me know if you would.
Hi James, My unit has no problems turning on and off! I have a 390 ohm resistor that is switched between the left most track on the top of the PCB and the 4th one in from the left. why 390 ohms i don't know it must have been sitting on the bench, it's not a normal goto value.
@@TheEmbeddedHobbyist after I spoke to you, I was able to get it energized by shorting the left pens. I’m not sure why the resistor wouldn’t start it. But it’s working now, not with the resistor but by shorting it each time I use it. Thanks for responding. You’re very informative and I will continue watching your channel.
I got the same model PD29 And can energize the unit by short The left leg and the 4th leg without Any resistor in between. Question Is do you really need the 390 ohm resistor ?
Yes, 13.8V is the standard voltage for a 12V battery system while being charged. So it the standard input voltage for Ham Radio mobile systems. A 100W HF unit pulls around 20A’s so need a good size power supply. A linear is better option but they tend to be very heavy, so a switch mode is a compromise weight Vs electrical noise. looking at replaceing the 30V 30A variable supply I'm currently using with it for my HF rig,.
@@GnuReligion I have an old crowbar unit that trips at 14V I was going to put a 30A fuse between the output and the crowbar cct to protect for overvoltage and over current. The psu has overvoltage but you can't be too careful.
is there any other way to solder a resistor in that is not an smd resistor. One with a lead say soldering it to the 0 voltage point as others have done on the 4th pin back on the header pins that is 0 volts? I have the stuff but not the practice to solder something that small. that resistor looks like a 2402 24k what size is it?
Hi Bruce, the resistor was a 0806 which just fitted the gap. You could fit a 1/4W resistor between any easy 0V point and straight on to the variable resistor leg or the point highlighted with the resistor in some heat shrink sleeve but I found the SMD route better as it small and compact and does not need any other glue etc.
@@TheEmbeddedHobbyist Hey thanks so much. Would a zero balance point be 0 ohms to the negative terminal of the output. I noticed that on one of the other models that have three pots in about the same place they took the resistor something like 23k to the forth pin over approximately across the opposite side of the circuit board. I may try what you did but I'm a little shaky and in the past I had problems with the SMD getting caught up in the surface tension of the solder and had a hard time keeping it in place while I soldered it. Those are some might fine tweezers! I put on my magnifier head gear and had to use the loop in addition to the magnifier lenses that I think are 2.5x to even get a good look at it ha ha.
Hi Bruce, the resistor was a 24K (2402) 1%. But the pot will allow a small variation in the value, so a 22K or a 27K may still work. The trick is to place the SMD chip where you want it and then solder one end while holding it down with the tweesers. then do the other end, but give the first end time to cool down. The main thing to remember is if you have powered it up give it a while to allow it to discharge the main caps. There are some big value caps in it with rectified mains on them, a sure fire way to ruining your day!
The modification works by changing the ratio of the voltage setting pot. This means the output voltage has to increase to give the correct feedback value. the other video's show what else needs to be done if you need to get to 13.8V or so without the overvoltage trip to kick in. Again be careful these PSU's can kill if you touch the tracks with power on or have not given it long enough time for the caps to fully discharge.
@@ranetti21 this could be caused by tolerances in the components etc. but once you get near to around 13.8V you might need to do the overvoltage mod as well. there is a video for that as well.
Hi! Do you know how to make a HP HSTNS-PC40 PSU work at 13.8V? I only see one potentiometer and turning it does not make a difference in voltage. Thanks.
Sorry not for that PSU, looking at the data sheet it will most likely need to have the over voltage protection upped as well. As the data sheet states that the O/V protection limits are 13.2 to 14.4V. So i expect that it will cut out before it gets to 13..8V. Circuits are hard to find for these PSU's
Hello I have just registered to your channel. Why did you went the hard way. Couldn't you not use the pot to trim the 13,6V. I have the same PSU but I need 14,4V to 14.6V to charge Lifepo4 Batterie to power a smart charger. You have used a 24K resistor to get 13,6V To get 14.4V will the resistor value go up or down. Can you give some advice? Thanks Bob
Hello thanks fo the video my hp1500w power supply heats up quite a bit at 40% load I wanted to know if this is normal? I have other hp1200w power supplies which are much cooler. What is the normal temperature of the power metal cases? Thanks in advance :)
Hi Mehdi, sorry but I can't help with this. This is the only HP PSU I have, and I did the video as I could not find any information on this model. I use the PSU to power a HF Radio where the high current is only pulled for 6 mins max at a time on transmit, so does not get very warm at all. if I can find a cheap 1500W one I may have a look.
@@TheEmbeddedHobbyist Thank you for taking the time to answer me. normally it should be good I check the heat by touching it and it is possible to put my hand between 5 and 10 seconds maximum
very nice... i am going to buy 8 of them from ebay, only 10 dollars each and use it to power an ebike... Gas generator on bike trailer --- > 8 x 12v = 96v --> 96v bldc motor... Do these power supplies work ok on generator power thx...?
I've no idea Nick, they are designed for server power supplies so i expect they would be on a nice stable supply. On a generator you might be pushing the limits of the input circuit.
Hi, I don't have a HSTNS-PL12 so can't help at the moment. but the same process should work with it. but remember these can kill if you touch the wrong place with power on.
Sorry but i never found a circuit diagram for the PSU and did not need to increase the OV protection. so have not looked at that so can't help. i keep lookig for a circuit diagram to do more with this PSU i will do an update.
@@TheEmbeddedHobbyist I installed a 27k resistor, I was able to raise the voltage to 13.7, but I knocked out the overvoltage protection, and I turned the variable resistor on the right in the video, it adjusts the overvoltage protection threshold, and the unit stopped turning on the protection at 13.75 ... it doesn’t work any higher, maybe it will help you change something in the scheme, we need it to be able to charge the batteries, sorry for the Google translator, I am from Ukraine, thank you in advance.
@@avtoelectrik2833 sorry butI have said before, I could not find a circuit diagram for the board and I expected that the over voltage protection is not adjustable so no pot to turn to try and find it. If I ever find it I will post a video on it. I do look every now and then trying to find a fix
Hi, I can't find a circuit digram of the PSU so did look into the OVP as it went to a voltage that I was happy with. Sorry but I'm not into making cahages that might affect the safety without knowing the limitations of the design. my mod did not take the design outside it's limits so was happy it would be safe.
@@TheEmbeddedHobbyist i did voltage upgrade like u but if u turn on the psu and after that connect something when its working like a bulb to check it goes to protection :/ So if ill be working with my car im afraid of unit to shutdown or going to protection doing some manipulations inside car, while flashing or something like that, for example if u turn on ignition and then turn on the psu unit its fine but if u turn on psu and then ignition psu goes to protection, ive tested it on table even with a bulb, and its not even close enough to 60 A.
@@kaprizasds837 Hi, your not the first one to have said this occurs. I will try and look into it but without a circuit diagram it will need to be reversed engineered and I'm not too happy poking around inside with caps charged to 400V. So it may take some time. if you find any other information on these pop back and leave a link.
Bonjour à tous cherche modification pour démarrage alimentation HP HSTNS-PL41 800 watts je ne trouve rien peut etre que quelqu'un à une idée merci amicalement
That's a hard one, did it run on a high power load like lights etc. The problem with RF is it could be getting back down your power leads from the radio and making the overvoltage circuit detect an overload and shutdown. I would try connecting it to a high power DC load to check the PSU can provide the current without a problem, then look at putting someform of choke on the power leads to block RF from getting back to the output of the PSU. You could try and adjust the output voltage a bit lower away from the overvoltage trip point and see if that helps. These PSU were never designed to run near high power RF, so we need to try and protect them from it. Does it do the same thing when the radio is feeding in to a dummy load. So that no RF currents are flowing on the grounds from a mismatched antenna? Just a few pointers as I don't think there is an adjustment that could stop this, apart from lowing the output voltage to give a little more headroom from the overvoltage cutout.
Did a bit more playing with mine to day, and found that it did not like my FT-897. If I connect the FT-897 to the PSU and turn it on the PSU shuts down. Not quite sure what's the cause as this is the only radio it had done that to so far. But I found that the radio started quite happily! So I put a 2 ohm resistor in series with the psu and the radio and a 1000uF cap between the radio and the PSU 0V. This allowed the radio to start up, once running I shorted the 2ohm resistor out. RX current 0.7A 13.6V TX running 100W FM (close to 20A) 13.5V. Radio happy to run in to a dummy load on the PSU at full power. Looks like the PSU might need a big cap on the output for some radios. Looked at the PSU output on start up on my scope and it shows a clean ramp up to 13.6V with no overshoot. FT897 shows a big draw on the PSU on start up, which i don't think the HP PSU likes. Hope this helps a bit more.
looked at mine again and it has issues with my FT897 but only on turn on, which a bit of a Rc filter cleared. see my reply to Sopon above or below depending on where RUclips puts it.
Hi, i've tried hacking my pd29 and failed. After reversing the hack the PSUs voltage is for a very short moment 12v, but it falls to 0v. Is there a way to repair it?
Hi Jan it's hard to say. You just have to go over where you have made the hack and see if there is anything that you have missed when you removed the hack. Look for dry joints or cracks in any SMD components, did you cut any tracks and not solder back over the cuts? Could be that you have upset the overvoltage trip and it's seeing a fault and shutting down. I've never found any circuit diagrams for these server power supplies, and the very high DC voltage puts me off investigating too far.
@@TheEmbeddedHobbyist I poked a bit in the psu, and everything is fine except probably the ovp circuit. Its not that big of a deal since I bought a hstns-pd41 and it seems to be hackable too. Its 2/3 size of a pd29 and a bit more powerful, so the pd29 can stay dead.
Hey, did you came up with any resolution? I have similar case with my PSU. Looks like OVP is always on. With about 20kohm resistor i was able to get 13,7 V easily, but during testing with 200W load it turned off. After removing the mod, PSU works as in your case, the same was when the resistance added was too small (about 10k potentiometer).
@@achimPL Hi, eventually i looked closer and saw that the resistor i soldered to had a burnt contact. After replacing the resistor the psu worked fine. I haven't been able to test max wattage though, because I don't have a load this big. Your case seems to be diffrent though. On my psu I couldn't pull any load since the voltage was visible for not more than a second. In your case you can pull current, but up until a point. This looks like ocp (overcurrent protection) getting triggered. I'd try marking the second potentiometer with a marker, to mark the position and than, try turning it to see if you can get more power
HI, I'm not sure data for these is hard to find, so I coould not say but if you follow the save process it might work. but remember these can kill if you touch the wrong place with power on.
@@TheEmbeddedHobbyist I'm working on the HSTNS-PL28 and the control PCB seems quite different with only 2 adjustment pots. The adjustment (which only goes between about 12.05v and 12.35v) seems to have the +12v output connected directly to the wiper of the pot! So is somewhat different to your design.
@@esuohdica I've only got the one PSU and did find that all those I could find had different PCB layouts. You just need to find a way of making the 12V ouput seen by the pot a bit lower, so it will up the output to compensate. in the end its trial and error, but remember these can Kill easy.
if you mean the HSTNS-PR28-AD 450W PSU i've never looked inside one. I expect that here will be some form of adjustment that can be altered the same way i did for this one.
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
The same method described this video also works for the power supply HSTNS-PD28. Thank`s!
Thanks for the comments, glad i could be of help.
From what I have seen in the past is that when one increases the voltage on these switch mode supplies one must also derate the output amps accordingly.
I would opt to place a small daughter board close to the output leads and allow one to switch between 12.x and 13.x volts, some items don't tolerate 13.8 volts if you plan on using this as a multipurpose supply.
Hi thanks for thge comment. I plan to use this with mobile transivers HF , VHF-UHF etc. 13.8 is the normal battery charging voltage so about what the radio's are expecting to see. I don't think I'll be going too close to the max rated current. max about 30A or 1/2 rated output so should be ok.
One reason for not trying to change the over voltage protection is it should still cut out before it can over voltage my radio's
Great video ! I have resistors that will work but they aren't smd. Can I wire to the leg of the pot you hooked your resistance box to and then take it to ground ? Or do I need to solder the other end to one of the points your soldered the resistor to ? I thought things were small in 1970 when I took a couple electronics classes. A microscope for these old eyes would be handy
the resistors need to go the the same places, except for ground or 0V that end can go to any convenient 0V place. just make sure that the leads and wires are well insulated from the PCB.
Great vid! I have installed 27k smd resistor and range of voltage adjustment was between 13.4 and 13.8V. Best regards!
Hi Janek, you got a higher output than me! Glad it helped.
OVP nie wyłącza tobie przy 50A ? Sam jestem ciekaw tego moda czy warto.
Yes it worked for me. And everybody knows that when we increase voltage to 13.8 the amps decrease a little bit but overall wattage will be same I think there is no issue for components to handle it because its a very little difference between 12v and 13.8v. Nice video
Glad it help.
A great video, thank you! I've just bought one of these on eBay and waiting for it to come in the post. I'm hoping to use it as a current source for vehicle electrical systems when performing software updates to modules when the engine is not running. With the mod in place, do you know what the lowest achievable voltage is using the pot?
Sorry I can't remember, but if you fit a different value for the resistor mod you could tweak it down a bit. Just remember to let the power supply sit for a few minutes after turning off, the high voltage left on the caps inside can easily kill.
@@TheEmbeddedHobbyist thank you for the advice. I will have a play.
What did you use to Energize the unit? I saw you switch it on and off. Or I should say it looked like you switched it on and off. I’ve used a 470 home resistor on mine and I can’t get it to energize. Let me know if you would.
Hi James, My unit has no problems turning on and off! I have a 390 ohm resistor that is switched between the left most track on the top of the PCB and the 4th one in from the left.
why 390 ohms i don't know it must have been sitting on the bench, it's not a normal goto value.
@@TheEmbeddedHobbyist after I spoke to you, I was able to get it energized by shorting the left pens. I’m not sure why the resistor wouldn’t start it. But it’s working now, not with the resistor but by shorting it each time I use it. Thanks for responding. You’re very informative and I will continue watching your channel.
@@Mustang68, thanks
I got the same model PD29
And can energize the unit by short
The left leg and the 4th leg without
Any resistor in between. Question
Is do you really need the 390 ohm resistor ?
Should buy one of these gems for my 3d printer. Is there an application you have in mind, for which 12V is not enough, but 13.8V satisfies?
Yes, 13.8V is the standard voltage for a 12V battery system while being charged. So it the standard input voltage for Ham Radio mobile systems. A 100W HF unit pulls around 20A’s so need a good size power supply. A linear is better option but they tend to be very heavy, so a switch mode is a compromise weight Vs electrical noise. looking at replaceing the 30V 30A variable supply I'm currently using with it for my HF rig,.
@@TheEmbeddedHobbyist Ah yes! Lead acid float-level. (hits head) -- Did not even think of that. May need a current limiting circuit to be safe.
@@GnuReligion I have an old crowbar unit that trips at 14V I was going to put a 30A fuse between the output and the crowbar cct to protect for overvoltage and over current. The psu has overvoltage but you can't be too careful.
Hi .. I trying to get same voltage from the DPS HSTNS -DP19 the circuit board looks similar.. do you know if is the same ..
thank you
No, sorry
@@TheEmbeddedHobbyist thank you anyway..
is there any other way to solder a resistor in that is not an smd resistor. One with a lead say soldering it to the 0 voltage point as others have done on the 4th pin back on the header pins that is 0 volts? I have the stuff but not the practice to solder something that small. that resistor looks like a 2402 24k what size is it?
Hi Bruce, the resistor was a 0806 which just fitted the gap. You could fit a 1/4W resistor between any easy 0V point and straight on to the variable resistor leg or the point highlighted with the resistor in some heat shrink sleeve but I found the SMD route better as it small and compact and does not need any other glue etc.
@@TheEmbeddedHobbyist Hey thanks so much. Would a zero balance point be 0 ohms to the negative terminal of the output. I noticed that on one of the other models that have three pots in about the same place they took the resistor something like 23k to the forth pin over approximately across the opposite side of the circuit board. I may try what you did but I'm a little shaky and in the past I had problems with the SMD getting caught up in the surface tension of the solder and had a hard time keeping it in place while I soldered it. Those are some might fine tweezers! I put on my magnifier head gear and had to use the loop in addition to the magnifier lenses that I think are 2.5x to even get a good look at it ha ha.
One question is, how many ohms is the resistor?
Hi Bruce, the resistor was a 24K (2402) 1%. But the pot will allow a small variation in the value, so a 22K or a 27K may still work.
The trick is to place the SMD chip where you want it and then solder one end while holding it down with the tweesers. then do the other end, but give the first end time to cool down.
The main thing to remember is if you have powered it up give it a while to allow it to discharge the main caps. There are some big value caps in it with rectified mains on them, a sure fire way to ruining your day!
I don't understand, the 24k resistor gets connected to adjustment?
The modification works by changing the ratio of the voltage setting pot. This means the output voltage has to increase to give the correct feedback value. the other video's show what else needs to be done if you need to get to 13.8V or so without the overvoltage trip to kick in.
Again be careful these PSU's can kill if you touch the tracks with power on or have not given it long enough time for the caps to fully discharge.
@@TheEmbeddedHobbyist I've managed to get 13.75v with a 22k resistor
@@ranetti21 this could be caused by tolerances in the components etc. but once you get near to around 13.8V you might need to do the overvoltage mod as well. there is a video for that as well.
Hi! Do you know how to make a HP HSTNS-PC40 PSU work at 13.8V? I only see one potentiometer and turning it does not make a difference in voltage. Thanks.
Sorry Jure, ive not seen that model
do you have any modification of DS1200 EMERSON/ASTEC/ARTESYN to increase voltage to 13.8v ?
Sorry not for that PSU, looking at the data sheet it will most likely need to have the over voltage protection upped as well. As the data sheet states that the O/V protection limits are 13.2 to 14.4V. So i expect that it will cut out before it gets to 13..8V. Circuits are hard to find for these PSU's
Hello I have just registered to your channel. Why did you went the hard way. Couldn't you not use the pot to trim the 13,6V.
I have the same PSU but I need 14,4V to 14.6V to charge Lifepo4 Batterie to power a smart charger. You have used a 24K resistor to get 13,6V
To get 14.4V will the resistor value go up or down. Can you give some advice?
Thanks
Bob
Thanks for subscribing
Normally over voltage protection kicks in above 13.8V. You may have to modify protection circuit as well ... not recommended ;-)
@@danielammann743 do you know how make up ovp ?
Hello thanks fo the video
my hp1500w power supply heats up quite a bit at 40% load
I wanted to know if this is normal?
I have other hp1200w power supplies which are much cooler.
What is the normal temperature of the power metal cases?
Thanks in advance :)
Hi Mehdi, sorry but I can't help with this. This is the only HP PSU I have, and I did the video as I could not find any information on this model. I use the PSU to power a HF Radio where the high current is only pulled for 6 mins max at a time on transmit, so does not get very warm at all.
if I can find a cheap 1500W one I may have a look.
@@TheEmbeddedHobbyist Thank you for taking the time to answer me.
normally it should be good I check the heat by touching it and it is possible to put my hand between 5 and 10 seconds maximum
@@mehdi660 that would put the case at about 60c, as a rule of thumb 60c is about the temperature at which you can just about touch for a few seconds
@@TheEmbeddedHobbyist yes I must surely be in the 60 ° c
very nice... i am going to buy 8 of them from ebay, only 10 dollars each and use it to power an ebike... Gas generator on bike trailer --- > 8 x 12v = 96v --> 96v bldc motor... Do these power supplies work ok on generator power thx...?
I've no idea Nick, they are designed for server power supplies so i expect they would be on a nice stable supply. On a generator you might be pushing the limits of the input circuit.
Do you know how to make HP HSTNS-PL29 work at 13.8V?
I've been watching your video on the boards are different
Not sure of your question, does your HP HSTNS_PL29 have a different board to the one mine had?
@@TheEmbeddedHobbyist yes, i can send you de picture
Can you help me hack model HSTNS-PL12 please thank in advance
Hi, I don't have a HSTNS-PL12 so can't help at the moment. but the same process should work with it. but remember these can kill if you touch the wrong place with power on.
overvoltage protection off? 14v + please help
Sorry but i never found a circuit diagram for the PSU and did not need to increase the OV protection. so have not looked at that so can't help.
i keep lookig for a circuit diagram to do more with this PSU i will do an update.
@@TheEmbeddedHobbyist I installed a 27k resistor, I was able to raise the voltage to 13.7, but I knocked out the overvoltage protection, and I turned the variable resistor on the right in the video, it adjusts the overvoltage protection threshold, and the unit stopped turning on the protection at 13.75 ... it doesn’t work any higher, maybe it will help you change something in the scheme, we need it to be able to charge the batteries, sorry for the Google translator, I am from Ukraine, thank you in advance.
@@avtoelectrik2833 sorry butI have said before, I could not find a circuit diagram for the board and I expected that the over voltage protection is not adjustable so no pot to turn to try and find it. If I ever find it I will post a video on it. I do look every now and then trying to find a fix
Maybe you know about over voltage protection how to remove it?
Hi, I can't find a circuit digram of the PSU so did look into the OVP as it went to a voltage that I was happy with. Sorry but I'm not into making cahages that might affect the safety without knowing the limitations of the design. my mod did not take the design outside it's limits so was happy it would be safe.
@@TheEmbeddedHobbyist i did voltage upgrade like u but if u turn on the psu and after that connect something when its working like a bulb to check it goes to protection :/ So if ill be working with my car im afraid of unit to shutdown or going to protection doing some manipulations inside car, while flashing or something like that, for example if u turn on ignition and then turn on the psu unit its fine but if u turn on psu and then ignition psu goes to protection, ive tested it on table even with a bulb, and its not even close enough to 60 A.
@@kaprizasds837 Hi, your not the first one to have said this occurs. I will try and look into it but without a circuit diagram it will need to be reversed engineered and I'm not too happy poking around inside with caps charged to 400V. So it may take some time. if you find any other information on these pop back and leave a link.
@@TheEmbeddedHobbyist Im trying to find sad about this one psu theres not enough info at all :/ about 800,1200 psus theres kinda lot of info diy.
Bonjour à tous cherche modification pour démarrage alimentation HP HSTNS-PL41 800 watts je ne trouve rien peut etre que quelqu'un à une idée merci amicalement
Désolé, je n'ai aucune information sur l'alimentation HP HSTNS-PL41 800 watts. Bonne chance dans votre recherche.
Any info for the Hstns pl28
Sorry no, info is very hard to find and I just kept finding deadends.
Thanks, it works, but I applied it to the radio, it doesn't work with hi power, it cuts off, what parts do I need to adjust? Thank you in advance
That's a hard one, did it run on a high power load like lights etc. The problem with RF is it could be getting back down your power leads from the radio and making the overvoltage circuit detect an overload and shutdown.
I would try connecting it to a high power DC load to check the PSU can provide the current without a problem, then look at putting someform of choke on the power leads to block RF from getting back to the output of the PSU.
You could try and adjust the output voltage a bit lower away from the overvoltage trip point and see if that helps.
These PSU were never designed to run near high power RF, so we need to try and protect them from it. Does it do the same thing when the radio is feeding in to a dummy load. So that no RF currents are flowing on the grounds from a mismatched antenna?
Just a few pointers as I don't think there is an adjustment that could stop this, apart from lowing the output voltage to give a little more headroom from the overvoltage cutout.
Does the voltage drop when you load the supply using high power? How much does it drop?
Did a bit more playing with mine to day, and found that it did not like my FT-897. If I connect the FT-897 to the PSU and turn it on the PSU shuts down. Not quite sure what's the cause as this is the only radio it had done that to so far.
But I found that the radio started quite happily! So I put a 2 ohm resistor in series with the psu and the radio and a 1000uF cap between the radio and the PSU 0V. This allowed the radio to start up, once running I shorted the 2ohm resistor out. RX current 0.7A 13.6V TX running 100W FM (close to 20A) 13.5V.
Radio happy to run in to a dummy load on the PSU at full power.
Looks like the PSU might need a big cap on the output for some radios.
Looked at the PSU output on start up on my scope and it shows a clean ramp up to 13.6V with no overshoot.
FT897 shows a big draw on the PSU on start up, which i don't think the HP PSU likes.
Hope this helps a bit more.
looked at mine again and it has issues with my FT897 but only on turn on, which a bit of a Rc filter cleared. see my reply to Sopon above or below depending on where RUclips puts it.
Do you know how go up OVP ?
Currently no, as i've not required to do it. the voltage i get out is ok for my needs. So sorry i cant help
What size smd is used please
Physical size
@@davewhitaker I expect it was a 1206 as that was my normal size to use. Worst case it might have been a 0805, no smaller.
Thanks for your quick response 👍
Hi, i've tried hacking my pd29 and failed. After reversing the hack the PSUs voltage is for a very short moment 12v, but it falls to 0v. Is there a way to repair it?
Hi Jan it's hard to say. You just have to go over where you have made the hack and see if there is anything that you have missed when you removed the hack. Look for dry joints or cracks in any SMD components, did you cut any tracks and not solder back over the cuts? Could be that you have upset the overvoltage trip and it's seeing a fault and shutting down. I've never found any circuit diagrams for these server power supplies, and the very high DC voltage puts me off investigating too far.
@@TheEmbeddedHobbyist I poked a bit in the psu, and everything is fine except probably the ovp circuit. Its not that big of a deal since I bought a hstns-pd41 and it seems to be hackable too. Its 2/3 size of a pd29 and a bit more powerful, so the pd29 can stay dead.
@@janmrogJan I expect thats a good plan.
Hey, did you came up with any resolution? I have similar case with my PSU. Looks like OVP is always on. With about 20kohm resistor i was able to get 13,7 V easily, but during testing with 200W load it turned off. After removing the mod, PSU works as in your case, the same was when the resistance added was too small (about 10k potentiometer).
@@achimPL Hi, eventually i looked closer and saw that the resistor i soldered to had a burnt contact. After replacing the resistor the psu worked fine. I haven't been able to test max wattage though, because I don't have a load this big.
Your case seems to be diffrent though. On my psu I couldn't pull any load since the voltage was visible for not more than a second. In your case you can pull current, but up until a point. This looks like ocp (overcurrent protection) getting triggered. I'd try marking the second potentiometer with a marker, to mark the position and than, try turning it to see if you can get more power
I bloody hate that you know what you're talking about. Great vid mr.
Glad you liked it.
Hi would would the mod be the same for the HSTNS-PL29?
HI, I'm not sure data for these is hard to find, so I coould not say but if you follow the save process it might work. but remember these can kill if you touch the wrong place with power on.
Tell me if you have solved the problem. There is no information anywhere on the alteration of HSTNS-PL29
@@TheEmbeddedHobbyist I'm working on the HSTNS-PL28 and the control PCB seems quite different with only 2 adjustment pots. The adjustment (which only goes between about 12.05v and 12.35v) seems to have the +12v output connected directly to the wiper of the pot! So is somewhat different to your design.
@@esuohdica I've only got the one PSU and did find that all those I could find had different PCB layouts. You just need to find a way of making the 12V ouput seen by the pot a bit lower, so it will up the output to compensate. in the end its trial and error, but remember these can Kill easy.
@@TheEmbeddedHobbyist Thanks for the reply!
How to PR 28 ?
if you mean the HSTNS-PR28-AD 450W PSU i've never looked inside one. I expect that here will be some form of adjustment that can be altered the same way i did for this one.
bench show of man