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Bad P6KE150A Transient Voltage Suppressor Diode In HP Power Adapter

By on February 10, 2017
test p6ke150a transcient diode











Normally we call our articles a repair when we add or replace a component in a device to make it work. However the device in this repair did work by just REMOVING one single component!, so I maybe better call this article a Fix instead?

But let us start from the beginning. I found a used LCD Monitor at the Dump in my neighbourhood, a FLAT PRO_ MEDION Monitor. They had removed the Screws and its Stand. So I mounted another heavy Alu Metal Stand I had saved from an old disassembled Monitor. And it had no 19V 2.5A Power Adapter either. Therefore I used an old HP Power Adapter to test it which worked great although the Adapter only was designed for 18V 1.1A, thinking it wouldn’t really matter because often the given Amperage is higher than the real Amperage. And since the Monitor worked without any problem whatsoever I put it aside for another occasion.

And yesterday I quickly needed a Monitor to test and install my friend’s 2 desktop computers. Why I used the Medion LCD Monitor and the HP Adapter (a HP AC POWER to DC C6409-60014 Adapter).

hp adapter repair

But after about less than a half hour or so the Monitor screen went blank. And after measuring the DC Adapter output it was obvious that only 2.5V DC never would work. So I continued my work on my friend’s PCs after attaching my Medion Monitor to my +30V 10A DC adjustable Wanptek KPS3010D. This little adjustable but great DC power supply unit was also mentioned in one of my previous Laptop repairs.

The Monitor needed 2.49A at 19V according to the display of the PS3010D. So my HP Power Adapter (previous for a Printer Power Supply) was working too hard and finally had quit on me! Removing the 3 screws to open the Adapter was easily possible after pinching through the bottom Sticker/Label. The now defect HP printer AC-DC Adapter would have to wait for another moment after I first had fixed my friend’s little PC problems. Below is the Monitor and the KPS3010D.

fix hp adapter

And today I opened the 18V 1.1A HP Power Adapter to investigate further. I couldn’t find anything wrong with the secondary Dual Diode, the Primary Diode Bridge, The Fuse, or the Power Transistor a Toshiba K2545 Silicon N Channel V-Mosfet . Everything was okay. Following photos show the inside of this service friendly made Adapter.

how to fix hp power adapter

dap001 power ic controller

k2545 power fet

Previous photos showed the DAP 001 controller from STMicroelectronics / Heisener electronics that was not burned either. And the Toshiba K2545 Silicon N Channel V-Mosfet. And all Diodes and resistors were fine, except ZD1 that had a resistance of 24 ohm in both directions. And after I removed it from the PCB and tested it with my fast and great working PEAK DCA Pro 75 tester (that operates on a cheap and simple single AAA battery!), The Display showed ‘No Component detected’.

The ZD1 Diode with P6KE150A marking was a 600W Suppressor diode from Littlefuse. And I decided to remove it because the reason for activating this protector Diode was now disconnected (which was removing the Monitor from the adapter) and there were no other faults. I also used my Blue ESR Tester to measure the ZD1 resistance in both directions. It was 19 Ohm.

So because nothing else seemed broken, burned or short circuited I used the Light Bulb trick to see if the HP Adapter would work again after having removed this Littlefuse suppressor Diode.

And it did! Following photos show the 18.35 V output that was restored! And I have said it probably often before that the repair did cost almost nothing. But in this case I didn’t even need a new component to make the Adapter work again! (Of course I must buy a Littlefuse suppressor Diode P6KE150A for Safety reasons, but since the Power supply also has a Primary Fuse for protection and it already works again, it only protects in case of any overvoltage). Next photos show the defect ZD1 protection Diode and the PCB bottom where the diode was removed.

And the last photo shows the Fixed Power Supply.

p6ke150a transcient diode

bad p6ke150a transcient diode

testing p6ke150a transcient diode

The removed Suppressor Diode is much faster than VDRs that are also used in Power Supplies for the same prevention. It short circuits any Overvoltage momentary within 1.0 ms or even in Pico seconds to protect the Circuit on the contacts that the Diode is attached to. These Suppressor Diodes are also called TVS Diodes, Transorbs, Transient Voltage Suppressors or Thyrector Diodes.

In case of this P6KE150A the Peak Current (IPPM) is only 2.9A which is about a tenth of the value of a P6KE15A Diode which is 28A. This is related to the Breakdown Voltage that is much lower for the P6KE15A Diode. And the Maximum dissipation is for all P6KExxx components always 5W. And Power = Voltage multiplied by Current. The Breakdown Voltage of the destroyed P6KE150A in the HP Adapter is min 143V and max 158V. And the Clamping Voltage is 207V.

In the HP Adapter the Diode was destroyed which means that it is used beyond the specs that it was designed for. So it normally would survive a big (600 Watt !) short overvoltage spark. Suppressor Diodes that are destroyed can end as Shorting Diode, Open Diode, or as degraded Diode. And in all cases the TVS Diode must be replaced for safety reasons. Such a diode exists in fact out of two special diodes in antiserie (opposing positions of both avalanche Diodes) connected together and placed in a single Diode housing.

There are also TVS Diodes that rectify in one direction and overvoltage suppress in the other. This Internet Link gives more useful information about them:

Especially the Characterics of the TVS Diodes are here very well explained!

TVS Suppressor Diodes are still seldom used in circuits built by amateurs but could easily prevent the destroying of expensive Semiconductors. Like this article proves because all other parts including the Semiconductors are still fine after the overvoltage power surge.

And since the P6KE150A TVS Diode used in the HP Adapter of this ‘repair’ only costs $1.60 dollar when 20 pieces are ordered at Free Shipping, it would be just stupid not to replace it. Safety First at all times is the smartest thing to do!

Albert van Bemmelen, Weert, The Netherlands.

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Note: You can read his previous repair article in the below link:




  1. Anthony

    February 10, 2017 at 4:33 pm

    Hi Albert, nice repair and very economical to replace the faulty diode
    for that price ! Maybe you could "bill" your local power company for
    their failure in not providing a clean supply and present them with an
    invoice for $1.60 plus labour costs! Haha...Well done

    Kind Regards

  2. Paris Azis

    February 10, 2017 at 7:56 pm

    Good job, Albert

    I fully agree with the last paragraph of your text!
    The prevailing factor over a repair should not be it's cost but it's quality instead.
    At least the circuit should remain as designed, meaning not being degraded by repairing it.
    It's all a matter of attitude...

    • Albert van Bemmelen

      February 10, 2017 at 9:26 pm

      Totally true Paris! We do not want to grab an old piece of equipment that is defect or unsafe when we need it. Besides next time we could have forgotten what the complaint of the bad working Device was. Certainly not if it carries our own repair signature!
      Sorry if my reply to Anthony's is somehow changed in chronological sequence with yours! Do not know why that happened.

  3. Albert van Bemmelen

    February 10, 2017 at 8:09 pm

    I am not sure if it was the power company that caused the TVS Diode to collapse, Anthony. To be sure of that I would have to repeat my setup being attached to the Monitor while measuring the voltage over the Diode. I do not have another P6KE150 Diode to find this out yet. Or I could draw a circuit plan of the HP Printer Power Supply that would show how the special Transformer is connected to all other parts, including the TVS Diode. Because I think it had a big part in protecting the Semiconductors in this Supply. But anyhow I do not think the power company would care very much what it did cost or how I spend my freetime.

    • Anthony

      February 11, 2017 at 4:08 am

      Hi Albert, not sure if your electrity supplier is government or privately operated but if it is the latter then they rarely
      do much in the way of preventative maintenance as to maximise their operating profits. This can lead lead to all
      sorts of issues and may have contributed to the faulty TVS diode you located. I'm not saying it was definitely the
      cause of the problem but power surges, spikes are nasties that can play their part for causing power supply
      failures. I now have all my devices plugged into surge protectors as insurance companies often won't pay out
      on these damaged items. Just an idea Mr Albert but I certainly respect your better knowledge on these issues.

      Best Regards

      • Albert van Bemmelen

        February 12, 2017 at 2:20 am

        I also protect most of my expensive devices by using a BELKIN Surgemaster, Anthony. But I still could use an extra couple of them in my other rooms.

        I once heard of a disaster that happened in the nearby Flat/appartments after Lightning had struck into people's homes through the TV Ground Cable, and had destroyed all their appliances like Washing machines, Television sets etc.etc.

        It is like they say "Better Safe than Sorry!".

  4. mahmoud_tajpour

    February 11, 2017 at 4:40 am

    hello dear Albert good job i enjoy of your good repair.

    • Albert van Bemmelen

      February 11, 2017 at 3:13 pm

      Thank you Mahmoud, glad you liked it. After the new ordered TVS Diodes are received, one P6KE150 Diode will be added to the HP Adapter circuit again of course.
      And the article explains the most important things to know about these TVS suppressor Diodes and why they collapse.

  5. suraga Electronics

    February 11, 2017 at 6:28 pm

    Hi Mr Albert ,

    Easy and good repair job.
    I have repair before this same fault.

    Thanks !

    • Albert van Bemmelen

      February 12, 2017 at 2:25 am

      Thank you Mr.Sura(n)ga! (;)
      If it are not the E-Caps that cause problems, we now have failing Suppressor Diodes too.

  6. Joop

    February 11, 2017 at 10:23 pm

    Thank you Albert.
    I always read your repair articles and i can learn a lot of you.

  7. Parasuraman S

    February 12, 2017 at 1:32 am

    Great informative article, indeed! A lot of stuff to learn! Many thanks for your article!

    • Albert van Bemmelen

      February 12, 2017 at 7:55 pm

      Datasheet information always helps a lot. Thank you Parasuraman S. But the information also informs us that we still do have to buy other Suppressor Diodes for other voltages too. But as they say: every advantage has its disadvantage. (;)

  8. Albert van Bemmelen

    February 12, 2017 at 2:28 am

    I am very glad that my little contributions are appreciated Joop!

  9. Mark

    February 12, 2017 at 1:19 pm

    Hey Albert,

    Great to see the protection systems working. They are a lot cheaper and easier to replace when they do their job! I didn't know that Suppressor Diodes are faster than VDRs. I'll have to keep that in mind during my next build.

  10. Albert van Bemmelen

    February 12, 2017 at 7:57 pm

    I've never used Suppressor Diodes before myself Mark, but this article kind of introduced me to start using them.

  11. Ulises Aguilar Pazzani

    February 13, 2017 at 2:21 am

    MR van Bemmelen, greate fix

    • Albert van Bemmelen

      February 14, 2017 at 1:43 am

      Thank you Ulises. It was a small fix but with great effect.

  12. Yogesh Panchal

    February 13, 2017 at 2:57 pm

    Thanks for sharing your Experience with TVS Diode.
    what you think about "ZD1" resistance in both directions that is 19 Ohm.seems like Leakey;is that because of circuit design problem or component it self end to the life.

  13. Albert van Bemmelen

    February 14, 2017 at 1:50 am

    It is because Yogesh, as I also wrote in the article, caused by a collapsing TVS Diode that couldn't handle the momentary overvoltage. And therefore was destroyed and normally would have survived a very short 600 Watt Power Spike.
    And when this happens they end as an open Diode, or as a shorting one. Or can even become out of spec.

  14. Robert Calk

    February 14, 2017 at 8:20 pm

    Good job, Albert. I agree - safety first.

    • Albert van Bemmelen

      February 18, 2017 at 4:13 am

      Yes indeed Robert. In electronics we often get only one chance to do it right!
      Any other way results in semiconductor electron avalanches, burnt copper tracks or exploding e-caps.

  15. Mahmoud

    February 19, 2017 at 4:11 pm

    good job well done

    • Albert van Bemmelen

      February 24, 2017 at 7:40 am

      Thank you Mahmoud.

  16. Nihat Zyulkyarov

    January 20, 2021 at 8:40 pm

    Hello Albert,

    I have the absolutely same HP Adapter and it has failed also.
    Few days ago i opened it and found that the fuse F1 at very beginning near to 220V input (3.15A/250V) has burned (measured) and i decided to replace it for testing only with a tinny wire ~0.3mm..
    When i plug the 220V power on i received a big BUMMM! and found that the biggest size capacitor C1 - 68uF/400V (near to diode you changed) has literally exploded.
    Then i found your blog and read what you have done! I measured my diodes, resistors and K2545 , but cannot found any failure.
    So would like to ask you as well as others here what could be the issue in my case ? what to measure or test next?
    I am not sure how to measure DAP 001 controller if it is OK or not ?
    In my case ZD1 Diode is OK according to my multimeter.

    Thanks in advance !

    • Albert van Bemmelen

      January 22, 2021 at 2:33 am

      I am afraid that when you tested the adapter without a safety light bulb to protect a big short circuit current from happening it now destroyed your controller and the e-cap. That created the big BOOM!
      I am not sure if these parts are available. If your device no longer is fixable not at best use or buy another power supply and if possible exchange the power cords so the fit again. Instead of a thin 03 mm 'fuse'wire you should have used a safety light bulb to protect the parts from overcurrent. Hope this helps you to find a solution.

      • Nihat Zyulkyarov

        January 22, 2021 at 9:44 pm

        Thank you !

        In future i will know that i should use a safety light bulb serial connected when i am repairing something!

        Thank you very much again !

  17. Albert van Bemmelen

    January 22, 2021 at 2:37 am

    I noticed some typos in above post, meant to write : if no longer fixable NOW at best use or buy... , exchange the power cords so THEY fit again. (Sorry...old keyboard and big fingers). Good luck in fixing your power supply!


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