HP E3610A power supply (Solved)

[Remy]

Hello, happy new years to everybody
As y am french, so excuse me for my bad english 

Y try to repair Hp E3610, but i dont find solution. Y have only fluke multimeter  , no scope
potientiometer are both in maximun (current an voltage).

Pb : when I switch range (8v to 15V) nothing happend. Output stay at about 15V all time.
Y check all alimentation test point an it is ok (TP 9, 1, 5, 8 ) .
The only change is Tp2 moving up from 16.5V to 26.4V.
So, y change U4 (double op amp) but it is the same. Output of this op stay stable    . I make mesurement at Tp7 an y have -4.75 / -3.25 for range 8 /15.

Is there someone find this on this type of equipement?
Thank you for your help
Regards
Rémy

[wn1fju]

The HP E361x power supplies have known problems with the electrolytic capacitors.  Whether it is a thermal problem (some are near the warm main transformer) or a poor design (insufficient ripple current capability), they tend to leak electrolyte which creates havoc on the main board. 

I suggest you pull all the electrolytic capacitors and check for wet electrolyte underneath.  Scrub the board with alcohol thoroughly before you replace or reinstall any capacitors.  I assume you have some way to test the capacitors with your DMM.

This may or may not be what is causing your problem, but it is worth doing anyway.  On my HP E3611A, I saw leaking electrolyte near a few caps, so I replaced those.  A few months later, the unit malfunctioned and it was due to leaks underneath the capacitors that I didn't originally pull.

[Remy]

thanks for your answer.

I replace all the electrolytic capacitor by new part, and clean printed board before soldering them.
but  power supply does not go on. Same problem than before.
Y dont really know what to do and it is difficult to understand schematic and how does it work.
Y read some post on this forum about E36xx, but y dont find same problem and how to resolve it  .

[free_electron]

depending on the age of the machine there are variants. you may  need to install the bleed resistor

https://siliconvalleygarage.blogspot.com/p/e3610a-e3611a-e3612a-e3614a-e3615a.html

And cleaning off capacitor electrolyte needs to be done with vinegar, followed by a 50/50 mix of distilled water and IPA ( isopropylalcohol). There are different kinds of electrolyte. some are water based, some are alkaline ( the older ones). the vinegar bath makes sure the older types are neutralised.

[Remy]

Good morning,

some news from my E3610 power supply.

After applying all recommended changes (thank you to "Free_electron" for the link), range switching still does not work (8v/ 15v).
The list of amendments is as follows:
_replacement of all electrochemical capacitors
_Suppress C5 and C4
_Replace C12 with 470uf 50v
_installed resistance R 46 (bleed resistor)
_installed capacity 220pf paralel on R6

Then check the voltages at the different test points and everything seems OK (+12V, +5V _1, +5V_2, -12V,  and V Tp2)  .  Note that V Tp2 changes well when you switch the range!

As the output voltage still does not switch according to the range, replacement of integrated circuits U1, U4, U5.
The range control still doesn’t work!!!

 Then I also checked Q2 and the transistor works (hfe = 50).

Here’s where I am and I don’t know what to do  . If you have an opinion on this strange breakdown, I would very much appreciate your help.

Thank you
Remy

[free_electron]

Wait a second. I think you misunderstand these supplies

This is essentially a supply that can give "up to 15 volts at 2 ampere" under all conditions. When you want more current you can get 3 ampere at up to 8 volts.

This is NOT a range switch. The output voltage does not magically double. It is a power dissipation limit to protect the power transistors in the supply. It simply makes sure you don't drive them in thermal overload. They did this to be able to use a small heatsink.
That range switch is essentially a power dissipation limit switch. This supply is made for 30 watts.

[wn1fju]

Yes, free_electron is exactly correct.  I am embarrassed that I didn't also catch the original poster's mistake.  I should have known better especially since I have one of these power supplies.

[Remy]

Good morning,
and thank you for your answers.

To be sure i understand, the 8v/15/ switch is not a choice of range, but only a choice of available current (or max power)  .

So, if I am on the 8V position, it means that I can have a 12V voltage output if the current is low (example 1A with 12 load).
If I change load to have a current of 2.5A (3 ), then yes, I could not have more than 8V on the output but current will be ok.
This is how this supply works, right or not ?

Thank you for coming back and for taking  time to explain me how it works.
Rémy

[free_electron]

correct. The supply can give you 15 volt at 2 ampere max. If you stay below 8 volt you can push the button and get up to 3 ampere. Even though the supply can give more voltage on this range , the regulation and output voltage is not guaranteed. It will regulate current BEFORE voltage ( traditional current limiting mechanism. )

For light loads you will be able to get higher voltage in the 8v range but the supply will regulate back if you ask for higher voltage.

[Remy]

Thank you very much for your answer 
I now better understand how this power supply works.
I’ll be able to use it properly 
cordially
Remi

[jonpaul]

Bonjour cher Remy, bravo pour le intéressant question

Les alimentation marque HP il ya le plus qualité

J'habite Paris 6eme

Peut-être nous pouvons appeler ou RDV quelques temps

Amicalement

Jon

[Remy]

Good evening,

I reassembled the power supply and performed  differents tests with a variable resistive load.
Everything is fine and the power is working properly. 

thanks for your help.
Rémy

Pour Jonpaul, regarde le message personnel 

[fmashockie]

Just wanted to add this here.  I recently repaired a HP E3612A which is practically the same as the E3610A except it has max voltages of 60V and 120V and 0.5A and 0.25A, respectively.  The problem with this one had to do with faulty current control.  It would only limit current to 60mA regardless of what the setting was.  Also, the max current could only be set to ~280mA.  I traced both these problems to a dirty CC set button (cleaned with contact cleaner) and a faulty Q5 2N2222.  I did a video on my YT channel walking through troubleshooting and repair.  Hopefully someone can find this helpful!