Agilent E3610A -> range switch dont work

[Barny]

Hi

I have the 240V version of the E3610A.
Today i wanted to change from the 15V / 2A range to the 8V / 3A range.
But the display and the output stayed at the high voltage range.
Strange to say is that i am able now to wind the voltage up to 17V.
There is no suspicious smell or visual damage.

Is someone familiar with this kind of error?
Have someone a hint where the error could be?

[sync]

See: https://www.eevblog.com/forum/testgear/calibrate-an-e3611a-and-e3614a-hp-power-supplies/msg642512/#msg642512

[uoficowboy]

Hi

I have the 240V version of the E3610A.
Today i wanted to change from the 15V / 2A range to the 8V / 3A range.
But the display and the output stayed at the high voltage range.
Strange to say is that i am able now to wind the voltage up to 17V.
There is no suspicious smell or visual damage.

Is someone familiar with this kind of error?
Have someone a hint where the error could be?

I had a similar problem on a 120V E3610A. It turned out to be a bad range switch. After cycling it a number of times it got better, but I replaced the switch anyways.

[Barny]

@sync:
The suply stays in both positions in high voltage mod.
At the time I baught it, the maximum was 15.9V, now its 17.4
The low voltage range delivers the same voltage like the high voltage range but the CV and the CC mode LED are in this mide both dark.

I thought this has something to do with the fault.

@uoficowboy:
Thanks for the hint.
I will thake a look.

Was at your suply in the low voltage mode the CV-LED always of too?
Do you have a idea where I could get this rangeswitch?

[sync]

@sync:
The suply stays in both positions in high voltage mod.
At the time I baught it, the maximum was 15.9V, now its 17.4
The low voltage range delivers the same voltage like the high voltage range but the CV and the CC mode LED are in this mide both dark.

My (full working) E3610A goes up to 17.57V in the high voltage mode and the output stays stable at this voltage from 0A to 2.1A (when the current limit kicks in).
On the low voltage mode it depends on the load:
15.5V  no load
13.7V @ 1A
12.5V @ 2A
11.2V @ 3A
And the output is not clean. It has ripple. It's basically unregulated.
On my E3610A (and my actual mains voltage) the low voltage mode is usable up to 10V @ 3A. But HP/Aglient only guarantees that it will work up to 8V. This is how these power supplies are designed.

That both CV and CC LEDs glow can happen when the voltage is set higher that the power supply really can deliver (low voltage mode).

To check your E3610A you should make tests with different loads like above.

[uoficowboy]

@sync:
The suply stays in both positions in high voltage mod.
At the time I baught it, the maximum was 15.9V, now its 17.4
The low voltage range delivers the same voltage like the high voltage range but the CV and the CC mode LED are in this mide both dark.

I thought this has something to do with the fault.

@uoficowboy:
Thanks for the hint.
I will thake a look.

Was at your suply in the low voltage mode the CV-LED always of too?
Do you have a idea where I could get this rangeswitch?

Mouser sells a fairly similar switch, but that's an American distributor. It's a fairly standard part - I suspect you can find a distributor on your side of the big pond. Beep it out with your multimeter - note that it's a DPDT. On mine - only one of the contacts was flaky.

But I'm concerned by the mention of the CV and CI lights being off. Is that true in all modes or only for one position of the switch?

[Barny]

The CV and the CC Led is only of when I switch to low voltage mod.
At high voltage mod everything semms to be allright.

I didnt put load on the low voltage mode since the failure occured to prevent further damage.

At the moment I'm not at home.
I'll measure the switch when I am back.