HP/Agilent E3615A

[rollatorwieltje]

As these can often be found on E-Bay, I thought it was useful to start a topic about these units. I bought mine on E-Bay as well. I guess it's roughly 14 years old, but apart from some dust inside it looks brand new.



Agilent product page:
http://www.home.agilent.com/en/pd-838292-pn-E3615A/60w-power-supply-20v-3a

Quick specs:
20V 3A
Overvoltage cutout
"Programmable" with terminals on the back

The most important thing to note is that these have an input voltage selector switch inside, unlike the E3610A Dave tore down. The cover can easily be removed by lifting the 2 big tabs on the sides. The input voltage can be switched between 100V / 110V / 230V. The switch can be seen on the left side of the transformer. Don't forget to properly mark the set voltage on the back of the unit...



Something funny I noticed is that it's possible to have both the CC and CV LED on at the same time The output is still rock solid when that happens though.

Of course all the components are top of the range. Nice Bourns 10 turn pots, Nichicon caps, decent chassis...

On the back there's a row of switches and connectors for externally setting the voltage and current. External voltage sensing is also supported. When you have another E3615A you can connect them together for all kinds of automatic parallel / serial operation modes.

Be aware that this unit can be damaged when a battery is connected to the outputs and the overvoltage protection kicks in. A crowbar circuit will short the outputs, which is a very bad idea when you have something like a battery or other power source feeding back into the unit.

[neppy5]

Nice write up! I scored one of these on eBay recently and I'm patiently waiting for it to arrive.  Have you played around with the remote control features on the back of the unit?

[georges80]

I've got several E36xx units, one I actually bought and a few freebies from a previous consulting job. They are great units and being fanless they're nice and quiet...

You can never have enough power supplies

cheers,
george.

[dom0]

Something funny I noticed is that it's possible to have both the CC and CV LED on at the same time The output is still rock solid when that happens though.

That's normal and expected behaviour in the CC/CV crossover region.

Contributing to the topic I built a supply similar to a E3630A and I'm very happy with it ; typical HP design with the three S: simple, solid, smart.

[rollatorwieltje]

Nice write up! I scored one of these on eBay recently and I'm patiently waiting for it to arrive.  Have you played around with the remote control features on the back of the unit?

I haven't used them. You can program the voltage and current just like you can with the front panel, that's it. Probably more useful when you use it as a system supply, so you can disable the front controls.

[HighVoltage]

Be aware that this unit can be damaged when a battery is connected to the outputs and the overvoltage protection kicks in. A crowbar circuit will short the outputs, which is a very bad idea when you have something like a battery or other power source feeding back into the unit.

I had to learn this the hard way, many years back!
Magic smoke came out, while a 12 V battery was hooked up.
One large  trace on the bottom of the PCB was burned away and all I needed to do for repair was to add a heavy gauge cable as a trance replacement.

Also on some other HP PSUs, do not hook up a battery and then power cycle the unit.
The crowbar kicks in and smoke will come out.

This is mentioned in the user manual, but I think there should be a big warning label, to make users aware for the crowbar.

[free_electron]

These things use thyristors to create a chopping pre-regulator. The two little yellow tranformers below the big one in the photo are the gate drive transformers.

These supplies use teledyne chips for the displays. They are hard to find but al ost never go bad.

The only problems i have seen with these supplies is the first switch to the right of the power button.It has a white body with a blue plastic cap.

If that switch never is used the co tacts corrode internally and the supply goes all 'weird'.
A good flush with deoxit and vigorously flicking the switch in and out a few dozen times fixes that.