troubleshooting: Agilent 3616A power supply

[Cydrome Leader]

I'm only asking as maybe this is a common failure mode somebody has seen.

Got an actual Agilent badged 3616A power supply, one of the half-rack
width deals with the LED voltage and current display and a single 36volt
1.6A output.

Out of the blue, the current meter seems to read strange phantom currents
that decrease slowly, like you're charging a large capacitor. It also
seems to have a lag when measuring real currents. The lag is at least
several seconds.

I just recall this thing being a hassle to work on before. Opened it once
to swap power receptacles because of the shock hazard recall.

If not, I'll report back with what I find at some point.

 

[Winfield Hill]

Cydrome Leader wrote...

I'm only asking ...

Got an actual Agilent badged 3616A power supply ...

That set of HP's half-rack series of power supplies
is actually easy to work on, IF you have a schematic.

But the schematics that I've seen don't detail the
3.5-digit panel-meter wiring. If the problem is
simply a matter of faulty readout, and the supply is
working properly, then you have a bad DVM IC circuit.
Get the ADC-display-driver IC's part number, and its
datasheet will show typical wiring. Either there's
a wiring failure (connector) or a bad IC.


--
Thanks,
- Win

 

[Cydrome Leader]

Winfield Hill <hill@rowland.harvard.edu> wrote:

Cydrome Leader wrote...

I'm only asking ...

Got an actual Agilent badged 3616A power supply ...

That set of HP's half-rack series of power supplies
is actually easy to work on, IF you have a schematic.

But the schematics that I've seen don't detail the
3.5-digit panel-meter wiring. If the problem is
simply a matter of faulty readout, and the supply is
working properly, then you have a bad DVM IC circuit.
Get the ADC-display-driver IC's part number, and its
datasheet will show typical wiring. Either there's
a wiring failure (connector) or a bad IC.

Well heck, that was easy.

Disconnecting and reconnecting the 11 pin connector between the board and
display seems to have "fixed" it. I did run through the calibration steps
in the Agilent

E361xA 60W BENCH SERIES DC POWER SUPPLIES
OPERATING AND SERVICE MANUAL FOR MODELS: (bunch of serial numbers)

It was necessary to pry the double stack PCB display board out of the
front panel. It's two plastic tabs you can sort of get to from the top
of the power supply if you slip the cover off. Gently press those, and
wiggle the display board out by pulling on the sides.

Oddly, only needed a spudger and fine screwdriver for adjusting some mini
10 turn Bourns pots. The design is nicer than I recalled, and the mostly
tool-free design reminds me of Motorola back when they were in business
and made good radios and cell phones.

Writing inside the cover indicates I replaced the AC receptable in 2008.

Any opinions on "keysight" design, build or service since the rename?

 

[legg]

On Tue, 21 May 2019 03:25:02 +0000 (UTC), Cydrome Leader
<presence@MUNGEpanix.com> wrote:

Winfield Hill <hill@rowland.harvard.edu> wrote:
Cydrome Leader wrote...

I'm only asking ...

Got an actual Agilent badged 3616A power supply ...

That set of HP's half-rack series of power supplies
is actually easy to work on, IF you have a schematic.

But the schematics that I've seen don't detail the
3.5-digit panel-meter wiring. If the problem is
simply a matter of faulty readout, and the supply is
working properly, then you have a bad DVM IC circuit.
Get the ADC-display-driver IC's part number, and its
datasheet will show typical wiring. Either there's
a wiring failure (connector) or a bad IC.

Well heck, that was easy.

Disconnecting and reconnecting the 11 pin connector between the board and
display seems to have "fixed" it. I did run through the calibration steps
in the Agilent

E361xA 60W BENCH SERIES DC POWER SUPPLIES
OPERATING AND SERVICE MANUAL FOR MODELS: (bunch of serial numbers)

It was necessary to pry the double stack PCB display board out of the
front panel. It's two plastic tabs you can sort of get to from the top
of the power supply if you slip the cover off. Gently press those, and
wiggle the display board out by pulling on the sides.

Oddly, only needed a spudger and fine screwdriver for adjusting some mini
10 turn Bourns pots. The design is nicer than I recalled, and the mostly
tool-free design reminds me of Motorola back when they were in business
and made good radios and cell phones.

Writing inside the cover indicates I replaced the AC receptable in 2008.

Any opinions on "keysight" design, build or service since the rename?

Service policy depends on model number. info on website.

For data loggers it invlolves a complete swap +$ ~retail cost of an
uncallibrated replacement. . . .

So you might as well fix it and get a local lab to calibrate, if you
need traceability.

RL