The Poor mans SMU PART 2 - The Agilent 66319D - Page 1
Forum section: electronics / testgear

author: stuartk
author_rank: Regular Contributor
timestamp: May 16, 2016, 04:37:47 pm
content: Following our collective testing of the 66311B, I picked up a few 66319D's at a local auction by complete fluke.The 66319D dual output power supply is the top dog of the Mobile DC source line capable of:• +15 3A output on channel 1• +12v 1.5A output on channel 2• -2A sink capability on channel 1• Built in additional digital voltmeter for checking voltage anywhere in your circuit• Programmable output resistance of -40 Milli-ohms to +1.0000 Ohms on channel 1 to simulate the internal resistance of a battery. Yes not a typo, you can set the resistance to 0.0015 Ohms or 1.5 Milli-ohms for example. As I will show in later posts it becomes useful in the sinking function.It is a 2 quadrant unit capable of sourcing positive output voltage on channel 1 and 2, as well as sinking input on channel 1. This for example allows you to supply output power to your DUT using channel 2 and simulate the main battery of your DUT being charged, by sinking current on channel 1, all at the same time.Keysight Data Sheet is available at the top of this web page:http://www.keysight.com/en/pd-1000000819%3Aepsg%3Apro-pn-66319D/dual-mobile-comm-dc-source-battery-emulation-dvm?cc=US&lc=engI've been playing around with them all weekend and found them very stable and robust. The damn thing is built like a tank to an obvious very high quality standard.Please see the attached teardown photo's for your viewing pleasure. I was only able to remove the case and take some limited pics. I did not remove the circuit boards or connectors for more in depth photo's as I have put these units up for sale and don't wish to damage them.The first photo is a 66311B for comparisonfollowed by a 66319D overview shot.Then note the 66319D extra PCB board. Note the main PCB is now fully populated.Picture of the 66319D transformerand a 0.25 Ohm resistor.Suspect the extra board is for the programmable resistance functionBoard common to all the modelsEnjoy,Stuart

author: nidlaX
author_rank: Frequent Contributor
timestamp: May 16, 2016, 04:56:08 pm
content: Nice one! Do you know what firmware revisions are installed in your units? Also, is that a red X mark on the wide flex cable leading to the interface board?I'm planning on replacing my fan with a San Ace 60 9S type for quieter operation. Hopefully a reduction in airflow from 26 to 20 CFM is still thermally acceptable...

author: nctnico
author_rank: Super Contributor
timestamp: May 16, 2016, 05:09:26 pm
content: Seem like both models use the same PCB layout but with optional components.

author: stuartk
author_rank: Regular Contributor
timestamp: May 16, 2016, 05:23:06 pm
content: Pretty much similar internals with added components.I think the red marking is some sort of blotch or marking from whoever assembled it.Here is the ROM version:Here is my test setup. In this picture, the DP832A is set to output a CC of +1A and the 66319D has it's internal resistance set to 500 Milli-ohms sinking the 1 amp, resulting in surprise surprise a voltage of 0.5 volts!I used this silent Vantec fan purchased from Newegg, seems to work fine even after 20 min of full load.

author: TheSteve
author_rank: Unknown
timestamp: May 16, 2016, 05:59:47 pm
content: Thanks for the pics. An amazing amount of hardware inside these things. If you get a chance please dump the firmware.I still use my 66311B all the time.

author: stuartk
author_rank: Regular Contributor
timestamp: May 16, 2016, 06:26:32 pm
content: Hi Steve, yep they are really good units.Here are some more pics:66319D Output channel 1 at 15v no loadOutput channel 2 at 12v no loadOutput at 3A full load channel 1 (fan going at full bore)

author: stuartk
author_rank: Regular Contributor
timestamp: May 19, 2016, 11:46:29 pm
content: Some more pictures of the 66319D:Here is a shot of the auxiliary 3rd channel DVM in action:Setting the current range to 20mA:Driving a small LED at 1.8v:You can see the LED at the top of the picture:

author: stuartk
author_rank: Regular Contributor
timestamp: May 20, 2016, 12:05:43 am
content: And lastly, the sinking function on channel 1. To use it, set the voltage to zero volts on channel 1 and then turn the output on.If you keep the resistance at zero, it will sink up to -3A prior to the protect function engaging. Setting the resistance to its maximum at 1 ohm, it will sink up to -2ASinking 3A at o ohms:Setting resistance to 0.2000 ohms0.6 volts as expectedSinking 1 amp at 0.5000 ohms gives 0.5 volts as expectedSinking 1.5A at 1ohm again demonstrates ohms lawWell that's it for me,Cheers to all,Stuart

author: vaualbus
author_rank: Frequent Contributor
timestamp: May 29, 2025, 08:43:27 am
content: Old thread but maybe can help me on a thing I obversed.Can anyone measure the output resistance of the output 1 when the device had the output set to off?I never measured it before but yesterday I found I have around 90ohm between the output + and GND when the supply is on and its output is disabled.On my 66309D I have ~500k but that's ok because I have option 521, has mechanical relay for disconnect the output, and what I read is within the spec of the supply.No idea on what happen on supply without the 521 option.So, I am curious If I have blown an output transistor or is normale such "low" resistance.The supply nonetheless regulated the voltage and current correctly when the output is enabledThanks to anyone that can "help" me on this!