My poor mans SMU - The Agilent 66311B

[TheSteve]

OK, perhaps it isn't really an SMU, its certainly not 4 quadrant, but its still darn cool for the price. The Agilent 66311B Mobile Communication DC Source supplies 0 - 15 volts at up to 3 amps and can sink 0-15 volts at up to 2 amps. It also has the expected CV and CC modes, OVP, OCP, output on/off and lots of other goodies including serial and GPIB interfaces. There is some very nice software for it that I don't even want to know the price of. It looks pretty unassuming but is 18 inches deep and weighs over 9 kilos(20 pounds). Programming accuracy is 0.05% + 10mV for voltage and 0.05% + 1.33 mA for current. DC measurement accuracy is 0.03% + 5mV - the current spec are pretty darn good as well. The data sheet on the whole series can be found here:
http://www.keysight.com/upload/cmc_upload/All/66300series_datasheet_Jan07.pdf

I picked this unit off ebay for a best offer of 55 USD (and 35 for fedex ground shipping) in the usual "has errors, not working etc" state. When I received it I powered it up and it randomly gave me every error documented in the service manual. At first I thought maybe something was loose as errors are not generally that random. Then I had better look at it and noticed it said 220 VAC on the back. A read through a service note indicated they are all shipped for 220 VAC operation but can be jumpered to 120 VAC etc. Sure enough it was jumpered to 220 VAC. To configure it for 120 VAC it requires an extra jumper. Agilent was nice enough to provide the spare jumper - it is connected to unused lugs on the transformer. Once reconfigured it powered up without error and is working perfectly. The calibration looks great - everything checks out bang on with my new 34461A. The build quality looks very nice inside, Agilent didn't cheap out at all. It uses a connector on the back for power out and has sense lines to compensate for voltage drop. There is also a version with front mounted banana jacks - a quick look at the front panel shows the plastic is molded to accept two banana jacks so mine will likely get modified with a pair pretty quick. I'll jumper the sense line to the jacks which should be good enough for my use.

The seller has more of them, no idea if some have real faults or if they are all simply configured for 220 VAC.  I have NO connection to the seller, I just like what I got for 90 USD shipped.  # 281926297815 for those who want to try their luck - maybe someone can get them to accept an even lower best offer.

[TiN]

That's some real transformer beef. How about more detailed PCB shots?

[TheSteve]

That's some real transformer beef. How about more detailed PCB shots?

Absolutely!

[TheSteve]

more pics

[TheSteve]

And the transformer which has a total of 20 spade lugs coming out of it.

[crispy_tofu]

Wow, looks like a nice piece of kit! 

[nctnico]

How if the fan noise of this thing? Is the fan always on or is it temperature controlled? HP/Agilent had a habit of not caring much about fan noise.

[gslick]

I have some 66309D versions. I'd have to check the specs to see exactly how they differ from the 66311B. The 66309D is dual output, and the 66309D vs. the 66309B also has built-in DVM capability (with some limitations on range relative to the outputs).

The fan is always on, but it ramps up and down depending on the load. You definitely hear the fan even when not loaded.

They are surprisingly heavy for their size.

[PA0PBZ]

The seller has more of them, no idea if some have real faults or if they are all simply configured for 220 VAC.  I have NO connection to the seller, I just like what I got for 90 USD shipped.  # 281926297815 for those who want to try their luck - maybe someone can get them to accept an even lower best offer.

The global shipping program alone takes $90 from me, so I'll pass this time.

[nctnico]

Now I'm tempted and I've got to have one if the price is right! 

edit: shippings costs are high indeed...

[HighVoltage]

The front and inside look very similar to the 6612C, just without the front binding post.
And the 6612C is much much more expensive.

Thanks for sharing the 66311B, I was not aware of this model.

[michaeliv]

[...] and can sink 0-15 volts at up to 2 amps. It also has the expected CV and CC modes [...]

Manual says that it doesn't have CC sink capabilities. How does the sink feature actually work ? Does it actually display the real voltage when sinking ?

[gslick]

[...] and can sink 0-15 volts at up to 2 amps. It also has the expected CV and CC modes [...]

Manual says that it doesn't have CC sink capabilities. How does the sink feature actually work ? Does it actually display the real voltage when sinking ?

I just tried this with a 66309D with its output 1 connected to the output of a 6632B (0-20V, 0-5A). When the 6632B is programmed for a higher output voltage than the 66309D the 66309D will sink as much current as it is capable of doing while displaying the measured voltage at its output and the measured current that it is sinking. As long as the programmed current limit of the 6632B is within the current sinking capability of the 66309D the 6632B will be in CC mode and the voltage measured and displayed by both the 66309D the 6632B will be very close to the voltage programmed into the 66309D.

Figure 2-1. Dc Source Output 1 Characteristic in the manual shows the current sinking capability of approximately 2.8A at a programmed voltage of 0 volts dropping to a current sinking capability of approximately 1.2A at 15 volts. With the 66309D programmed for 0 volts I didn't see the UNR indicator turn on until the 6632B was set for closer to 3A, and when with the 66309D programmed for 15 volts I didn't see the UNR indicator turn on until the 6632B was set for closer to 1.6A. I didn't want to experiment too much with the 66309D current beyond the ranges specified in the manual.

In contrast the negative current sinking setting of the 6632B is programmable as the same setting as the positive current sourcing.

Agilent Part No. 5964-8125
USER’S GUIDE
Agilent Model 66111A
Fast Transient DC Source
Agilent Model 66311B/D, 66309B/D
Mobile Communications DC Source

Output 1 Characteristic

Figure 2-1 also shows a single range ? two quadrant capability. This means that the dc source is capable
of sourcing as well as sinking current over the output voltage range from zero volts to the rated voltage.
This negative current sinking capability provides fast downprogramming of the output of the dc source. It
can also be used to sink current from a battery charger, thus providing battery charger test capability. The
negative current is not programmable, and varies linearly from approximately 1.2 amperes at the full
rated voltage, to approximately 2.8 amperes at zero output voltage.

NOTE: If you attempt to operate the dc source beyond its output ratings, the output of the unit
may become unregulated. This is indicated by the UNR annunciator on the front panel.
The output may also become unregulated if the ac line voltage drops below the minimum
rating specified in Appendix A.

[ve7xen]

Pulled the trigger on a $55 offer that was accepted. Thanks for the heads up!

Definitely want to do the front-panel binding posts mod, if my unit works. Anyone know of a good quality suitable type for this?

[nctnico]

$55 seems to be the magic number the seller is looking for indeed. I bought one as well 

[ThomasDK]

That's some real transformer beef. How about more detailed PCB shots?

Absolutely!

Interesting to see a DSP in a power supply. What was the original purpose of these supplies?

Thomas

[TheSteve]

Pulled the trigger on a $55 offer that was accepted. Thanks for the heads up!

Definitely want to do the front-panel binding posts mod, if my unit works. Anyone know of a good quality suitable type for this?

The Agilent variation uses a PCB but I am thinking the right posts will fit without too much effort. The holes are covered over only by the front label. I'll try to get some pics/measurements tonight or this weekend. The mounting portion of the post may need to be longer then normal because of how the plastic is molded.

[TheSteve]

That's some real transformer beef. How about more detailed PCB shots?

Absolutely!

Interesting to see a DSP in a power supply. What was the original purpose of these supplies?

Thomas

They were intended to be used to characterize the power usage of mobile devices such as cellphones. There are variations of the supply that have dual outputs so you can power the phone with one supply and simulate the battery(charge and discharge) with the second supply.

[Muxr]

Hey, thanks for the tip. I picked one up as well. Will report once I get it.

[nctnico]

Another question: which type of plug is used for the output so I can order a replacement? I guess it will be missing...

[TheSteve]

The Agilent part # is 0360-2604
A google search indicates someone suggesting a Phoenix Contact 1757048 but that is not confirmed.
I see people also have them on ebay but they never seem to post the part #
I am using alligator clips at the moment.

[nctnico]

It looks like a standard Phoenix plug but it would be nice to know the exact pitch (5mm or 5.08mm).

[Muxr]

Man their website is pretty unintuitive. There is no easy way to get to the shopping cart. They have an easily accessible shopping quote cart. Clearly not optimized for the small fries shopping.

I was also going to pickup some DMM probes and they list the price with the Ask for Quote button, no buy button. They are probes..! I don't get it.

Anyways it's not letting me order, perhaps I need to wait to be approved.. I dunno. If you find a compatible plug let me know.

[GAD]

Offered $50 with the stipulation that it comes with all knobs and controls intact. He countered with $65, and I countered with $55, so yeah, it seems like $55 is the magic number. I've been curious about these for a while. Hell, more Agilent on the bench looks cool either way.

[Muxr]

Well they declined my account creation because I used my gmail address. I found one on Ebay that oughta work though since my money is not good for them.

http://www.ebay.com/itm/252223006400