LeCroy 9310C DSO--Free from dumpster. Has an issue with Ch1 input attenuator, but doesn't appear too serious.
Wow! Was there an electronics shop that used the dumpster?
Not sure how much of a score yet, but I got an HP E3615A DC 0-20 V, 0-3 A, 60 W Power Supply for $75 including shipping.
Negative binding post is red??? and ground binding post is black???
At least the positive one is red
I'll swap the negative and ground and search for a green binding post to replace the red one or just paint it or something.
Look in pretty good condition (other than the binding posts with the wrong colors)
Not sure how much of a score yet, but I got an HP E3615A DC 0-20 V, 0-3 A, 60 W Power Supply for $75 including shipping.
QuoteNot sure how much of a score yet, but I got an HP E3615A DC 0-20 V, 0-3 A, 60 W Power Supply for $75 including shipping.
Classic, I bought one of the others (there were three for sale). I'll be interested to see if it works, but I'm not really worried, looking at the description they should be at least an easy repair.
I've got a couple of other HP supplies (6205C, 6237A), and they've got the same scheme, all red except for earth. They seem to have changed to red / green / black only a little before becoming Agilent.
Snapped up an Advantest R6581 for $500 a while back, it's an 8.5digit multimeter. Think of it like a baby 3458A, 2-3 times worse on linearity (0.1ppm) and noise(0.025ppm RMS), but it does have artefact calibration and hey, I can't really complain because of the price. I dig the dual line display, it's very easy to use. 5ppm per year accuracy on DC volts, and a tempco of 0.15ppm with autocal.
The seller described it as broken, because on power-up there was no reading shown, and the relays were clicking non-stop rapidly, hence listing it for so cheap. This meter always self tests on power on, and the seller's photo did not show any error annunciators.
Upon arrival, yep, it's as the seller described. I ran the internal calibration (which is like the AutoCal on HP), and hey, it all seems to work just fine until I power cycled the meter. It then showed error -315 "configuration memory lost".
10 bucks and 2 solder joints later, she works a treat. It's a standard 1/2AA 3.6V battery, axial lead with 1.25inch spacing. Access to the battery is easy, just remove a couple of cables in the way, there's no need to take off any shielding.
The local cal lab said it was 9ppm off on 10V DC, and was adjusted to be 0.3ppm off. There weren't any stickers on the unit I have so who knows when it was last calibrated. I don't have the cash for a proper calibration with a Josephson-Junction ($1.8k+), so I'll have to live with their stated 2.4ppm uncertainty. They did have their 10V reference freshly calibrated, hopefully it's a bit better than that in practice.
My unit was made in Feb 1998 according to the battery, and there must be other units running out of batteries, so I hope by posting this you guys can snag a good deal too!
Hi Deadly Lover,
as a 3458A / AUTOCAL owner, I'm greatly interested in a teardown of the mysterious R6581, and maybe you have any manuals to share. (these are not available on the net)
Especially I'm interested, how the autocal and in conjunction the basic calibration of the R6581 works, i.e. if also 2 artefacts (10V, 10kOhm) are necessary only.
Frank
Yup, it is also 2 source 10V and 10kOhm artefact calibration, same as 3458A.
It has something called "Internal Calibration", I suspect that it is just their version of AutoCal as the spec sheets indicate that it's for the tempco compensation. You can perform the INT CAL separately for DCV, Ohms and AC, just like AutoCal.
I'm also curious how it can calibrate ACV, ACI and frequency ranges, maybe you simply cannot? I couldn't find anything about it in the manual. I guess because it doesn't have the fancy synchronous AC mode like the 3458A, there is no need for adjustment for the R6581 AC ranges. It's ACV specs are nothing to write home about, pretty similar to the 3458A in analog AC mode. It is quite a mystery...it lacks an equivalent of SCAL on the 3458A...
There are no English manuals unfortunately, the only one I can find is in Japanese on the ADCMT site and is a pain to translate because Adobe Reader has a hard time recognising the Japanese characters. The pages were scanned as images. I uploaded it here, it's a biggie at 35MB. https://www.dropbox.com/s/67vd6qj0ob7mh5h/R6581%20manual.pdf?dl=0
You can find some good teardown photos of the R6581T here at 38hot, it may be slow to load because it only loads pictures as you scroll down. http://bbs.38hot.net/thread-212-1-1.html
The difference between the R6581 and the R6581T/D is that the latter only has DC and Ohms functionality, and with limited range on DC, like 100V DC range maximum.
I really don't want risk messing with the R6581 calibration until I acquire a stable voltage and resistance reference, so I don't think I can teardown the unit just yet, sorry! It will happen eventually though, I'm sure!
The mains turn on spike can also be caused by the in-rush current of the supply if your measurement method is inappropriate (where did you "ground" the negative post?)
A bit hard to judge at 10 ms/div...
The mains turn on spike can also be caused by the in-rush current of the supply if your measurement method is inappropriate (where did you "ground" the negative post?)
A bit hard to judge at 10 ms/div...I tend to agree. Leave the output completely floating, and use coax directly to the scope. Don't create that ground loop by grounding the supply output.
Also to the OP, the meters are easy to adjust with multi turn pots on the display board. Yours seem pretty consistently 1% or so high.