Products > Test Equipment
My poor mans SMU - The Agilent 66311B
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FrankE:
It's back in the game again (well, at least to diagnose).  I replaced the 5A PCB fuses I blew late last night.  I replaced the Papst 12V fan which itself looks like a retrofit with a  San Ace 60 S Series 12V fan (from Farnell). Rated 0.4m³/min (14.1cu.ft/min) 16dBA. It is much quieter and I haven't yet fitted an isolation gasket.
It didn't come with a molex connector attached, (it's a 3 wire BTW) so I had to bodge it on with a connector block as I don't have a Molex crimper yet.
It soon ramps up full tilt despite no/low load i.e having 13.9V across it. Seriously, HP/Agilent is that fan speed really necessary
Input rails are fine.
No idea where to use as the common for the crowbar and reverse. My scope is broke so I can't see the gating. My 289 is away to Fluke, so it's getting a bit of a nuisanse swapping leads.

Now I can't get the output to shift from 8.000V.
I set it there after not previously being able to shift it from some other nominal voltage.
Perhaps it's on remote. "Address 0" is displayed in the boot sequence and I was fiddling in that menu.
I can't see the firmware option
Hmm, RTFM etc.

edit: oops, I forgot one of the 125mA  fuses had popped

I can't see any full schematics anywhere so there's a lot of guesswork
Once I get it fully working, would I get any better precision/ performance if I replaced the LM 78xx CGT and LM 79xxCGT the +/- 4% with LM 78xxACTG and LM79xxACTG the +/- 2% versions or are the subsequent stages taking care of the precision?

FrankE:
Yay, repaired it. The crowbar circuit was gone (broken trace). Oh well, didn;t need those 2% LM 78xx LM79xx ACTG regulators. Might use them to build a 5680 10MHz Rb frequency standard.
It's running nice and quietly with a new fan
It has firmware A01.08.
What's to be gained from changing to a later ROM revision e.g. A 02.04 Any additional functionality?
I don't have a GPIB converter and they are horrendously expensive second-hand, so I'd need to buy an Atmel AT27C2048 and see if the local hackspace has an EEPROM programmer.
What can I do with the serial port? Is there any freeware one can use to control the 63311B or log?
I'm not sure how the calibration is but I get my 289 back from Fluke within a couple of days, which I assume will come with some sort of post repair/board change factory cal.
TheSteve:
Nice to hear you've brought it back to life!
FrankE:

--- Quote from: TheSteve on April 24, 2016, 04:12:15 pm ---Nice to hear you've brought it back to life!

--- End quote ---

Many thanks for the heads up on the deal.
It was my own fault, I might have broken it by allowing a scalpel to drop in it.
It's running really quietly 15.386V 2.6A powering a screenless laptop I found, so worth changing the fan.

This firmware upgrade. Is it worth it? I have the through hole version A01.08. I read SMT was introduced in 1999. Is 02.04 even compatible?
I got an Atmel IC today from RS, I don't have an EEPROM programmer and I couldn't justify buying even a TL866 this month but someone said they could do it with an Arduino. Whether 'could' is 'will' is yet to be seen.
TheSteve:
No idea on the firmware update - I'd be tempted to leave it though, especially if you don't have a programmer handy. I love updating firmware on stuff but there is always the risk/reward factor. I'd also backup the calibration data before messing with it if you do attempt it.
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