Agilent 34410A, Repair of 2 dead meters [success]

[chihaxinh]

HI High Voltage

What cause can kill relay ? Overvoltage or short to burn coil ? So many 34401A using and hard to finding relay to replace 

[HighVoltage]

HI High Voltage

What cause can kill relay ? Overvoltage or short to burn coil ? So many 34401A using and hard to finding relay to replace 

I think this one was killed by over voltage, probably far exceeding the 1000V DC limit of the meter, because of the damaged components in the input signal path.
Yes, I was also very much surprised that such a relay could not be obtained from "normal" vendors and that I had to buy it from Keysight. No other option. May be one day someone will find a better sourse.

Looks great - just how many bench DMM's do you have in the lab now?

Well, we had this thread here called "Why does everyone have 20 Oscilloscopes" or so
I probably have 20 Bench DDM's, if I add all my lab benches together.
Most of them Agilent / Keysight but also a few old BBC Metrawatt meters.
May be I should make a picture with all of them?
 

[TheSteve]

A picture would be great. I'd need more bench to have that many meters, it does sound fun though. Twenty DMM's is better then twenty scopes...

[HighVoltage]

OK, here we go,
I just gave two HP branded 34401A meters away to a friend after repair otherwise they would have been in the picture as well.
These are all my bench top meters from different benches. First time they are lined up like this on the same table.

[Nuno_pt]

HighVoltage, if you ever feel again in a give away mod on another 34410A, and want to send it my away I don't mind give him a new home. 

[TiN]

No 3458? Booo 

Nice stash. Now hook them all to stable 10V and make some neat charts...

[TheSteve]

OK, here we go,
I just gave two HP branded 34401A meters away to a friend after repair otherwise they would have been in the picture as well.
These are all my bench top meters from different benches. First time they are lined up like this on the same table.

Now everyone will want to be your friend!

Great shots, so much great HP/A/K gear with just a few Keithley goodies tucked in.

[HighVoltage]

No 3458? Booo 

Nice stash. Now hook them all to stable 10V and make some neat charts...

The 3458A is still on my wishlist. It is not easy to find a good one that is also right in the price range.
May be one day I will have one.

Good idea to hook them all up and make a comparison chart.
Indeed, that will be interesting, let me see if I get to that.
I need to build a few cables first to hook them all up at the same time to my 10V SVRT.

 

[HighVoltage]

Now everyone will want to be your friend!
Great shots, so much great HP/A/K gear with just a few Keithley goodies tucked in.

The Keithley Source meters are just amazing, especially the 2450 with the high precision in the lower values.
This 1 nA DC current measurement with the 34470A had the 2450 as a 1nA source. (See pictures)

But somehow I find the 34401A and the 34410A easier to repair than the Keithley meters.
But then .... may be I am just addicted to Agilent gear and not so much to Keithley instruments.

[Helix70]

When did the Agilent 34401A front panel change from rectangular buttons to rounded ones? Mine are rectangular..

[Macbeth]

When did the Agilent 34401A front panel change from rectangular buttons to rounded ones? Mine are rectangular..

It's a 34410A not a 34401A.

Yeah, I didn't know about them before this thread either. On my radar now 

ETA: Oh, it looks like the '01s with the rounded buttons are a thing. The Keysight version?

[HighVoltage]

When did the Agilent 34401A front panel change from rectangular buttons to rounded ones? Mine are rectangular..

I think the round button on the 34401A was introduced around 2009 or 2010, by Agilent, long before it became Keysight
It was kind of a facelift with no other technical changes.
The Keysight branded 34401A kept everything the same besides the logo.

The 34410A always had round buttons as far as I know.


 

[Helix70]

I have a 34401a that is missing a serial number sticker. The calibration message says 2006-06 with 35 calibration counts. The anti tamper stickers are in tact on the rear screws. Any way to date the meter and is there another way to get the serial? *idn? Says 0.

Was the original cal 2 years after manufacture?

[HighVoltage]

I have a 34401a that is missing a serial number sticker. The calibration message says 2006-06 with 35 calibration counts. The anti tamper stickers are in tact on the rear screws. Any way to date the meter and is there another way to get the serial? *idn? Says 0.

Was the original cal 2 years after manufacture?

You can find out the serial number by requesting it through GPIB or Serial interface on the 34401A.
The serial number is part of the returned IDN string for the instrument.
The IDN string is usually returning the following string:
<Manufacturer>,<Model Number>,<Serial Number>,<Firmware Revision>
When sending "*IDN?" to the Agilent 34401A, you should see something like:
"AGILENT,34401A,0,11-5-2"

The calibration cycle depends on the user and it can be 1 year or two years.

[plesa]

I have a 34401a that is missing a serial number sticker. The calibration message says 2006-06 with 35 calibration counts. The anti tamper stickers are in tact on the rear screws. Any way to date the meter and is there another way to get the serial? *idn? Says 0.

Was the original cal 2 years after manufacture?

You can find out the serial number by requesting it through GPIB or Serial interface on the 34401A.
The serial number is part of the returned IDN string for the instrument.
The IDN string is usually returning the following string:
<Manufacturer>,<Model Number>,<Serial Number>,<Firmware Revision>
When sending "*IDN?" to the Agilent 34401A, you should see something like:
"AGILENT,34401A,0,11-5-2"

The calibration cycle depends on the user and it can be 1 year or two years.

With this example the meter does not contain serial number, there are lot of instruments made by HP and Agilent which will respond to *IDN? query like HighVoltage mentioned (HEWLETT-PACKARD,34401A,0,10-5-2 in my case).
These meter does not contain SN.
Also calibration count does not count the number of calibrations but more it is counter of value changes, so during one calibration you can change cal count more than +1 only.

[Helix70]

Sorry, i wasn't clear.. The field for serial number on mine returns a 0. I get the full message for *IDN?

[HighVoltage]

I bought another one of these meters, well, this one is the 34411A, the big brother to the 34410A with higher speed and a much higher price sticker. My price was Euro 100. The official price in Germany is right now crazy Euro 2600 incl. VAT.

This one was offered to me broken - "Not turning ON" and I expected another nice repair job for a Sunday.
But I opened it up and found the power cable from the transformer unplugged from the PCB ... hmmm what an odd thing to discover.
Interestingly the fuse was also blown.

Solution:
Plug in the cable, replace the fuse and turn on.
It seems to work well.

This unit was sold by Agilent in 10/2012
Date-codes on the chips are 2212

This instrument has the yellow Kapton tape on top of the electrolytic capacitors, same as some of the last 34401A instruments I got.
But the previous 34410A that I repaired did not have the tape.
May be the changed production procedures to protect the capacitors from heat?

OK, I will start some sampling from my Geller SVRT to see if the unit has a drift.

May be I should get it fully calibrated.

[HighVoltage]

two more pictures

[lowimpedance]

I bought another one of these meters, well, this one is the 34411A, the big brother to the 34410A with higher speed and a much higher price sticker. My price was Euro 100. The official price in Germany is right now crazy Euro 2600 incl. VAT.

This one was offered to me broken - "Not turning ON" and I expected another nice repair job for a Sunday.
But I opened it up and found the power cable from the transformer unplugged from the PCB ... hmmm what an odd thing to discover.
Interestingly the fuse was also blown.

Solution:
Plug in the cable, replace the fuse and turn on.
It seems to work well.

......... geez some guys have all the luck!.
Nice meter btw.

[Nuno_pt]

HighVoltage, you've to tell me how you find this things, I'm still looking for a 34401 to fix, or one of that for a decent price, but seems I can't find any at that price range.

Nice score. :-)

[HighVoltage]

HighVoltage, you've to tell me how you find this things, I'm still looking for a 34401 to fix, or one of that for a decent price, but seems I can't find any at that price range.

Nice score. :-)

Thanks...
It works best when the seller:
1. Puts the instrument it in a wrong category
2. Does not know how to spell "Aiglent"
3. Does not turn the unit on to proof its working
4. Mixes up the model number eg 3401 instead of 34401A

But you have to take a risk as well.
Sometimes I buy "the cat in the sack" when there is only a stock picture shown.
Many times I get lucky but sometimes I also lost in the past.
Most of those time Paypal Protection helps

If you keep looking, you will finally get one.
Look on ebay France, they really don't know how to spell English words correctly - many times.
And usually I find interesting instruments there.

But I better stop talking, otherwise I will no longer find these scores.

[HighVoltage]

1 hour later

Interestingly, the 34411A shows the lowest standard deviation of 1.5 uV

[plesa]

Congratulation to additional 3441xA meter You are like TiN with Keithley DMM

[Dr. Frank]

Hello HighVoltage,
and congrats to your crisp 34411A.
As the 465A/470A with Digitizing option are promoted to be successors to the 34411A,but do not perform well regarding data transfer in BenchView, would you mind checking, if the 34411A operates better?
That means, is it possible to transfer data in real time to benchview, with highest sampling rate 50kSa/s, w/o delay due to buffering?

THX

Frank

[bitseeker]

I bought another one of these meters, well, this one is the 34411A, the big brother to the 34410A with higher speed and a much higher price sticker. My price was Euro 100. The official price in Germany is right now crazy Euro 2600 incl. VAT.

This one was offered to me broken - "Not turning ON" and I expected another nice repair job for a Sunday.
But I opened it up and found the power cable from the transformer unplugged from the PCB ... hmmm what an odd thing to discover.
Interestingly the fuse was also blown.

Solution:
Plug in the cable, replace the fuse and turn on.
It seems to work well.

......... geez some guys have all the luck!.
Nice meter btw.

You can say that again. Nice score, HV! Amazing.