Agilent 34461A display failure......suggestions please!

[300DT]

Hello!

My 34461A meter screen is working, but freezing when it initiates.

It comes up with the Agilent Technologies screen and a black scroll bar (all in black and white, not colour). Then the screen info disappears and  goes dark.

No amount of button pushing will get it going unless you cycle the power switch and the same thing happens over and over on each recycle-button-push.

All voltages check out OK as per the "trouble shooting" section of the manual.

I have checked all the frequency generating sources and they are all ok except for one 25MHz crystal that is 2K low in frequency.(not probably a problem)

This has me baffled and I am considering a "reball" of the bga chips, but am looking for any suggestions first. I'd be happy with just a schematic to get things going!!!!

Thank You!

Mike

[LA7SJA]

If it's out of warranty then try;

1.) Is it on a network?
2.) If so, can you ping it?
3.) If you can ping it, you could try a "remote" firmware upgrade with the "Keysight Firmware Update Utility" select LAN(Socket) IP address.

Johan-Fredrik

[300DT]

Hello Johan-Fredrik!

Thank you for the suggestion. My meter however is freestanding and is not on a network and has never been hooked up to one.

I suspect that it does not even initiate itself.

The display board has 3 BGA chips and one small CPU on it that may have failed and are suspect.

Without a schematic I can just generalize and look at the function of most of the chips.

Dave's 34461A disassembly video is very helpful in this regard.

Thank You!

mb 

[HighVoltage]

If it is only the display that is not working, you should be able to connect with the Keysight I/O Library through the network adapter, as long as it is set to obtain an IP address automatically.
Also, it is might be helpful to get a GPIB adapter and connect that way.

How old is the DMM?
Did something happen, that caused this problem, as far as you know?

[wraper]

First of all this is not "display failure" but failure to boot.

This has me baffled and I am considering a "reball" of the bga chips

More and more I tend to think that people should be publicly prosecuted for such suggestions.
Return it under warranty, it has 3 years. Your chancet to repair it by soldering, replacing some part, are rather slim IMO. Very likely this is NAND corrupted.

[LA7SJA]

First of all this is not "display failure" but failure to boot.

This has me baffled and I am considering a "reball" of the bga chips

More and more I tend to think that people should be publicly prosecuted for such suggestions.
Return it under warranty, it has 3 years. Your chancet to repair it by soldering, replacing some part, are rather slim IMO. Very likely this is NAND corrupted.

I'm guessing it's the same NAND corruption that happened on the DSO X2xxx and DS3xxx osciloscope (perhaps the same routine in the program that is reused either way). If it was my instrument as I would have borrowed, bought or stolen a router or a hub and tried to hook me up against the instrument and attempt to reinstall the firmware (34460A/34461A Revision 2.08 Enhancements and Fixes has this cryptic line: 8. Removed internal errors caused by a fast power cycle using the front panel button.) It is my opinion that the only thing you will achieve with the soldering iron is ruining the meter further.

Johan-Fredrik

[300DT]

Hello Johan-Fredrik, Wraper and HighVoltage,

Thank you for your suggestions.

The last thing I want to do is to have to replace parts on such a lovely instrument.

It was given to me to be dismantled for parts, but I couldn't bring myself to do so, seeing that it is "ALMOST" functioning.............like a chain with a rusted-through link!!!!!!

I could never afford to buy such a meter, and carry out most of my amateur radio-hobby activities with secondhand, surplus HP,TEK, and other test equipment.

Johan-Fredrik, I will follow your suggestion and download the firmware upgrade. The newest one on the manufacturer's site is version 2.14. It looks to me that the most direct way of accessing the unit is via the front USB port and and an updated/programmed USB drive. I just hope that that the firmware can be updated without having the meter "boot-up", as I think that Wraper is right in stating that the meter's main problem is that it is not able to boot up.

Thank you all. I'll report back when I have tried the remedies.

Mike, VE3BNB

 

[TheSteve]

I would say flash corruption or failed ram myself.
If you're interested in selling it I am sure there would be multiple people interested, including myself

[wraper]

Have you verified warranty status? https://service.keysight.com/infoline/public/details.aspx?i=COV&pn=&sn=&lc=&cc=. Or has it been compromised while poking around so it won't pass for warranty?

[6thimage]

The nand contains two firmware images, one is the normal firmware and one is a backup. The backup is a very basic firmware which only allows the flashing of a new firmware image - when you boot from it you get a black screen for quite a while (but less than a couple of minutes if I remember) then a white screen with the instrument model number, serial, IP address and the message 'Follow support instructions to restore the firmware'.

You can force the booting of this second image by connecting a serial interface to the back of the front panel. During boot hold down space (I think) and it will stop at a uboot prompt. Then type in 'run bootcmd' hit enter then immediately hold down space. This should drop you into a windows CE bootloader and should say something like

Microsoft Windows CE Bootloader Common Library Version 1.4 Built May 22 2012 09:09:57
Microsoft Windows CE 6.0 Ethernet Bootloader for the Agilent P500 board
Adaptation performed by Agilent Technologies (c) 2008

Reading NAND configuration

P500 Boot Loader Configuration :

Mac address .......... ()
Ip address ........... ()
Subnet Mask address .. (255.255.255.0)
DHCP ................. (Enabled)
Boot delay (seconds).. (0)
Load image 1 at startup

Image addresses. (0xdxxxxxxx for NAND, 0x8xxxxxxx for RAM)
1 (0xd0620000)
2 (0xd2120000)

l) Load memory resident image Load image 1 now
1) Load memory resident image 1 now
2) Load memory resident image 2 now
3) Load memory resident image 3 now
d) Download from platform builder now
u) Start u-boot by resetting
v) Verify Images

If you enter 2 and hit enter it should load the backup. If anything goes wrong, the serial console is the best place to look.

And please don't try and reball or resolder any of the boards, the chances of a bad solder joint being the fault are incredibly small especially considering the temperature these chips run at.

[edit]
If you don't get to the coloured boot screen, then windows CE hasn't finished booting. If it hasn't finished booting, then you won't be able to update the firmware via USB (as it is part of the application) or Ethernet (as the tftp server is enabled via a SCPI command).

There are two main processors on the front panel board - the spear ARM processor and an NXP microcontroller. The spear runs everything, the NXP is used for the soft power button.

If you are seeing an agilent boot screen, when you update to the keysight firmware it will take a while at boot and it does look like it has frozen (for a couple of minutes), just leave it, it will get there eventually.
[/edit]

[lowimpedance]

@ 6thimage,  A most useful post for others who might also come across this issue with one of these meters at some stage, (out of warranty at least and wish to tackle it themselves).
 

Will be interesting to hear the results from 300DT.

[300DT]

Thank you 6thimage!!!!!

What a lot of information to digest.......

As you stated,  "If it hasn't finished booting, then you won't be able to update the firmware via USB". I tried updating the meter using the Firmware Update Utility and did not get anywhere. No boot no pleasure!

Then I went for supper leaving the unit on. On my return an hour later,  I found, to my surprise, that the screen turned bright white in colour, and when I picked up the unit I burned my thumb on the "Spear" processor. This processor was hot to the point of burning my skin. It was NOT this hot before. Obviously it failed, by itself, just by being left running.

Consequently the screen now does not come up with the black and white "Agilent" notice and freeze, as it did before. Now, after cool-down, I get a bright white screen with no image displayed. I fear I need a new "Spear320-s".

This is my report for today. Thank you All for your help so far!

Mike VE3BNB

 

[max_torque]

Hey, what was the outcome of this failure?

My 34461A has just failed with what looks to be the same failure, just a white (blank) screen after power on, nothing else 

 

[wraper]

Hey, what was the outcome of this failure?

My 34461A has just failed with what looks to be the same failure, just a white (blank) screen after power on, nothing else 

 

If it is not one of the early units, it still should be under 3 year warranty. I would not suggest trying to fix this if you still have warranty.

[HighVoltage]

Even the early instruments should still be covered by full warranty since the factory warranty was extend by one year on all 3446xA and 34470A models because of the voltage reduction debacle.

[wraper]

Even the early instruments should still be covered by full warranty since the factory warranty was extend by one year on all 3446xA and 34470A models because of the voltage reduction debacle.

AFAIK it's not certain if warranty extension was ever implemented. And in the end spec derating was cancelled as this was a false alarm.
EDIT, actually extension is valid:

we are providing an additional 1-year
warranty extension for all the units with SN listed in this service note.
Remark: Product that is currently out of warranty will have its warranty extended to 31st March 2018

[max_torque]

i think the unit is around 16 months or so old, but i had assumed it had a 12month warranty!   So, back to meet it's makers it goes!   

[elcal]

Sorry for revieving a old post, but i've struggled with this exact case as described here.

I've manged to get to the Menu «Follow Support Instructions to Restore Firmware» thanks to the help of all of you!

Can someone provide these instructions? How can you upload the firmware to the instrument once you have booted into the backup Firmware?

Thanks

Chris

[mr.fabe]

Here are the instructions to update via Front Panel USB port...

[elcal]

The backup is a very basic firmware which only allows the flashing of a new firmware image - when you boot from it you get a black screen for quite a while (but less than a couple of minutes if I remember) then a white screen with the instrument model number, serial, IP address and the message 'Follow support instructions to restore the firmware'.

In this backup FW Mode, you cannot use the Front panel keys unfortunatley. I would need the "support instructions to restore the firmware".

[pasta2018]

check tps2051B pin 5,this is a over current protect, if there is an over current, pin 5 will be pulled to low logic.

[autorepair78]

Thank you 6thimage!!!!!

What a lot of information to digest.......

As you stated,  "If it hasn't finished booting, then you won't be able to update the firmware via USB". I tried updating the meter using the Firmware Update Utility and did not get anywhere. No boot no pleasure!

Then I went for supper leaving the unit on. On my return an hour later,  I found, to my surprise, that the screen turned bright white in colour, and when I picked up the unit I burned my thumb on the "Spear" processor. This processor was hot to the point of burning my skin. It was NOT this hot before. Obviously it failed, by itself, just by being left running.

Consequently the screen now does not come up with the black and white "Agilent" notice and freeze, as it did before. Now, after cool-down, I get a bright white screen with no image displayed. I fear I need a new "Spear320-s".

This is my report for today. Thank you All for your help so far!

Mike VE3BNB

Hi
Did you change SPEAR320 and was ok? I'm asking because I have similar problem. My 34461A has only withe screen and very hot spears320

[yuhar]

I just want to replace it, but the part has not yet arrived...

Same situation hot Spear320, white display.

[autorepair78]

Where did you buy this procesor?

[coromonadalix]

Some of them are still sold .... around 10-12 $ usd      But many are saying   end of life