Possible upgrade - Agilent 34410A to 34411A

[Zucca]

@dimmog we need the LED upgrade asap and the display Lens Acrylic Bezel with 34411a on it   

[TheSteve]

So nice this was finally solved.
Looks like the code only checks to see if it is a 34410 or not. The units I converted years ago were early proto units that likely had the 34411 byte set(or different bootloader code) and were then programmed as 34410. So it was easy to convert them to 34411 with no bootloader change.

[Cyclotron]

So nice this was finally solved.
Looks like the code only checks to see if it is a 34410 or not. The units I converted years ago were early proto units that likely had the 34411 byte set(or different bootloader code) and were then programmed as 34410. So it was easy to convert them to 34411 with no bootloader change.

I think you're one of the luckiest folks I know.

Yes, both models have the bootloader copy the model to memory, but only the app code for the 34411a actually checks it. I started exploring changes to the app code after reading bsw_m's great work. The bootloader modification is the right approach; you never have to worry about stepping on any copyright issues, and you can use the standard OEM firmware as delivered. 

bsm_m has gone to great lengths to make this safe and easy, since you don't even need to take the case off.  The code is very well done.
I beat it up and tested it a lot, and I only found minor issues, which have already been integrated into bsm_m's repo.

There is one caveat that I haven't really looked at. My 34411a shows as a converted unit, though it isn't.  The issue is that there simply isn't a lookup for the details matching my unit.  I really don't think anyone using the utility will be very interested in that path.

Note that all my tests were with app code ver 2.43, and I highly recommend that anyone using the utility go through the standard method to get their unit on that rev and validate it's healthy before pursuing the conversion.

[bsw_m]

@dimmog we need the LED upgrade asap and the display Lens Acrylic Bezel with 34411a on it   

I've already completely reverse-engineered the front-panel protocol and also partially reversed the front-panel MCU firmware. I'm now preparing everything for release on GitHub.

So this should make it possible not only to replace the custom COG VFD, which uses a serial data interface, but also to build an entirely new front panel with additional features — for example statistics, trends, and other useful functions.

[Zucca]

My 34411a shows as a converted unit, though it isn't.

I was blessed to get my hands on a 34411a in pristine condition cheaper than many 34410a.... so I will only do a backup.
That said I assume the 34410a will go up in $ soon, so do not hesitate to grab one if you need it.

[Cyclotron]

@dimmog we need the LED upgrade asap and the display Lens Acrylic Bezel with 34411a on it   

I've already completely reverse-engineered the front-panel protocol and also partially reversed the front-panel MCU firmware. I'm now preparing everything for release on GitHub.

So this should make it possible not only to replace the custom COG VFD, which uses a serial data interface, but also to build an entirely new front panel with additional features — for example statistics, trends, and other useful functions.

@bsw_m,  Thank you. That's super exciting.  I can imagine a front-panel rework with OLED and, heck, even touch controls, but that would mean a full front-panel swap.  Not out of the question with 3d printing and easy access to board manufacturing today.

[Zucca]

So this should make it possible not only to replace the custom COG VFD, which uses a serial data interface, but also to build an entirely new front panel with additional features — for example statistics, trends, and other useful functions.

Thanks I will not sleep for one week thinking about this. One thing to keep in mind is has to be EMI quiet, so no WIFI/Bluetooth. Obviously.
An IPS display could be a winner, OLED could burn in where the annunciators are.

Maybe annunciators in LED and OLED for the rest? 

The limit is the sky now. Amazing bsw!

[bsw_m]

I was thinking of using a display like this. Its dimensions fit the original front panel very well, so it should be possible to install it without modifying the instrument's front panel. I've attached the datasheet.

[bsw_m]

I've now published the complete results of the 34410A/34411A
front-panel reverse engineering.

It has grown quite a bit beyond just the VFD interface: the runtime
protocol, 8051 firmware behavior, keypad/SRQ handling and the original
firmware-update protocol are now documented, and I've also included
front-panel/PPC emulators.

GitHub:
https://github.com/AlexeyKozel/Agilent-3441x-DMM-front-panel

I've started a separate thread here for the technical details:
https://www.eevblog.com/forum/projects/agilent-34410a34411a-front-panel-reverse-engineering-protocol-8051-firmware

[TheSteve]

I think you're one of the luckiest folks I know.

Better to be lucky than good!

It's nice to know the countless hours spent trolling ebay does pay off at times

[HighVoltage]

I have two of the 34411A and several 34410A and therefore no need to "upgrade"!
But a big thank you for the amazing work!

[coromonadalix]

I have two of the 34411A and several 34410A and therefore no need to "upgrade"!
But a big thank you for the amazing work!

you will,   you will  loll

[Cyclotron]

I have two of the 34411A and several 34410A and therefore no need to "upgrade"!
But a big thank you for the amazing work!

you will,   you will  loll

I think I read that he has lots and lots of 34411a units.  At this point there's zero difference, right?

[coromonadalix]

we never talked about the keypad less L4411A     

[dimmog]

@dimmog we need the LED upgrade asap and the display Lens Acrylic Bezel with 34411a on it   

If you'd like, you can send me the display window and I can replace the original silkscreen with a laser-engraved "34411A" marking and Agilent logo.
See the attached picture for an example of how it looks on the 53132A.

[Hydron]

Go with one of the old HP logos just to mess with people.

Mine converted fine btw, thanks for the great work!

Out of interest, how should a fresh 34410A VFD compare in brightness to a fresh non-clone 34401A VFD? I though my 34410A was a little dim when received, but that was under bright lab lights and compared to an as-new (but 30 years old!) condition 34420A VFD; now that it's home it looks similar to my china clone 34401A VFD (which is perfectly acceptable). It's also nice and even so I'm wondering if they might have been a bit dimmer than the 34420A when new?

[hills]

OMG, I just found this today. I got a 34410A a few years back and I always loved it  - well, less the awful 747 take off noise the fan makes. it'll take some time to read and understand all the info, but it's incredibly exciting - and the prospect to indeed have a 34410-34411 conversione preserving the cal data is fantastic. Posting also to keep track of people experiences! And, Alexey, thank you.

我的天，历史十一年，刚好我今天正在想如何能升级，实在是帮大忙了

[dimmog]

Out of interest, how should a fresh 34410A VFD compare in brightness to a fresh non-clone 34401A VFD? I though my 34410A was a little dim when received, but that was under bright lab lights and compared to an as-new (but 30 years old!) condition 34420A VFD; now that it's home it looks similar to my china clone 34401A VFD (which is perfectly acceptable). It's also nice and even so I'm wondering if they might have been a bit dimmer than the 34420A when new?

A brand-new original VFD in the HP/Agilent 34401A had the same brightness as the 34420A VFD, and those are the brightest versions.

The VFD used in the 34410A is a little dimmer and is roughly comparable to the later-generation 34401A with the round buttons.
On the latest 34401A revision, they added two current-limiting resistors to the filament and made the display window more transparent.

The Chinese clone VFDs are dimmer than a new original VFD.

[Hydron]

Thanks @dimmog - that's very useful info.

Do you know whether the filament current limiting resistors extend display life? I'd assume so, but tubes are weird so I'm not making any assumptions. I may actually try and limit the current for my 34420A, both to increase the display life (this VFD is not readily available) and also make it a better match for the other two meters.

I had heard that the chinese 34401A VFD clones were dimmer, but didn't have a good reference until I got my 34420A - it's quite a big difference. Sadly your replacement display wasn't available at the time I replaced my 34401A display so I went down the clone route (it's much better than the original dim and variable display and totally usable, so not a big enough problem to do a second display swap though).

[coromonadalix]

i bought 34401a  cloned vfd's,   when the 1st generation of them came out at low price on Aliexpress,   they where bright like the originals, and still works ok ...  ?
only complaint was the bent was slightly more distant than the originals, they would touch the front panel plastic and could be damaged when sliding it ....


the newest   i dont know ...

[dimmog]

Thanks @dimmog - that's very useful info.

Do you know whether the filament current limiting resistors extend display life? I'd assume so, but tubes are weird so I'm not making any assumptions. I may actually try and limit the current for my 34420A, both to increase the display life (this VFD is not readily available) and also make it a better match for the other two meters.

I'm not sure unless you use it 24/7.

I think Agilent switched from Itron to Samsung mainly because Samsung was cheaper. From what I've seen, the Samsung displays don't last as long as the Itron ones.
My assumption is that Agilent was aware of this and added the current limiting to reduce filament stress and extend the VFD service life, at least to some extent.

The second-gen Chinese clone VFDs look very similar to the Samsung design. I also don't think the materials are any better, so I wouldn't expect these clones to have a very long life either.

[Zucca]

If you'd like, you can send me the display window and I can replace the original silkscreen with a laser-engraved "34411A" marking and Agilent logo.

I should send mine to Belarus to get Alexey's hand signature in a corner done with a Sharpie.

PS: I can imagine if you make the 34411a glass available, you will sell it.

[HighVoltage]

PS: I can imagine if you make the 34411a glass available, you will sell it.

Years ago, when I had a few of the 34411A and 34410A, I planned ahead and ordered all available replacement parts from Keysight. (Good old days) That is why I still have a few brand new 34411A Windows around and offer them for sale, if any of you are interested.

These are the 34411A windows, that I can offer:

1 x used Agilent branded Window Euro 15,-
3 x brand new Agilent branded Windows Euro 20,- each
4 x brand new Keysight branded Windows Euro 25,- each

Shipping cost depending on where you are, just ask.

I also have a brand new original 34410A Keysight VFD with complete PCB, if someone is interested.
That one was expensive but I just wanted top have.

Also a few new 34410A windows.

[Rubo]

I'll take one of the Keysight branded 34411A windows, please 

We can continue this over PM's

[Hydron]

I'll take a 34411A agilent window if shipping is reasonable to the UK. Will send a PM.