Agilent L4411A Multimeter teardown

[plesa]

Today I needs to clean Agilent L4411A Mutimeter so I take few photos.
This multimeter is almost identical to Agilent 34411A. It is based on LM399 voltage reference and TrueVolt technology.
I just thinking about disconnecting internal fan to make it silent, PSU seems not to be hot too much (57°C ).

It does not have internal transformer, but switching PSU (Phihong PSA25L https://phihong.com/html/psa25l_25w_compact_pcb.html ).

I found more teardown photos on internet fo someone who will needs more details.
http://letsdisassembleit.com/print.php?news.4
For comparison with 34410A
http://letsdisassembleit.com/news.php?extend.2

It is pretty small (1U instrument) only little bit longer than 34411A units (same lenght as 34401A).
Ideal for automation or someone using Agilent DMM Connection utility/BechVue only.
Combined with  40 channel multiplexer L4421A it offer decent datalogger unit.

[HighVoltage]

Thanks for showing us the insight of this instrument.
This L4411A cost Euro 2200 in Germany + VAT!
What makes this instrument so expensive, can not just be the 1U hight.
Somehow, I think I would prefer the 34401A or the 34411A for higher speed, but then, I never used the L4411A.

What are you planning to do with it?
 

[plesa]

Yes, this is identical to 34411A, so the price is about 250USD higher than 34411A.
What it makes so expensive ( compared to 34410A - 1050 USD difference) is speed 50k reading/s, 1M memory, Analog level trigering and pre+post triggering feature
Missing feature on 34410A/34411A is the ratio measurement capability available on 34401A. Which is again available on 34461A.
It cannot be used as bench meter which is obvious, reading is also available on front panel (16x2 LCD) including IP adress.
I'm using it mainly as 4W thermometer and logging purposes with LabView or with DMM connection utility.

[plesa]

Measured temperature on internal shield with disconnected fan 50°C, with fan connected 38°C and with open frame 40°C.
So keeping fan of on is must.
Today I also notices that banana sockets are nickel plated (difference to 34410A/34411A/34401A)
On internal photos is visible that they used tin coated faston for connecting input terminals, strange.
Eg. Keithley use gold plated banana sockets and pushon terminals not only on input terminal but also on voltage outputs and other banana terminals where emf is not so critical.
The amps wire is thinner than I will expect.

[Muxr]

Thanks for sharing. Pretty cool piece of gear.

[coromonadalix]

reviving it a little bit

Haven't found a schematic,  we do have some 34410a  schematics    but it differs on some sections,  use the same brain ic

They use some kind of an audio amp  ic  MSC  xxxxxx  to do the switching pulse transformer drive

It as an smps for the main 5 volt  and use this strange smps (huge transformer) to do the analog  +18 -18 and 5 vdc ...


The fan speed a lot  loll   kinda noisy too,   maybe use an resistor to drop the voltage 

[HighVoltage]

Pictures please

[coromonadalix]

loll    of ?     the main pcb ??

[HighVoltage]

loll    of ?     the main pcb ??

Yes, all the details of the main PCB.
I have repaired many 34401A and 34411A but never the L4411A
Would be nice to see the difference on the PCB.

Thanks

[coromonadalix]

here's some  high res

U1300  is a Xilinx ....   not sure i want to pry the sticker

And you thee the MSC  LX1722    audio amplifier  who act as an dc-dc converter driver / push pull   for the analog D/A  section  +18v -18v and +5v

U1000  the main ic under the ac lines,  is the same "Brain" controller for the 34410A,  Agilent 1822-0605   ??

U1104  is an ATMEL XXX   EEProm i think ??  i have a hard time to read it, ill use an web cam microscope  and do an update

[coromonadalix]

here's some  high res

you do see a familiar number there 

[coromonadalix]

here's some  high res

[coromonadalix]

here's some  high res

the fan is well hidden  ...  have cleaned it up,  but  it's kinda noisy to hear it   case opened

[coromonadalix]

here's some  high res


Yo do see some holes on the sub front panel frame   

The rears plugs and fuse socket could be moved to the front ??  maybe  design a new overlay for this ??


strange the photo show rotated

Some ghost photo  loll   
There are 3 layers of stuff,  the overlay,  you have the front panel plate, and the frame chassis,   for the down right hole, only the frame chassis hole is punched ??

[coromonadalix]

Shield plate removed

U302  Agilent  !ng4-0001   ASIC ?

A very high placed  crystal,  you sdont see it well  but it's lifted  5 mm  over the pcb  surface,  strain relief ??

A beautiful  LM399  reference

Some smt resistors, precision ??  R300 and R500

U700  an Xilinx Spartan  XC3S200

U505  AD9200A   10 bit 20mps AD converter 
https://www.analog.com/media/en/technical-documentation/data-sheets/AD9200.pdf

U506  AD9283   8-Bit, 50 MSPS/80 MSPS/100 MSPS
https://www.analog.com/media/en/technical-documentation/data-sheets/ad9283.pdf

U503  AD829   
https://www.analog.com/media/en/technical-documentation/data-sheets/ad829.pdf

[coromonadalix]

U1104  ATMLH220  16cm    who would be an 24c16  i think,     gonna try a dump,  but i dont know where to put the system in reset and hold it

https://ww1.microchip.com/downloads/en/DeviceDoc/doc0180.pdf

[coromonadalix]

that's all folks

[coromonadalix]

oh   just found this,  is it a debug port    a com port ??

I'm gonna try to find an ftdi  interface ...

[HighVoltage]

Thanks for all these nice pictures!

Yes, try to read the interface during bootup, nice find.

[coromonadalix]

9600 N 8 1   with an ftdi dongle at 3.3 volts
it does  show this :


Attaching interface lo0...done

Adding 26466 symbols for standalone.
AMDFLASH
-> rhapsodyInit: programInguard
0x13f87b8 (tOxf): FPGA ready
rhapsodyInit: initInstrumentEngine
KOM_gpib_config
KOM_int_cfgn
0x1206c68 (tUsb): Config EBIU USB Asynchronous Timings
0x1206c68 (tUsb): Previous USB EBIU_DCR_BR: 10188398
0x1206c68 (tUsb): NEW USB EBIU_DCR_BR: 10188368
0x1206c68 (tUsb): Config EBIU USB Synchronous Timings
0x1206c68 (tUsb): Previous USB EBIU_DCR_BR: 10188368
0x1206c68 (tUsb): NEW USB EBIU_DCR_BR: 10188162
0x11d4d70 (tPollVbus): USB connectPullUp = 1


But doesn't go as far as  the : https://www.eevblog.com/forum/testgear/possible-upgrade-agilent-34410a-to-34411a/     thread     loll    i need to read more   

BUT does respond to help

>help

help                           Print this list
ioHelp                         Print I/O utilities help info
dbgHelp                        Print debugger help info
nfsHelp                        Print nfs help info
netHelp                        Print network help info
spyHelp                        Print task histogrammer help info
timexHelp                      Print execution timer help info
h         [n]                  Print (or set) shell history
i         [task]               Summary of tasks' TCBs
ti        task                 Complete info on TCB for task
sp        adr,args...          Spawn a task, pri=100, opt=0x19, stk=20000
taskSpawn name,pri,opt,stk,adr,args... Spawn a task
td        task                 Delete a task
ts        task                 Suspend a task
tr        task                 Resume a task
d         [adr[,nunits[,width]]] Display memory
m         adr[,width]          Modify memory
mRegs     [reg[,task]]         Modify a task's registers interactively
pc        [task]               Return task's program counter


Type <CR> to continue, Q<CR> to stop:


iam       "user"[,"passwd"]     Set user name and passwd
whoami                         Print user name
devs                           List devices
ld        [syms[,noAbort][,"name"]] Load stdin, or file, into memory
                               (syms = add symbols to table:
                               -1 = none, 0 = globals, 1 = all)
lkup      ["substr"]         List symbols in system symbol table
lkAddr    address              List symbol table entries near address
checkStack  [task]             List task stack sizes and usage
printErrno  value              Print the name of a status value
period    secs,adr,args... Spawn task to call function periodically
repeat    n,adr,args...    Spawn task to call function n times (0=forever)
version                        Print VxWorks version info, and boot line

NOTE:  Arguments specifying 'task' can be either task ID or name.

value = 1 = 0x1


> version
version
VxWorks (for Agilent KOM PPC405, SA27E rev1) version 5.5.1.
Kernel: WIND version 2.6.
Made on Oct 19 2010, 19:20:14.
Boot line:
emac(0,0)host:vxWorks h=10.1.1.2 e=169.254.9.80 u=demo pw=demo tn=
value = 78 = 0x4e = 'N'
->

[coromonadalix]

If i search for   Agilent KOM PPC405

it show  a few threads here



The sad thing about the meter is the java version needed for the web page interface, mostly the instrument  "web control section" says  no java found   but i'm at the latest v8 xxx version

 

[HighVoltage]

If your Java version is too new it will not work. I had this problem on a different Agilent instrument and had to downgrade Java for it to work. I do not remember the details but it was totally stupid.

[coromonadalix]

yeah  thks 

That's what i think ....

[NNNI]

Shield plate removed

U302  Agilent  !ng4-0001   ASIC ?

A very high placed  crystal,  you sdont see it well  but it's lifted  5 mm  over the pcb  surface,  strain relief ??

A beautiful  LM399  reference

Some smt resistors, precision ??  R300 and R500

U700  an Xilinx Spartan  XC3S200

U505  AD9200A   10 bit 20mps AD converter 
https://www.analog.com/media/en/technical-documentation/data-sheets/AD9200.pdf

U506  AD9283   8-Bit, 50 MSPS/80 MSPS/100 MSPS
https://www.analog.com/media/en/technical-documentation/data-sheets/ad9283.pdf

U503  AD829   
https://www.analog.com/media/en/technical-documentation/data-sheets/ad829.pdf

I recently got one of these and would like to take a peek under the hood. I removed the one screw visible that was holding the shield in place, but looks like there are some hooks that go under the PCB. How did you manage to remove it?

[coromonadalix]

the shield plate if i remember slide the opposite way of the screw

when it stop,  carefully lift the plate