Agilent L4411A Multimeter teardown - Page 1
Forum section: electronics / testgear

author: plesa
author_rank: Frequent Contributor
timestamp: August 19, 2015, 05:00:03 pm
content: 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 PSA25Lhttps://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.4For comparison with 34410Ahttp://letsdisassembleit.com/news.php?extend.2It 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.

author: HighVoltage
author_rank: Super Contributor
timestamp: August 20, 2015, 10:04:52 am
content: 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?

author: plesa
author_rank: Frequent Contributor
timestamp: August 20, 2015, 10:45:57 am
content: 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 featureMissing 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.

author: plesa
author_rank: Frequent Contributor
timestamp: August 20, 2015, 03:46:38 pm
content: 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.

author: Muxr
author_rank: Super Contributor
timestamp: August 20, 2015, 03:51:03 pm
content: Thanks for sharing. Pretty cool piece of gear.

author: coromonadalix
author_rank: Super Contributor
timestamp: October 25, 2022, 04:22:37 pm
content: reviving it a little bitHaven't found a schematic, we do have some 34410a schematics but it differs on some sections, use the same brain icThey use some kind of an audio amp ic MSC xxxxxx to do the switching pulse transformer driveIt 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

author: HighVoltage
author_rank: Super Contributor
timestamp: October 25, 2022, 06:27:08 pm
content: Pictures please

author: coromonadalix
author_rank: Super Contributor
timestamp: October 27, 2022, 11:51:04 am
content: loll of ? the main pcb ??

author: HighVoltage
author_rank: Super Contributor
timestamp: October 27, 2022, 01:35:51 pm
content: Quote from: coromonadalix on October 27, 2022, 11:51:04 amYes, all the details of the main PCB.I have repaired many 34401A and 34411A but never the L4411AWould be nice to see the difference on the PCB.Thanks

author: coromonadalix
author_rank: Super Contributor
timestamp: October 31, 2022, 03:31:05 pm
content: here's some high resU1300 is a Xilinx .... not sure i want to pry the stickerAnd 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 +5vU1000 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

author: coromonadalix
author_rank: Super Contributor
timestamp: November 02, 2022, 10:38:11 am
content: here's some high resyou do see a familiar number there

author: coromonadalix
author_rank: Super Contributor
timestamp: November 02, 2022, 10:38:59 am
content: here's some high res

author: coromonadalix
author_rank: Super Contributor
timestamp: November 02, 2022, 10:41:45 am
content: here's some high resthe fan is well hidden ... have cleaned it up, but it's kinda noisy to hear it case opened

author: coromonadalix
author_rank: Super Contributor
timestamp: November 02, 2022, 10:43:28 am
content: here's some high resYo do see some holes on the sub front panel frameThe rears plugs and fuse socket could be moved to the front ?? maybe design a new overlay for this ??strange the photo show rotatedSome ghost photo lollThere 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 ??

author: coromonadalix
author_rank: Super Contributor
timestamp: November 02, 2022, 10:45:12 am
content: Shield plate removedU302 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 referenceSome smt resistors, precision ?? R300 and R500U700 an Xilinx Spartan XC3S200U505 AD9200A 10 bit 20mps AD converterhttps://www.analog.com/media/en/technical-documentation/data-sheets/AD9200.pdfU506 AD9283 8-Bit, 50 MSPS/80 MSPS/100 MSPShttps://www.analog.com/media/en/technical-documentation/data-sheets/ad9283.pdfU503 AD829https://www.analog.com/media/en/technical-documentation/data-sheets/ad829.pdf

author: coromonadalix
author_rank: Super Contributor
timestamp: November 02, 2022, 10:45:59 am
content: 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 ithttps://ww1.microchip.com/downloads/en/DeviceDoc/doc0180.pdf

author: coromonadalix
author_rank: Super Contributor
timestamp: November 03, 2022, 11:06:16 am
content: that's all folks

author: coromonadalix
author_rank: Super Contributor
timestamp: November 04, 2022, 01:14:30 am
content: oh just found this, is it a debug port a com port ??I'm gonna try to find an ftdi interface ...

author: HighVoltage
author_rank: Super Contributor
timestamp: November 04, 2022, 09:43:12 am
content: Thanks for all these nice pictures!Yes, try to read the interface during bootup, nice find.

author: coromonadalix
author_rank: Super Contributor
timestamp: November 04, 2022, 10:23:49 am
content: 9600 N 8 1 with an ftdi dongle at 3.3 voltsit does show this :Attaching interface lo0...doneAdding 26466 symbols for standalone.AMDFLASH-> rhapsodyInit: programInguard0x13f87b8 (tOxf): FPGA readyrhapsodyInit: initInstrumentEngineKOM_gpib_configKOM_int_cfgn0x1206c68 (tUsb): Config EBIU USB Asynchronous Timings0x1206c68 (tUsb): Previous USB EBIU_DCR_BR: 101883980x1206c68 (tUsb): NEW USB EBIU_DCR_BR: 101883680x1206c68 (tUsb): Config EBIU USB Synchronous Timings0x1206c68 (tUsb): Previous USB EBIU_DCR_BR: 101883680x1206c68 (tUsb): NEW USB EBIU_DCR_BR: 101881620x11d4d70 (tPollVbus): USB connectPullUp = 1But doesn't go as far as the :https://www.eevblog.com/forum/testgear/possible-upgrade-agilent-34410a-to-34411a/threadloll i need to read moreBUT does respond to help>helphelp Print this listioHelp Print I/O utilities help infodbgHelp Print debugger help infonfsHelp Print nfs help infonetHelp Print network help infospyHelp Print task histogrammer help infotimexHelp Print execution timer help infoh  Print (or set) shell historyi  Summary of tasks' TCBsti task Complete info on TCB for tasksp adr,args... Spawn a task, pri=100, opt=0x19, stk=20000taskSpawn name,pri,opt,stk,adr,args... Spawn a tasktd task Delete a taskts task Suspend a tasktr task Resume a taskd [adr[,nunits[,width]]] Display memorym adr[,width] Modify memorymRegs [reg[,task]] Modify a task's registers interactivelypc  Return task's program counterType <CR> to continue, Q<CR> to stop:iam "user"[,"passwd"] Set user name and passwdwhoami Print user namedevs List devicesld [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 tablelkAddr address List symbol table entries near addresscheckStack  List task stack sizes and usageprintErrno value Print the name of a status valueperiod secs,adr,args... Spawn task to call function periodicallyrepeat n,adr,args... Spawn task to call function n times (0=forever)version Print VxWorks version info, and boot lineNOTE: Arguments specifying 'task' can be either task ID or name.value = 1 = 0x1> versionversionVxWorks (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'->

author: coromonadalix
author_rank: Super Contributor
timestamp: November 04, 2022, 10:38:50 am
content: If i search for Agilent KOM PPC405it show a few threads hereThe 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

author: HighVoltage
author_rank: Super Contributor
timestamp: November 04, 2022, 10:45:07 am
content: 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.

author: coromonadalix
author_rank: Super Contributor
timestamp: November 04, 2022, 10:46:40 am
content: yeah thksThat's what i think ....

author: NNNI
author_rank: Regular Contributor
timestamp: July 26, 2023, 11:01:50 pm
content: Quote from: coromonadalix on November 02, 2022, 10:45:12 amI 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?

author: coromonadalix
author_rank: Super Contributor
timestamp: July 27, 2023, 12:43:27 am
content: the shield plate if i remember slide the opposite way of the screwwhen it stop, carefully lift the plate