34465a Troubleshooting  - Page 1
Forum section: electronics / testgear

author: salvagedcircuitry
author_rank: Regular Contributor
timestamp: April 29, 2022, 08:47:36 pm
content: I just picked up a 34465a multimeter on the cheap and on first glance it had very minimal issues. The rear cover plate was missing and there were errors in the error log. The errors were simple - clock battery dead, failed self tests. On initial disassembly, The clock battery was actually missing.I installed a clock battery, ran full self tests and it passed with no errors. I unlocked the firmware for good measure as it was running 2.14.Smooth sailing so far.Then I saw it. There is an indent in the PCB where the bottom chassis screw dug into the PCB. The included screw was too long and the previous owner torqued it down.The mounting hole is in direct line of sight to the PCB underneath the Ethernet jack. Seeing that definitely ruined my day.The good news is that this area of the pcb doesn't look too critical, but it's hard to tell since I could not find a schematic for the 34465a and I don't have access to an xray machine.I noticed that the unit had 2 tiny stickers on the front that labeled it as "bad usb." I tested it with a usb stick and I was able to read / write without issue. I am looking into how to test the usb port for consistency, maybe a sustained large file transfer or file transfer from internal memory to external usb. The last thing I want to do is attempt a usb firmware upgrade and have the unit completely bricked.There's a good chance the screw tore some data-level traces underneath the Ethernet port. There clearly looks like multi-layer damage in that indent.Does anyone have schematics for the 34461a / 34465a / 34470a or an xray machine I can borrowTechnically, this was purchased as a used unit off ebay. I still have a few days left for ebay coverage. I'm just gutted right now. uggh.Here's the direct link to the 34461a multimeter teardown from dave jones:https://flickr.com/photos/eevblog/9088123087/in/album-72157634225126018/I attached the image with the region of interest.Thanks a ton!

author: Venturi962
author_rank: Regular Contributor
timestamp: April 29, 2022, 09:54:14 pm
content: Maybe 'Bad USB' refers to the USB-B port on the back which connects to a computer? That is next to the Ethernet jack.

author: HighVoltage
author_rank: Super Contributor
timestamp: April 30, 2022, 09:28:07 am
content: Maybe you are lucky and there are not too many traces at that spot.Take a bright flashlight and shine through the boards and maybe you can follow some traces and repair them.Or maybe only the "USB bad" is affected and the rest of the instrument is good, it is still a good meter.

author: Dr. Frank
author_rank: Super Contributor
timestamp: April 30, 2022, 09:44:58 am
content: That is obviously the big screw which fixes the case. It's located directly below the LAN plug. So check if LAN is working. That would make sure that the most important interface functionality is given.The USB plug on the backside will be the one which is defective, the USB on the front has nothing to do with that.If the back USB is not working, you do not have direct access to the internal memory, which is a disadvantage, if you want to download stored logged data..I doubt that it's possible to access these over LAN or GPIB.There are SCPI commands to access the internal memory via LAN / GPIB, i.e. the MMEMory subsystem, so you could write a program to perform all actions like a file browser.Anyhow, firmware update to 3.0 or higher is also possible via front USB, and also via LAN,(I have to search for the different methods).The Update Utility lets you select any of these methods.I recommend to do so because then you have the versatile DIG feature.Are any options already installed, especially the MEM option?I would definitely keep the instrument, if LAN is working.FrankPS: schematics are nowhere available. I would also put no effort into repairing the back USB port, just use the instrument as is.

author: salvagedcircuitry
author_rank: Regular Contributor
timestamp: May 02, 2022, 11:41:50 pm
content: Thanks for the input guys! Some good news: I received a 50% discount from the seller and I'm keeping it. A 34465a for $250 is pretty dang good in my book. I did some very rudimentary tests comparing my 34401a to the 34465a and it performs very similarly. From my use so far, I have not found any issues with the front panel USB port.I have not fully disassembled the meter yet, but I've been testing it out using benchvue. The multimeter is picked up via both ethernet and usb by benchvue, but sometimes commands fail and I get errors on the unit. I am literally just combing through options in benchvue so its possible that some of the commands I'm sending are rubbish / meaningless. I need to spend some more time reading up on sending control commands with benchvue.Otherwise, I ordered new bumpers and a rear panel for the meter. Keysight shipped them in 2 days with standard shipping, pretty schmick.I don't believe any options are installed.I am still testing the meter but I plan on updating via front usb port if all goes well. Are there any advantages to installing older firmware than using the latest? I have not seen any modified / hacked firmware for this unit.

author: HighVoltage
author_rank: Super Contributor
timestamp: May 03, 2022, 08:13:39 am
content: You really got a good deal on the 34465AUpdating to the latest firmware (v3.03) is recommended. Plus, starting with Firmware revision 3.00, the digitizing and advanced triggering options are included free of charge.The only pay option you might want to add is the Memory option.

author: Dr. Frank
author_rank: Super Contributor
timestamp: May 03, 2022, 09:11:58 am
content: 250$ is an absolute no-brainer, congrats! Options are not yet installed, that's right.You are already using KS Connection Expert and Interactive IO. The error messages arise from a query (Read Response) after a CLS*, latter does not send data afterwards, so you get a time-out and err -420.Therefore, please make yourself more familiar with SCPI language, and the command set of the 34465A.Backside USB seems to work, but why have you disabled LAN?To test the enabled LAN quickly, you might just connect to its web interface. Simply call its LAN address via your network. If you are able to fully use the graphical UI, then LAN interface is working.Better use Update Utility via LAN to upgrade the firmware, that's more comfortable. The 3.03 will get rid of slavery in your 34465A, and also enable the DIGI option. I recommend the MEM option as well.Frank

author: salvagedcircuitry
author_rank: Regular Contributor
timestamp: May 03, 2022, 04:07:01 pm
content: Thanks for the input guys! When I first opened up the meter I nearly flipped out. The rear bnc's were directly against the sidewall of the box. Luckily the seller at least put a block of foam on the front. I inspected the rear bnc's for damage. Luckilky they look mechanically sound. The under-side solder job looks intact as well, no cracks or seperation.The ethernet was not disabled. I simply tested one interface at a time. I tested usb on it's own. Then I tested ethernet. They perform about the same. It's absolutely possible that communications failed because I am not familiar with the SCPI language and am flying blind.I am going to sit down and spend a day just reading up on this meter so I better understand it. Then I'll update it.When I'm fully comfortable with it, I'll grab the 3446MEMU mem option and a proper PDVS2mini voltage referenceThank again everybody

author: maxwell3e10
author_rank: Frequent Contributor
timestamp: May 04, 2022, 03:59:23 am
content: A philosophical question, what's a fair amount of discount to ask from an e-bay seller if the item turns out to have some problems? I've done it a few times but usually ask for a modest discount and sometimes decline big discounts if I know I can easily fix it. Curious what other people think?

author: bdunham7
author_rank: Super Contributor
timestamp: May 04, 2022, 04:58:39 am
content: Quote from: maxwell3e10 on May 04, 2022, 03:59:23 amIf it is shipping damage on a properly packed item or some unfortunate misunderstanding, I try to work it out fairly and value my time minimally. I also consider what I paid for it. If it is grossly negligent packing, seller misrepresentation (whether due to ignorance or malice) or something like that, I grind them for whatever I can get, even if I got a deal in the first place. I've had a few things where the seller just gave me a full refund and told me not to bother shipping it back.I bought a new BK HV insulation tester real cheap a while back and it was new in box. However, first time I fired it up, the output capacitor shorted. I didn't even complain or ask the seller for a discount off of the $2.86 I had paid. Never sell less-common items on bids!