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Keysight 34465A reliability

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nctnico:

--- Quote from: floobydust on April 06, 2022, 05:55:15 pm ---Likely not related to OP's fault, but something to point out (and I do hope I'm wrong here):
TI/Stellaris LM3S1D21 ARM processor is discontinued 2016 and withdrawn from the market due to the flash corruption issues. The parts are a lemon, known about in 2014.
"Flash corruption or device failure may occur at power on"
"Flash memory endurance cycle specification is 100 cycles"
"Flash memory corruption may occur when device is unpowered and stored for several months - Due to the storage oxide thickness and trap-assisted electron tunneling, there are more leaked cell values than originally expected in the Flash design within several months after programming. As a result, the ECC logic is not able to repair all of the errors in the Flash memory. Data derived from customer returns predicts that devices that are left unpowered at room temperature storage for 6 months can result in failure rates of 2000-3000 DPPM per year."
Ref: TEMPEST/INFERNO LM3S Errata Document (Literature Number: SPMZ861)

Bench multimeter product line 34461A, 34465A, 34470A use this MCU not as the main front panel processor but I think it's the Inguard processor.

If this is a real problem, silicon revisions need to be confirmed it's all 130nm parts, Keysight should be offering free extended warranty. It would be a massive debacle.

--- End quote ---
I'm afraid you are not wrong. It is a good find though so I appreciate you taking the trouble for digging this up. There is nothing to be found on TI's website about these microcontrollers nowadays. As if they never existed!

My 34461A also has the LM3S1D21 microcontroller revision A2 which is affected by the flash corruption problem. A way around it, is to leave the device on for at least 24 hours to give the internal flash controller the chance to fix the bits that have gotten corrupted. However, that system isn't failsafe as well and can actually corrupt data which was good. On top of that it is hard to tell whether a corrupted flash is signalled at all and how this affects measurements. It could be that the software continuous on with bad data affecting the measurement results.

All in all these units have a ticking time bomb inside them.  :palm:

HighVoltage:

--- Quote from: nctnico on April 07, 2022, 11:58:10 pm ---
All in all these units have a ticking time bomb inside them.  :palm:

--- End quote ---

This is really bad news, if true. I have many of the 34461A in the field with customers.
Do we know when Keysight switched away from the LM3S1D21 microcontroller to a different one?

Kleinstein:
I have a teardown photo (should be somewhere here in the forum) from an 34461, that shows a TM4C129 for the inbound µC. So chances are they have different versions. With the chip getting obsolete they kind of need to have a replacement. Given the problems I don't think KS would still use any NOS parts from an EOL buy.

There should be a flash checksum test as part of the POS. So flash corruption would likely be catched after power on. Ideally one would even get a specific error code for a checksum failure.
Chances are that the code for the actual measurements is only a small part of the code and a bad bit is more likely to cause a crash than a wrong result.

hpw:

--- Quote from: floobydust on April 06, 2022, 05:55:15 pm ---Likely not related to OP's fault, but something to point out (and I do hope I'm wrong here):
TI/Stellaris LM3S1D21 ARM processor is discontinued 2016 and withdrawn from the market due to the flash corruption issues. The parts are a lemon, known about in 2014.
"Flash corruption or device failure may occur at power on"
"Flash memory endurance cycle specification is 100 cycles"
"Flash memory corruption may occur when device is unpowered and stored for several months - Due to the storage oxide thickness and trap-assisted electron tunneling, there are more leaked cell values than originally expected in the Flash design within several months after programming. As a result, the ECC logic is not able to repair all of the errors in the Flash memory. Data derived from customer returns predicts that devices that are left unpowered at room temperature storage for 6 months can result in failure rates of 2000-3000 DPPM per year."
Ref: TEMPEST/INFERNO LM3S Errata Document (Literature Number: SPMZ861)

Bench multimeter product line 34461A, 34465A, 34470A use this MCU not as the main front panel processor but I think it's the Inguard processor.

If this is a real problem, silicon revisions need to be confirmed it's all 130nm parts, Keysight should be offering free extended warranty. It would be a massive debacle.

Front Panel processor ST SPEAr320S-2 is obsolete as well, but I did not dig into its issues.

--- End quote ---

This rings me a bell  ::)

Does this means also, that the Wave Generator Trueform models 335xx & 336xx uses equal processors?

Hp

TheSteve:

--- Quote from: hpw on April 08, 2022, 09:24:42 am ---
--- Quote from: floobydust on April 06, 2022, 05:55:15 pm ---Likely not related to OP's fault, but something to point out (and I do hope I'm wrong here):
TI/Stellaris LM3S1D21 ARM processor is discontinued 2016 and withdrawn from the market due to the flash corruption issues. The parts are a lemon, known about in 2014.
"Flash corruption or device failure may occur at power on"
"Flash memory endurance cycle specification is 100 cycles"
"Flash memory corruption may occur when device is unpowered and stored for several months - Due to the storage oxide thickness and trap-assisted electron tunneling, there are more leaked cell values than originally expected in the Flash design within several months after programming. As a result, the ECC logic is not able to repair all of the errors in the Flash memory. Data derived from customer returns predicts that devices that are left unpowered at room temperature storage for 6 months can result in failure rates of 2000-3000 DPPM per year."
Ref: TEMPEST/INFERNO LM3S Errata Document (Literature Number: SPMZ861)

Bench multimeter product line 34461A, 34465A, 34470A use this MCU not as the main front panel processor but I think it's the Inguard processor.

If this is a real problem, silicon revisions need to be confirmed it's all 130nm parts, Keysight should be offering free extended warranty. It would be a massive debacle.

Front Panel processor ST SPEAr320S-2 is obsolete as well, but I did not dig into its issues.

--- End quote ---

This rings me a bell  ::)

Does this means also, that the Wave Generator Trueform models 335xx & 336xx uses equal processors?

Hp

--- End quote ---

From memory they use a different processor part #.

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