E3631A firmware version 1.6

[vtp]

Has anyone got the firmware in subject line to upload/attach/email/etc?

I have a couple of these supplies, one with inguard MCU that is silent and other working but with a little noisy readback. Both are with FW1.4 in the inguard MCU.

However, in the (almost) working one the 300 mV offset when a channel is turned off is getting on nerves. That is what the FW1.6 is supposed to fix.

The (now almost) working one was quite a fix. Bought it as "does not turn on" - well of course it would not as there was no fuse.

[vtp]

To update this, I got the faulty supply working for now.

There were two faults: U15 SRAM on top board was faulty and resulted in MCU reseting itself continuosly. This is why the main MCU was not running and there was no display and no beep when powering up.

After the MCU was back in business the 6V output was railed. Root cause was U21B with the following voltages in its pins:

pin 5 (+) = -0.288V, pin 6 (-) = -0.022V, pin 7 (output) = 13.91V. LM339 and the rest connected to this looked ok so pretty obvious, eh?

Replacement of U21 with LM358 as was the original IC there cured the 6V section.


There are at least two different HW versions of this supply. Both I have open at the moment seem to be pre-year 2000 or so and have some differences to the newer version schematics. For example, net "A" on top board is connected to GND(A) whereas in the newer supply it is provided from DAC. U21 on the bottoms board is given as TL072 in new schematics, old supply had LM358.

+-25V bias supply bulk capacitors (C44, C45) seem to run quite hot. I have not removed and measured these yet as but I suspect they have been cooked by the adjacent heatsink and being on top of the casing. Finger test puts the temperature to around >= 40 degC with lid open and in normal ambient room temperature.

As for capacitor replacements, I made this list (Mouser order codes):

Code: [Select]

647-UVR1V471MPD		470u 25V (->35V due I_ripple)
647-UPJ1H471MHD 	470u 50V
661-EKMGG500ELL102MK	1000u 50V
647-UPS1J102MHD1AA	1000u 63V
598-SLPX333M025E9P3	33000u 16V 30x50x10 snap-in
80-PME271M610MR30	100nF 275V X2 P=20.3mm

The list has been compiled by checking original capacitor data for ripple current rating and subsituting currently available capacitor with equivalent or slightly better Iripple in equivalent package size. The last one on the list is replacement for X2 cap on bottom board. It is already cracking open so I am not waiting for the fireworks to begin.

I also got FW 2.1 from a friendly forum member but it will result in error codes 741, 745 and 746 meaning that the supply would need be re-adjusted.

[openloop]

In similar situation and got some questions:
Did 2.1 firmware worked in units which previously had 1.4 installed (i.e. older version units)?
Did it help with negative biasing of switched off output rails?
How can I too get my hands on that firmware file?

Thanks!

[Micke]

I have upgraded two E3631A with FW v2.1 without problems.
I have read about the incompatibility between old HW and new FW, so I was mentally prepared it could be problem   
I think the old FW was something like v1.4 (or even older like v1.2).
I put the old EPROM in a small plastic bag and strapped it with a cable tie inside unit, in case of downgrading in the future...
Yepp, the output bug disappeared according to this service note: http://literature.cdn.keysight.com/litweb/pdf/E3631A-04C.pdf
I can E-mail FW v2.1 to you, send PM!

[z01z]

If someone needs the 1.5 firmware, send me a PM!
The output bug seems not to be present on this version either.

[skripach]

Can I download firmware somewhere for my E3631A power supply? Or buy a preprogrammed U14 chip?

Thanks!

[Samogon]

I proly have one, will see tomorrow when back to computer

[matches]

Hi all,

thanks to helpful mebers Micke and z01z for the firmware. With both V1.5 and 2.1 I hopefully can play around in case of incompatibilitys.

It will be my 1st EPROM to program, so I have some questions.
How did you programm the chip? I'd try the TL866 the TMS27PC020 is in the support list (http://www.autoelectric.cn/minipro/MiniProSupportList.txt)
Of course back up original and UV Erase bevore writing.

The Service Manual lists a U14 as TMS27PC020-150FML. Could this be a typo or something? I can only find TMS27PC020-15FML.
In the case I break it, it would be nice to know if and where to find a replacement.

Regards

[z01z]

The -150 could be an older numbering or a typo, it should be the 150ns version.

The programming is easy, it's just clicking in the software. You can select the make and the type in the software.
You'll also need a suitable PLCC adapter for the programmer. Mind the orientation when inserting the adapter.

If it's a real EPROM (ceramic body, small glass window under which the chip is visible), as you noted, it must be erased first with UV light. You'll have to remove the sticker and put it back after the programming.
If it's an OTP version (plastic body without the window), then you'll need another memory.
These EPROMs can usually be replaced with FLASH memories. I've used the SST39SF020A-70 in another instrument, they are mostly pin compatible. It must be checked that the /PGM pin (#31) is not grounded, as it is the /WE pin for the flash version.

If I were you, I'd get one of these flash memories and keep the original as a backup, but this is just my preference.

[matches]

OK, thanks for the advice.
Originally pin 31 is not connected. I must check on the board, maybe tie it to +5 V.

I ordered the last flash in stock and a TL866 ii Programmer with a bunch of adapters (including PLCC32).
From the part number it seems HP fitted a non erasable PROM. It does not have a window.

I scored a nother E3631A, this one has FW 2.1 already. So I can play around and also check for hardware differences.
One of them goes to a friend.

Regards

[z01z]

According to the service manual, pin 31 is connected, to the /WR pin of the uC.
This is probably OK though. There is no reason to do write operation to the EPROM address range. Moreover, a simple write instruction won't overwrite the flash, a specific sequence of write instructions are needed for a write or erase operation.

[matches]

Ahh, OK. As a part of software write protection.

So I'm just waiting for the programmer to arrive...

[z01z]

Apparently the flash works fine in the place of the OTP EPROM, I've just tested it.

[matches]

Yes it worked for me as well. Thanks for the effort and the advise 

After the update I got the following three errors:
1.   +741,"Cal checksum failed, string data"
2.   +745,"Cal checksum failed, DAC cal constants"
3.   +746,"Cal checksum failed, Readback cal constants"

So I did a calibration with software adjustment. Also I checked before and after the performance.
Before was way off. An output of 25 V gave a reading of 21 V, 1 A programmed supplied only 600 mA etc.
After adjustment the worst point uses about 20 % of the read back spec and 13 % of programm accuracy spec.

So thanks again. Before I found this thread I was under the impression the firmware could not be upgraded.

[NickyDoes]

I have upgraded two E3631A with FW v2.1 without problems.
I have read about the incompatibility between old HW and new FW, so I was mentally prepared it could be problem   
I think the old FW was something like v1.4 (or even older like v1.2).
I put the old EPROM in a small plastic bag and strapped it with a cable tie inside unit, in case of downgrading in the future...
Yepp, the output bug disappeared according to this service note: http://literature.cdn.keysight.com/litweb/pdf/E3631A-04C.pdf
I can E-mail FW v2.1 to you, send PM!

Keysight's CDN doesn't deliver URLs for the long term. Here's one that might be a bit more static:
https://hpwiki.mcguirescientificservices.com/_media/service_notes:e3631a-04c.pdf