GI ER3400 earom - Page 1
Forum section: electronics / repair

author: Daxxin
author_rank: Regular Contributor
timestamp: May 09, 2019, 09:54:31 am
content: Its possible to clone the content with a programmer?Cant find much info with google

author: picburner
author_rank: Frequent Contributor
timestamp: May 09, 2019, 07:26:02 pm
content: Some time ago I built this adapter to read and save the contents of the er3400 of my Solartron 7081.You must select 2716 (or another 2K eprom in the eprom-programmer) and read 1KByte only.Of course only the first data nibble is valid (D0-D3).I have never ventured into writing this old earom with an eprom-programmer.

author: JFJ
author_rank: Regular Contributor
timestamp: May 09, 2019, 10:06:38 pm
content: Quote from: Daxxin on May 09, 2019, 09:54:31 amI've never encountered an off the shelf programmer that could generate the -30V that has to be applied pin 1 (Vgg) of an ER3400 during write mode. So, using a standard programmer to write a copy to another ER3400 may not be straightforward.Quote from: picburner on May 09, 2019, 07:26:02 pmI also used an EPROM programmer to backup the contents of the ER3400 from my Solartron 7081. Instead of building an adapter, I just plugged the ER3400 into a breadboard, and used jumper leads to connect it to a 24-way turned pin DIL socket (configured as a 2716 EPROM), which was then inserted into my programmer's ZIF socket. The -12V Vdd voltage was provided by an external bench power supply. I didn't bother with a -30V supply, because the ER3400 can be operated with Vgg tied to Vss (+5V) in read mode.Incidentally, the voltages supplied to pins 1 and 2 of the ER3400 socket in your circuit diagram appear to have been transposed:

author: picburner
author_rank: Frequent Contributor
timestamp: May 10, 2019, 05:39:37 am
content: Thanks for the warning: I corrected the error in the schematic.In fact even my 'adapter' is very basic as it is a copy job I would have done only once.

author: Daxxin
author_rank: Regular Contributor
timestamp: May 10, 2019, 06:08:14 am
content: Thanks for the answer but another question how do you planned to restore your backup in case need?

author: Chris56000
author_rank: Frequent Contributor
timestamp: May 10, 2019, 07:19:47 am
content: Hi!I can't seem to locate it just at the moment but there is an easy–to–build ER1400 programming adaptor circuit built out of a handful of cheap components – you might be able to use this!Chris Williams

author: picburner
author_rank: Frequent Contributor
timestamp: May 10, 2019, 02:47:01 pm
content: Quote from: Daxxin on May 10, 2019, 06:08:14 amGood question!Indeed, if reading the device is not so complicated, to program it it is necessary to build a dedicated programmer that executes the erasure and programming sequence described in the datasheet.As already mentioned by JFJ, finding a commercial programmer able to program this device is difficult due to the -12V and -30V voltages required.I hope I don't have the need to program this device soon...

author: Daxxin
author_rank: Regular Contributor
timestamp: May 10, 2019, 04:32:53 pm
content: Yes maybe external power supply , then i seen there 2 different version of ER3400 and ER3400H look like the second one need -35v or -37vto write the content .

author: picburner
author_rank: Frequent Contributor
timestamp: August 12, 2020, 04:20:38 pm
content: After a long time, taking advantage of the fact that I found several Arduino uno in a flea market, I decided to make a small programmer dedicated to the earom GI ER3400.Basically I reworked a Erik van Zijst work (which you can findhereandhere) creating a Arduino shield capable of reading, writing, erasing and blank checking the earom.Unlike Erik, I used a 74HC4040 as address register because I had some in the drawer.Communication between Arduino and the computer takes place through a program written in Python.The changes I made to the Erik's software are very crude (certainly someone will be able to rewrite everything in a more elegant way)however the programmer works and for me this is enough.The pics are related to an old shield with external -30V power supply.The new schematic instead incorporates a DC/DC converter that generates the -30V on board, however it is necessary to supply the Arduino uno via an external power supply (the USB cable is not able to supply the necessary current).

author: free_electron
author_rank: Super Contributor
timestamp: August 12, 2020, 05:04:47 pm
content: YOU CUT A TEXTOOL SOCKET IN HALF !!! now i have to go sit in a corner and cry for a few hours.... Please tell me it was a chinese knock-off (probably. the 3M doesn't look right ..)

author: picburner
author_rank: Frequent Contributor
timestamp: August 12, 2020, 05:17:18 pm
content: Of course it was a Chinese Textool! I would never do such thing on a genuine 3M.The fact is that I had ordered an 'ad-hoc' 24 Pin wide textool but I got the 300mils one! So I had to commit the crime!

author: Floejoe
author_rank: Newbie
timestamp: December 05, 2020, 04:45:57 pm
content: Great project!Thank you for posting this, it worked an absolute treat and helped me out with repairing some old Marconi 2305 modulation meters. It was very straight forward to build and although I had a few issues with the Python script I was able work around these by using Anaconda instead (missing Redline module issue).Joe,

author: picburner
author_rank: Frequent Contributor
timestamp: December 19, 2020, 08:34:30 am
content: I am glad that my work has been useful to someone else besides me.Of course it is a very niche application, good only for owners of some Solartron and Marconi instruments.

author: meandeev
author_rank: Regular Contributor
timestamp: August 16, 2021, 07:25:30 pm
content: Hello,do you have the pcb-layout (even as pdf), so that one sent it to a pcb manufacturer? That would be really nice!

author: picburner
author_rank: Frequent Contributor
timestamp: August 17, 2021, 03:54:04 pm
content: Attached there are all the files (schematic & pcb) made with Altium.But keep in mind that I made the pcb so that it can be made at home with the photoengraving technique.It was not designed to have it made by a pcb manufacturer, in my opinion it would be better to completely remake it in this case

author: meandeev
author_rank: Regular Contributor
timestamp: August 18, 2021, 03:13:21 pm
content: Thank you for the files! Can anybody convert these to gerber (I don´t have any layout program).

author: DonBox
author_rank: Newbie
timestamp: October 09, 2022, 02:06:05 pm
content: My solartron 7081 also reports error 'NVM FAIL'.

author: picburner
author_rank: Frequent Contributor
timestamp: October 11, 2022, 07:53:10 am
content: The Solartron 7081 earom contains a second copy of the configuration data inside.If the contents of the main memory block are only corrupted (and if the second copy is intact) and the earom is not damaged at the hardware level, you can try to restore the contents: There is an explanation of the procedure to be followed in the service manual of the instrument.

author: stoka22
author_rank: Newbie
timestamp: October 28, 2022, 07:34:06 pm
content: Dear friend. i built the circuit but i can't write the er3400 eaprom. Do I need to modify the program code? could you send a sample for writing. ThanksProblem is:'diff' is not recognized as an internal or external command,operable program or batch file.

author: Jay_Diddy_B
author_rank: Super Contributor
timestamp: September 12, 2025, 02:22:19 pm
content: Hi picburner and the group,I know that this an old thread, but I feel I should keep the information on the ER3400 in the same thread.I have found the ER3400 EAROMs in Solartron 7081 DMM and Marconi 2018, 2018A, 2019 and 2019A signal generators.The ER3400 is old technology and use -12V and -30V. Most, if not all, modern programmers do not support these negative voltages. As other have found it essential to build a special programmer for these devices.I have taken the schematic that was shared by picburner in this thread and designed and built a version of the project.I have done some initial tests using the software in this message:https://www.eevblog.com/forum/repair/gi-er3400-earom/msg3185294/#msg3185294It appears to be working properly. I have not tested my hardware yet with a precious ER3400.I will share more after I have confirmed that it works properly.I am building this to backup the calibration in my Solartron 7081.Regards,Jay_Diddy_B

author: Jay_Diddy_B
author_rank: Super Contributor
timestamp: September 13, 2025, 01:26:38 am
content: Hi group,I have done some testing and I believe that the schematic and the PCB are correct.Here are the files. I have attached a pdf of the schematic and a zipfile that can be sent to your favorite PCB vendor.Thanks again to picburner. The software works without any modifications.Regards,Jay_Diddy_Ber3400_prog.zip(97.21 kB - downloaded 3 times.)er3400_prog_sch.pdf(75.05 kB - downloaded 6 times.)