Datron 4000A photographs - Page 1
Forum section: electronics / general

author: Jay_Diddy_B
author_rank: Super Contributor
timestamp: August 13, 2025, 08:16:24 pm
content: Hi group,I am going to share some photographs of a Datron 4000A Autocal Standard. This unit has DC volts, DC current and resistors.I bought this unit locally. It looked clean on the outside, but when I got it home I found that the Lithium Thionyl Chloride battery had leaked and damaged a couple of the PCBs.Cover OffRemoving the top cover reveals a a metal shield with a guard panel attached to the underneath.BoardsThe boards are arranged in a card cage. The ejector tabs are color-coded. There are a couple of empty slots. I assume that these are for similar products with AC options.Power SectionThe power supplies and power amplifiers are located in the back of the unit.Jay_Diddy_B

author: Jay_Diddy_B
author_rank: Super Contributor
timestamp: August 13, 2025, 08:24:49 pm
content: Hi group continuing the photographs:Digital PCBThis board contains the microprocessor, and battery backed up SRAM.Digital Board SRAMThis is the board in its original configuration. I have changed a lot of the discrete components.Digital Board with FRAM modificationI have replaced the 5101 SRAMs with a FRAM. The battery is not needed now.Regards,Jay_Diddy_B

author: Jay_Diddy_B
author_rank: Super Contributor
timestamp: August 13, 2025, 08:31:28 pm
content: HiAnalog Interface PCBThis board was also damaged by the battery leakage. I rebuilt the left-hand end of this board.Analog Interface (Left)Some PCB trace connecting the resistor array were destroyed. I replaced these tracks with thin wires.Crusty ChipThis photographs shows what the battery leakage can do to a chip. If you need a reason to install FRAM and remove batteries, this is it.Regards,Jay_Diddy_B

author: Jay_Diddy_B
author_rank: Super Contributor
timestamp: August 13, 2025, 08:52:36 pm
content: Hi more pictures:Reference Divider BoardThis board contains the reference assembly, PWM divider (125 Hz) and 7-pole Bessel FilterReference assemblyThe reference uses two strings of four reference diodes that were carefully selected at the factory so that the TCs cancel. The output of the board is between 20.3 and 20.9 volts. In addition to the two Molex connectors there is a wire connecting this assembly to the PCB.Reference diodesJay_Diddy_B

author: Jay_Diddy_B
author_rank: Super Contributor
timestamp: August 13, 2025, 08:56:58 pm
content: Hi,DC PCB assemblyOhms and mAJay_Diddy_B

author: TheDefpom
author_rank: Frequent Contributor
timestamp: August 13, 2025, 09:40:01 pm
content: I’m interested in that FRAM module, I have a 4700 which I would like to do this to, I would have to check if the same SRAM setting is used, it probably is, might even be the same board. I did a few videos on the 4700 when I repaired it, might be worth a look to see if the boards are indeed the same for the same functions.I had to replace every single electrolytic cap and every 25v tantalum (upgraded to 35v, as they kept shorting out!)

author: Jay_Diddy_B
author_rank: Super Contributor
timestamp: August 14, 2025, 12:02:58 am
content: TheDefpom and the group,I looked at the video. It looks like yours has a 24-pin RAM, probably a 6116:It should be possible to design a similar module for the 6116.The 2x 5101 may fit 1061A or 1062 DMMs depending on the vintage.Regards,Jay_Diddy_B