ET4401/4090A etc., Bench Top LCR Meters Query?

[Chris56000]

Hi!

Regarding the East Tec LCR Meters and their 4090A/4090B/4090C clones, has anyone determined exactly all the chips that are employed in these instruments?

I know there's one very large QFP device that appears, from all the available pictures I can find, appears to have its number sanded off – has anyone determined what it is?

Chris Williams

[Martin72]

Hi Chris,

I´ve started to make a schematic from a ET4410:

https://www.eevblog.com/forum/testgear/east-tester-et4410-esr-measure/msg4331890/#msg4331890

There are lots of op-amps and cmos switches there.

Pics from the inside:

https://www.eevblog.com/forum/testgear/east-tester-et4410-desktop-lcr-meter/msg4002337/#msg4002337

The µC is an ARM STM32..

[Chris56000]

Hi!

They've clearly not sanded the numbers off on the sample you've posted your pictures from!

Could you email me your pictures please Martin?

PM sent.

Chris Williams