# Which digipot is this with the markings “AAJU”

I'm porting Marlin to my Qidi Tech 1 and I'm trying to figure out what part this is. The markings on it read "AAJU". I'm pretty sure its the digital pot to adjust the stepper drivers as there isn't a small adjustable pot on them.

• please provide a photo. – Trish Nov 7 '20 at 15:46
• I've added one but the chip is too small to properly photograph. – Zhro Nov 7 '20 at 16:37
• The photo helps a lot (the marking next to it, the position of the chip in general, other chips close to it, the chip itself), but it might help to see also the version number of the board and the complete one, to possibly identify from which board this design derived. – Trish Nov 8 '20 at 10:28

The picture shows, that the marked chip is next to the letters U8 to U12. U is commonly used for Ineparable Assembies, but there are several meanings possible according to the ANSI/IEEE Std 315 (1975). So, let's assume for the moment that this is Assembly 8 to 12.

Note that the X-pot is marked to be down on the right side of each section, right under the sockets, and next to R103 to R107.

The Marking AAJU might belong, according to this reference, to two chips. Both are Voltage uP Supervisory Circuit

AAJU  MAX6339AUT    MAX6339  SOT23-6  Quad Voltage uP Supervisory Circuit
AAJU  MAX6726KASYD3 MAX6726  SOT23-8  Triple Ultra-Low-Voltage uP Supervisory Circuit


The pinout and look of the first chip is very much in line with what I see from the photo:

Sadly, neither a user manual for the board nor the pinout of it seems to be available at the time. My best guess based on these facts is, that it is the Quad Voltage supervisory chip, as the MAX6726 has 8 legs, as the -8 in the entry SOT23-8 indicates.