<p>The picture shows, that the marked chip is next to the letters <code>U8</code> to <code>U12</code>. U is commonly used for <a href="https://electronics.stackexchange.com/questions/25308/what-do-the-pcb-markings-mean">Ineparable Assembies</a>, but there are several meanings possible according to the <a href="http://standards.ieee.org/findstds/standard/315-1975.html" rel="nofollow noreferrer">ANSI/IEEE Std 315 (1975)</a>. So, let's assume for the moment that this is <code>Assembly 8</code> to 12.</p>
<p>Note that the X-pot is marked to be down on the right side of each section, right under the sockets, and next to <code>R103</code> to <code>R107</code>.</p>
<p>The Marking AAJU might belong, according to <a href="http://chip.tomsk.ru/chip/chipdoc.nsf/vc1!readform&amp;view=smd&amp;cat=A&amp;start=5001&amp;count=500" rel="nofollow noreferrer">this reference</a>, to two chips. Both are <em>Voltage uP Supervisory Circuit</em></p>
<pre><code>AAJU  MAX6339AUT    MAX6339  SOT23-6  Quad Voltage uP Supervisory Circuit
AAJU  MAX6726KASYD3 MAX6726  SOT23-8  Triple Ultra-Low-Voltage uP Supervisory Circuit
</code></pre>
<p>The pinout and look of the <a href="http://www.datasheetdir.com/MAX6339+Microprocessor-Supervisors" rel="nofollow noreferrer">first chip</a> is very much in line with what I see from the photo:</p>
<p><a href="http://www.datasheetdir.com/MAX6339+Microprocessor-Supervisors" rel="nofollow noreferrer"><img src="https://i.sstatic.net/jRyFy.png" alt="enter image description here" /></a><a href="https://i.sstatic.net/KeR25.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/KeR25.png" alt="enter image description here" /></a></p>
<p>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 <a href="http://www.datasheetdir.com/MAX6726+Microprocessor-Supervisors" rel="nofollow noreferrer">MAX6726 has 8 legs</a>, as the <code>-8</code> in the entry <code>SOT23-8</code> indicates.</p>

CC BY-SA 4.0
2020-11-08T10:08:45.183Z
2020-11-08T10:38:52.803Z
2020-11-08T10:38:52.803Z
Trish
<p>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 &quot;AAJU&quot;. I'm pretty sure its the digital pot to adjust the stepper drivers as there isn't a small adjustable pot on them.</p>
<p><img src="https://i.sstatic.net/pj1wE.jpg" alt="enter image description here" /></p>

CC BY-SA 4.0
2020-11-07T15:46:04.550Z
please provide a photo.
Trish
CC BY-SA 4.0
2020-11-07T16:37:54.733Z
I've added one but the chip is too small to properly photograph.
Zhro
CC BY-SA 4.0
2020-11-08T10:28:54.770Z
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
<marlin><firmware><stepper-driver>
Which digipot is this with the markings "AAJU"
Zhro
# Which digipot is this with the markings "AAJU"

(Asked by: username_0 on 2020-11-07)

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.

![enter image description here](https://i.sstatic.net/pj1wE.jpg)

**Tags:** marlin, firmware, stepper-driver

> **Comments:**
> **username_1**: please provide a photo.  
> **username_0**: I've added one but the chip is too small to properly photograph.  
> **username_1**: 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.  

---

## 1 answers

### Answer by username_1 on 2020-11-08. Score: 0 | Accepted answer

The picture shows, that the marked chip is next to the letters `U8` to `U12`. U is commonly used for [Ineparable Assembies](https://electronics.stackexchange.com/questions/25308/what-do-the-pcb-markings-mean), but there are several meanings possible according to the [ANSI/IEEE Std 315 (1975)](http://standards.ieee.org/findstds/standard/315-1975.html). 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](http://chip.tomsk.ru/chip/chipdoc.nsf/vc1!readform&view=smd&cat=A&start=5001&count=500), 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](http://www.datasheetdir.com/MAX6339+Microprocessor-Supervisors) is very much in line with what I see from the photo:

[![enter image description here](https://i.sstatic.net/jRyFy.png)](http://www.datasheetdir.com/MAX6339+Microprocessor-Supervisors)[![enter image description here](https://i.sstatic.net/KeR25.png)](https://i.sstatic.net/KeR25.png)

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](http://www.datasheetdir.com/MAX6726+Microprocessor-Supervisors), as the `-8` in the entry `SOT23-8` indicates.


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