---
title: "WIZ550WEB-EVB, analog inputs do not work"
url: "https://maker.wiznet.io/forum/13574"
markdown_url: "https://maker.wiznet.io/forum/13574/md"
type: "Forum topic"
category: "Serial-to-Ethernet & ConfigTool"
author: "wk5000"
created: "2019-11-14T10:55:01+09:00"
last_activity: "2019-11-18T07:02:34+09:00"
language: "en"
views: 433
replies: 3
source: "WIZnet Makers forum (https://maker.wiznet.io/forum/)"
---

# WIZ550WEB-EVB, analog inputs do not work

## Question

Asked by wk5000 on 2019-11-14 in Serial-to-Ethernet & ConfigTool.

Hi,

Analog inputs 0 and 1 do not work.
Inputs 2 and 3 are ok.

Jumpers J27 und J28 are in the right position (temp and trimmer disabled)

Inputs 0 and 1 show fixed values, independent of any external voltage.
Op-Amp U8 seems to be dead?

Or is there any more way to configure Inputs 0 and 1?

Thanks

## Replies

### Reply 1 by irina, 2019-11-15

Hi~

I think you should test about A0,A1.
First, J27 and J28 are connect 1 and 2 with each other.

If Analog signal is correct operation at this situation, U8 seems to be dead.

### Reply 2 by wk5000, 2019-11-15

Thanks.
If I put J27 and J28 in the opposite position, trimmer and temp level are shown correctly.
Thus AD-Converter works, but U8 is dead

### Reply 3 by irina, 2019-11-18 (in reply to reply 2)

Unfortunately, you should be change an U8.
The Part name of U8 is LM358APWR(Dual Operational Amplifiers)
DataSheet Link : [LM358APWR_Datasheet](https://wizwiki.net/wiki/lib/exe/fetch.php/products:wiz550web:wiz550webds_kr:lm358apwr.pdf)

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Source: https://maker.wiznet.io/forum/13574