---
title: "W5500 working only when heated up"
url: "https://maker.wiznet.io/forum/14328"
markdown_url: "https://maker.wiznet.io/forum/14328/md"
type: "Forum topic"
category: "Ethernet Chips"
author: "Ermin Podrug"
created: "2021-08-16T16:26:36+09:00"
last_activity: "2021-08-17T01:27:25+09:00"
language: "en"
views: 354
replies: 1
source: "WIZnet Makers forum (https://maker.wiznet.io/forum/)"
---

# W5500 working only when heated up

## Question

Asked by Ermin Podrug on 2021-08-16 in Ethernet Chips.

Hi,

I’ve designed custom board using W5500 and ESP32, this was upgrade to the previous board that used ATMega328P. Schematic regarding the W5500 stayed the same, only microcontroller changed. Initially i couldn’t read the 25MHz clock, and there would be no communication between ESP32 and W5500. While trying to reflow the crystal circuit, I’ve managed to get the board working but not for too long. As soon as the board cools down it stops working. So the W5500 works only when heated up with hot air.

Thank you for the response,
Ermin

## Replies

### Reply 1 by louis, 2021-08-17

Hello,

I think it’s a hardware fault. I’ll give you a document for your reference.
<https://wizwiki.net/wiki/doku.php/products:w5500:refschematic>

Thank you.

---

Source: https://maker.wiznet.io/forum/14328