7805 running hot but clock is running fine

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1 year 7 months ago #9189 by Pjotrke
The ESP gets scorching hot very quickly. Too hot to touch.

The current is about 260mA without the ESP and 700mA with the ESP connected. The module connected to the ESP also gets very hot and has colouration on one of the solder joints.

See photo:
abload.de/img/2018-11-0212.38.12dpfdr.jpg

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1 year 7 months ago #9191 by Ty_Eeberfest
700mA is definitely a problem. The entire circuit including the WiFi module should draw no more than about 300mA.

That discolored solder is on the 3.3v regulator that powers the ESP. Is the regulator the thing that's getting hot on that board or is that discoloration possibly just flux that didn't get cleaned off?

What happens if you plug the interface board (the one in your picture) into the clock but don't plug the ESP into it? Does the current stay around 260mA or does it jump up?

Thinking back a long time, I recall I have had 2 ESP-01 modules go bad in a similar way: extremely hot and would not work at all. Both happened on the same day. I was working with them on a breadboard with 5v and 3.3v rails. At the time I just thought that I'd hit them with the wrong voltage on their Vcc pins, replaced them and forgot about it. You might want to measure voltage between Pin 8 and Pin 1 on the 8-pin connector with ESP unplugged from it. If it is over 3.4 volts then the regulator on the interface board is bad.

In case you need it here's a ESP-01 pinout I recently posted for someone.
www.tubeclockdb.com/component/kunena/12-...m.html?start=10#9157
Ignore the photo, scroll down a bit to the diagram.

Look into it later when the dust is clearing off the crater.

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1 year 7 months ago #9193 by Ian
And just one other little question: The regulator with all the flux on it is a 3V3 one? I think it is, but the picture is just not quite clear enough for me to be 100% sure.

If you measure the voltage (with the ESP not in the socket) it is 3V3, right?



Measure at the middle pin of the regulator.
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1 year 6 months ago - 1 year 6 months ago #9273 by Pjotrke
Sorry for the infrequent updates. Life gets in the way of hobbies sometimes.

@Ty_Eeberfest, The regulator itself gets hot indeed. The colouration cleans of quite easily so it seems to be excess flux. I measured 260mA with the regulator connected.

No heat when the ESP module is not connected. Voltage at both pin 8 and the middle pin of the regulator is 3,29V so that seems ok.

Both regulator and wifi module came with the All in One kit. At the time of ordering the kit I was not confident enough to buy my own components. So no crazy unknown components in play;)
Last edit: 1 year 6 months ago by Pjotrke.

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1 year 6 months ago - 1 year 6 months ago #9275 by Ty_Eeberfest
Looking at that info I'm pretty confident that the ESP itself is bad. What I'm not seeing is anything that would have caused it to fail.The supply voltage looks good, and even if the level shifters on the serial lines had totally failed it's not likely to damage the ESP. {I have an ESP programmer that (incorrectly) puts a 5 volt signal on the ESP's serial lines and it has never killed an ESP}

Best solution IMO is to get a new ESP-01 either from Ian or from Ebay / Ali / whoever. Because your clock is Modular Rev 2 you'll have to get with Ian about obtaining the old Rev 2 code for the ESP.

Look into it later when the dust is clearing off the crater.
Last edit: 1 year 6 months ago by Ty_Eeberfest.

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1 year 6 months ago #9278 by Ian
It sounds really like that is the problem. Please ping me wia email and I'll get a replacment on the way to you.

Ian

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