Why does my Thetford porta potty-type toilet need a circuit board to turn on and off the flush moto

Thread Starter

Tonesaul

Joined Dec 13, 2018
7
Hi.
The problem is that the motor stuck on and all that blue stuff files the pan and overflowed...more than once. Found lots of electronics on a board under the on\off flush switch and am thinking about simply sticking a basic on\off switch from batteries to motor terminals. Why not is the question. Why a circuit board with chips and transistors etc? Makes me nervous to bypass it all. Thought I'd check in with someone here first. Thanks
 

jpanhalt

Joined Jan 18, 2008
8,738
If the windshield wipers in a car run on microcontrollers, it is not surprising a porta potty does too.

The problem is that without anything else to go on, what sort of answer do you want? One approach is to "just do it." But that might make a mess. Are there sequential processes, like a motor, valves, fluid dispenser and so forth all acting in an orchestrated sequence? If so, then a simple on/off switch might lead to diminished performance and wasted chemicals.

Can you provide more information and pictures. It is possible the motor stayed on for a reason, such as a stuck valve or sensor or maybe a burned component on the circuit board.
 

Thread Starter

Tonesaul

Joined Dec 13, 2018
7
Hi,
I did take a picture of the circuit board. I'll try and attach. As far as I can tell the micro switch turns on a motor that pumps the liquid from a reservoir into the bowl. I will try bypassing it shortly. Won't have my soldering iron with me till a fortnight's time. I hacked the micro switch off the board and isit made no difference. The pump still switches on the instant you put the batteries back in place.
 

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MrChips

Joined Oct 2, 2009
20,245
If there is no sensor to sense when the bowl is full then it is simply a timed power switch and the circuit is bad.
Here are your options:

1) Get a new potty
2) Replace the board
3) Trouble-shoot the board starting with the driver transistor
4) Replace the board with a heavy duty momentary pushbutton
 

Thread Starter

Tonesaul

Joined Dec 13, 2018
7
Thanks folks. You've put my mind at ease. My wife says there is a slight delay after taking your finger off the button. Momentary push button is the simple solution then definitely. Just didn't realise there was that second delay so wondered what the hell all that circuitry was for. Being a bloke and not wanting to empty the loo so often guess I didn't flush so much.
Thanks again
 

spinnaker

Joined Oct 29, 2009
7,837
If there is no sensor to sense when the bowl is full then it is simply a timed power switch and the circuit is bad.
Here are your options:

1) Get a new potty

Correction. Get a new old tech potty that does not require a freaking circuit board! What is wrong with a potty you have to mannually pump to flush?
 
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