Need help with PCB based circut

Thread Starter

mongoose711

Joined Sep 4, 2009
7

beenthere

Joined Apr 20, 2004
15,819
Use a meter and yur eyes - trace the foil from the button to an IC. Get the data sheet for the IC. Once you have figured out what the IC does, you can determine if that latched the PB signal, or debounced it and sent the clean signal to another IC. The you get that IC's data sheet.

It is very likely that the one and only IC of importance is a microprocessor. The all the business is done according to the program. You usually can't get at the internal code.
 

Thread Starter

mongoose711

Joined Sep 4, 2009
7
let me give you guys a little more detail. I don't need to find the section of the circuit that causes the latching, I need to find the latched section that activates/ deactivates the relay.
 

CDRIVE

Joined Jul 1, 2008
2,219
let me give you guys a little more detail. I don't need to find the section of the circuit that causes the latching, I need to find the latched section that activates/ deactivates the relay.
Thank God, I'm not going blind. There really is a relay there! I feel better now.:D
 

CDRIVE

Joined Jul 1, 2008
2,219
let me give you guys a little more detail. I don't need to find the section of the circuit that causes the latching, I need to find the latched section that activates/ deactivates the relay.
Most manufacturers silk screen the pin-out of their relays on the case. Did you look? If not, here's a clue.. The control portion (coil) of the relay won't be going to your load. ;)

Edit: I forgot to mention that unless the controlling device has an integral protection diode you should see a diode on the board. The coil will be across the diode.
 
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Thread Starter

mongoose711

Joined Sep 4, 2009
7
Aside from the relay, there must be a pushbutton or switch...


The manual override button is a push only button that de/activates the latching circuit that in turn activate the relay. the relay is a 30a 240v ac rated relay which is controlling 120v ac. the coil is also 120v ac. 3v power is supplied to the PCB via 2 AAA batteries. there are 2 transistors that appear to be linked to the relay along with 4 resistors, a diode and a ceramic disk cap.
 
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