Help modifying timer circuit to have faster dwell

[211]

I have an electronic timer relay from Omega (Omega Part No. FSV-AT2000).

It has variable on/off controls but I need the dwell time for the OFF circuit to be shorter in duration. Currently the minimum off time is 30 seconds which is waaay too long. I need it somewhere around .5/sec.

I'm pretty rusty with my electronics but I figured it may be as simple as replacing a resistor with a different value.
There's two pots; one for off, one for on. I thought the resistor to the center tap of the OFF pot may be the one to control the timing (R/C time circuit?).

anyone care to have a look at the attachments and take a guess which components I can modify to speed up the off circuit?

Looking at the PCB the OFF pot is the one on the right. You'll notice also, on the far right of the pcb next to the pot (above the green led) there's two resistors soldered in series. This goes to the center tap of the OFF pot.

 

[dr pepper]

The 4541 on the pcb is a programmable timer.
Pins 1 to 3 are connections for the built in oscillator, the timing cap is on pin 2, if you reduce this then the minimum time duration will decrease.
There are loads of other factors to take into account, but you could try a smaller cap, say 5 to 10 times less capacitance and see what happens, there will be a limit as the chip has minimum cpacitance and max frequency limits.

 

[211]

The 4541 on the pcb is a programmable timer.
Pins 1 to 3 are connections for the built in oscillator, the timing cap is on pin 2, if you reduce this then the minimum time duration will decrease.
There are loads of other factors to take into account, but you could try a smaller cap, say 5 to 10 times less capacitance and see what happens, there will be a limit as the chip has minimum cpacitance and max frequency limits.

Great, thank you!
I'll give that a try. Last night I let the smoke out of this thing while trying to read voltages while it was operating... I'll need to order another one .
Its for work so no biggie, I'll just put in a purchase request...

 

[ronv]

What on time are you looking for??

 

[211]

What on time are you looking for??

The range of ON adjustment is fine as-is.
Its the OFF adjustment I need to speed up. Currently its adjustable from .5min to 45min.
I need the adjustment to be somewhere in .5/sec range (+/- a few seconds)

 

[ronv]

Just speeding up the clock will shorten both (I think). Not knowing the whole circuit makes it difficult. Let me look some more at the chip.

 

[ronv]

Have a look at the OMRON site. A bit expensive but they have all types.

https://www.ia.omron.com/product/99.html

 

[Mr RB]

...
Looking at the PCB the OFF pot is the one on the right. You'll notice also, on the far right of the pcb next to the pot (above the green led) there's two resistors soldered in series. This goes to the center tap of the OFF pot.

It's probably that simple. Since the pot and series resistors obviously sets the "off" time then using lower value resistance will proportionately reduce the "off" time.

You maybe able to just lower the series resistor value, but worst-case you might have to lower that AND the pot value by changing the pot as well.

 

[dr pepper]

That ic is a programmable timer, I dont think theres a seperate on and off time within the IC, the designers might have used a trick and change the osc speed depending on the state of the outputs by using a diode or something, romans comments still apply this being the case however finding the actual caps might be a little trickyer.

I've seen similar devices on auto drain valves for emptying water from compressor air receivers.