"Stuck Thermostat"
Luke,
I commend you for your electronic efforts ! I did not realize that you are an 'IT' person. But, this is a great cause...to help reptiles ! As with most problems, patience and determination will preservere, and in the end
you will remember this circuit. We will make this WORK!
I used the UAA1010, not the new guy(UAA2036) But similar. From my previous advice, the use of the 100K pot was used to simulate the temperature set-point. The set point is derived from the 47K and 100K(ntc) resistor series. First we will start with the basics of debugging prototypes. I am not sure if you are using a breadboard or the wiring is point to point.
With the circuit powered "OFF", do the following:
Steps 1..7
1. With every connection, ohm or 'beep' out the connection from the part ie. resistor,pot, diode to the pin on the IC(integrated circuit), THEN
HIGHLIGHT with a highlighter.
This will save countless hours in open or poor connection problems !
2. With your DVM, measure the value of resistors in ohms, And verify
that the value is correct on the schematic.
3. If using electrolytic(like you have 100 uF) or polarized capacitors(tantalum) insure that the positive side is connected to the positive terminal. for the 100 uf , the band or (+) is marked AND should be connected to pin 7 or Vcc. Diodes too.
From your scanned schematic, change 3 things.
4. Remove Rout(60 ohms and Led , and jumper from pin 6 to the 'GATE" on the triac.
5. Jumper Pin 2 to Vcc(GND).
6. Change Rs from 39K to 18K , 2W.
7. Make the changes to your schematic.
This strips the circuitry down some and Rs may have been to high a value.
Check the new schematic as in steps 1..3
8. With the 100K pot connected from Vref to Vcc, disconnect the wiper.
Power up the circuit and adjust the wiper to about - 1V , power down and reconnect the wiper to pin 3. Let the DVM be connected to the wiper or pin 3.
Why ?
This insure that the voltage is NOT set to high as to "Lock - Out" the safety feature.
9. Power -up and slowly adjust to > -2.75V, and allow to settle for 60 sec.
and 'treak' a little more.
Do you get the light(load) to switch from "OFF" to "ON" ? Any pulsing ?
Fred