Why are circuit boards green? - Electronics - Others

I agree that it sounds like a circuit board problem. So far as I'm aware, shutting off the power and turning it back on should cause the furnace to reset.


But wait and get some additional opinions on this oddball symptom would be my suggestion.
Thanks guys! The Thermostat is applying power. Both limit switches OK. The 2 microswitches attached to the air pressure lines are OK except one stays closed & one open sensing fan air I guess. Zero voltage read between green & white 120VAC input wires. I don't know what else to check. The darn circuit board will not reset and LED gives 2 flashes for lockout, and it means TOTAL LOCKOUT. Could you guys give me an idea how to go about buying a board to try? The only place near me just about doubles the price unless you are a HVAC company. Do I need to replace the part of the board that says "White-Rodgers" on it or just the green circuit board. Thanks again for helping.
Checked for thermostat voltage to Red & W1, checked limit switches, checked for 0 volts between green & white line input voltage, checked for loose connections. Red LED continues to flash 2 times after power recycled for reset.
Gas valve & igniter receive no power. I don't know what else to check. Does anyone have any more ideas to prove circuit board is bad?


My Trane furnace model is XV80, model # TUD100R9V5H6. If circuit board, do I replace the white box labeled "White-Rodgers, Model 50A51-507" or just the small green circuit board labeled "American Standard 21C148501P01?


I appreciate any more help you could give me including where to buy the board.
Thanks! Mickey

Hello Sagar,
green led means tv powered on and status ok.
Red blinking light almost always means defect, overcurrent or overload.
6 blinks for Sony lcd flat tv means trouble in backlight circuit, or backlight inverter (backlight illumination or lighting makes your tv screen visible).
common problems in the inverter circuit, which drives the backlight, or shorted drivers, or short-circuit transformers or open circuits.
You should find the problem in the inverter circuit, or in the power supply board or in the main board.
Also look for bad capacitors (electrolytic caps) which are bulged and swollen on top.
Decoupling plugs from printed circuit boards can help you in finding the problem board by elimination method.
If you power up the set after unplugging certain plugs on f.e. the inverter board , this could result in getting a green power led and concluding that this board is faulty.

succes,
Walter from Antwerp, Belgium.

Is there any problem with it?? I think you may be referring to the LAN adapter's blinking green light, if if is blinking while the computer is on and an ethernet cable is plugged in it is perfectly normal... otherwise please elaborate on the problem.

Red goes to MP and black to MN

you have a low amp fuse protecting transformer. could be thermostat issues.

No, it is not the brake lamp switch. If the brake lamp switch was not working, the high mount (3rd) brake lamp would also not function.
Chevrolet trucks are notorious for bad tail lamp circuit boards.

Disconnect the electrical connector from the circuit boards. Check for power at the circuit board connector (with the brake pedal depressed) on each side. The brake/turn lamp circuit for the left side is the YELLOW wire. The brake/turn lamp circuit for the right side is the GREEN wire. If there is power at the connector, check the GROUND (BLACK wires) to make sure they are getting a good ground. If the power and ground circuits are OK at the connector, replace the circuit boards.

NOTE: DORMAN makes a kit that includes circuit boards for both sides it is DORMAN Part Number 70001

If there is no power on the YELLOW and GREEN wires at the circuit board connectors, the most likely cause would be a defective turn signal switch.

the green an yellow wire is a ground. Look for an area on the board with a ground symbol . Can you not match the location from the old board???
Either way the black and red are your positive and negative power, while the third is the ground. The wire probably are located in close proximity to each other.
Let me know if this helps
Jer

...try to soldering all the electronic components of the circuit board...sometimes there's a loose soldering of a electronic component...

Between 1993-1996 dometic used a yellow epoxy filled circuit board that went bad pretty quickly if you have the yellow filled circuit board rather than the green one it is most likely the circuit board

The center circuit board is the green CRT drive circuit. that board could be bad or the green CRT could be faulty. I have access to both those parts for your model