Bad circuit board?

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  #1  
Old 05-31-18, 04:17 AM
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Bad circuit board?

Bryant two-speed air conditioner with Puron refrigerant model 598BNX048000 installed in 2004. Lightning hit right next to the house today. Ecobee thermostat rebooted. Fan runs fine, but the A/C hasn't worked since.

I tried turning off both circuit breakers, waiting a while, and turning them back on, with no luck. Inside the condenser I'm getting 245v to both contactors, 26.6v constantly on R, on Y1 when the Ecobee signals stage 1, and both Y1 and Y2 for stage 2. The contactors are not getting voltage on the coils. The status LED on the board is flashing constantly with no pause, which apparently means "No demand/Stand by". The flash codes on this board are fairly comprehensive (included below) and it is not indicating a board failure, but it does not appear to be seeing the signals from the thermostat.

Does this sound like a board failure to you too, or am I missing something? These boards are not cheap. Had any luck repairing them?

Is there a way to bypass this board so I can confirm the rest of the unit works? I'd hate to replace this board only to find that the compressor is toast too. I was considering connecting Y1 directly to the LO contactor coil. Does stage two energize both coils or just the HI one?

This board does have ABCD connectors. I'm thinking maybe the Y1/Y2 connectors fried, but ABCD may still work. Is there a way to test this? Are there inexpensive thermostats that can connect to ABCD?

The board I think is causing the problem: https://www.repairclinic.com/PartDetail/2381071
Bryant 598B Installation And Start-up Instructions Manual: https://www.manualslib.com/manual/45...yant-598b.html
Bryant PURON PLUS 598B User Manual: https://www.manualslib.com/manual/22...Plus-598b.html

LED FUNCTION LIGHT CODES
A constant flash with no pause indicates the unit is in the
standby mode. That is, the thermostat is satisfied and the unit
is ready to respond to call for heating or cooling.
One flash with a pause between indicates the unit is in low
speed mode.
Two flashes with a pause between indicates the unit is in high
speed mode.
Three flashes with a pause between indicates a failure of the
outdoor air temperature thermistor.
Four flashes with a pause between indicates a failure of the
outdoor coil thermistor.
Three/Four flashes with a pause between indicates that the
thermistors are out of range.
Five flashes, a momentary pause, plus one additional flash with
a pause between indicates the low pressure switch is open. Five
flashes, a momentary pause, plus two additional flashes with a
pause between indicates the high pressure switch is open.
Six flashes with a pause between indicates the VC/VH has shut
the compressor down.
If the light is on constantly with no flashes or no pauses, it
indicates the board has failed and must be replaced.
 
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  #2  
Old 05-31-18, 04:56 AM
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Looking at the board closer I can see the traces from Y1 and Y2 going into two surface mount resistors. When the Ecobee is asking for stage 2, I can get 26.6v on the left side of each resistor, but nothing on the right. I think this means the lightning probably fried them.
 
  #3  
Old 05-31-18, 07:41 PM
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That board processes data. If lightning struck nearby it's more than likely zapped.

ABCD are data connections to the stat. That stat will not be inexpensive.
Check those two resistors with an ohmmeter. The value is stamped on them.
 
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