Classic 150 won't charge

Could you post  picture off  the display.

Copied from the link below, which was copied from else where...;

To find the "LAST Reason For Resting"

From the main status screen hold the left arrow and tap Enter. The top middle number is the "Last" RFR

Remember this is over written the next time it goes to resting

This table was stolen from a post by boB - hope to make it easier to find:

                      Reason  For Resting:

   ...  "

    ReasonForResting = 1    Wake state, (Vpv < PreVoc AntiClickSenstvty  (MB Addr. 4236)
    ReasonForResting = 2    Insane Ibatt on WakeUp state (offset changed from off state)
    ReasonForResting = 3    Negative current on WakeUp state
    ReasonForResting = 4    dispavgVpv < (dispavgVbatt - 10) Now -25 (RestartTimerms = 1500)
    ReasonForResting = 5    Too low power and Vbatt below set point for 90 seconds
    ReasonForResting = 6    FETtemperature >= 100C Hot
    ReasonForResting = 7    Ground Fault
    ReasonForResting = 8    Arc Fault
    ReasonForResting = 9    (IbattDisplaySi < -15) (negative current) (MB 4200)
    ReasonForResting = 10   (dispavgVbatt < LBDlowV)  Battery less than 8 Volts
    ReasonForResting = 11   Vpv >= 90% of Voc but slow. Low Light #1
    ReasonForResting = 12   Vpv < 90% of Voc   Low Light #2
    ReasonForResting = 13   Vpv > (Voc + 10V) in    PV_Uset || Solar1_OandP
    ReasonForResting = 14   Vpv >= 90% of Voc  but slow.  Low Light #3
    ReasonForResting = 15   Vpv < 90% of Voc and taking too long.  Low Light #4
    ReasonForResting = 16   Normally because user turned MODE OFF...  Disabled
    ReasonForResting = 17   Vpv > 150V  (classic 150)
    ReasonForResting = 18   Vpv > 200V  (classic 200)
    ReasonForResting = 19   Vpv > 250V  (classic 250)

    ReasonForResting = 22   Average Battery Voltage is too high above set point  (RestartTimerms = 2 sec)

    ReasonForResting = 25   Battery breaker tripped  (Vbatt shot up high)
                            (If RFR = 25 on Wakeup, check modbus register 4200)

    ReasonForResting = 26   Mode changed while running, Vabsorb raised more than
                             10.0 Volts or Nominal Vbatt changed by modbus command
                             AND MpptMode was ON when changed...

    ReasonForResting = 27   bridge center == 1023  (R132 might have been stuffed old units)
    ReasonForResting = 28   NOT Resting but RELAY is not engaged for some reason
    ReasonForResting = 29   ON/OFF stays off because WIND GRAPH is insane
    ReasonForResting = 30   PkAmpsOverLimit (will change somewhat 1-23-2013)
    ReasonForResting = 31   AD1CH.IbattMinus > 900   (peak negative battery current)

    ReasonForResting = 32   Aux 2 Logic input is high.  Aux2Function 15 (external disable/enable)
    ReasonForResting = 33   OCP in a mode other than Solar or PV-Uset (1-10-2013)
    ReasonForResting = 34   AD1CH.IbattMinus > 900 Classic 150,200 newer than 1-23-2013
    ReasonForResting = 35   Vbatt < 8.6 V  (LOW LOW battery)
    ReasonForResting = 36   Battery temperature is Greater than reg address 4161 specified
    ReasonForResting = 38, is the new sleep because "other charging sources appear to be active"
    ReasonForResting = 136  Battery temperature fell below MB reg. 4161 - 10 C (Classic turned back on)


    ReasonForResting greater than 100...  100 + PowerOnReset, WDT, etc...
    ReasonForResting = 104  Watchdog WDT reset (only at boot until first RFR)
    ReasonForResting = 111  Normal Power up boot (only at boot until first RFR)

                 [ 100 +   1 = POR,  2 = Ext. Reset  4 = WDT  8 = Brown Out ]

http://midniteftp.com/forum/index.php?topic=2034.0

Did you check what code the Classic is giving you?

Usually when you see zero volts at the input only when the PV array is connected to the input it means one of two things....

Either the polarity of the PV is backwards, but your system has been working so that cannot be it.

OR, the Classic is broken.  Shorted input.  Bad FETs.   Usually when you disconnect the PV from the PV input, you would see some arcing if the sun is out.

Call MidNite Solar technical service.   360-403-7207