Ecleree PAM2600, Service Manual

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17
STANDBY MONOSTABLE
The only thing left is the function of the monostable made of IC310 (4538).
Like the counter and the monostable IC311 (4538), this circuit is connected to the PROTECT SIGNAL,
too. Its output is "1" in rest state and becomes "0" during an approximate time of 1.3 seconds, which is given by
the constant RC of the circuit R341 C316.
This leads to two situations: First, putting a "0" in one of the legs of the NAND (IC308) generates the
immediate opening the relay, as we have seen before. On the other hand the voltage divider of the DC OUT
circuit is put off balance. The monostable time is calculated to be long enough to unload the capacities of C312
and C313. This way we get a DC OUT circuit initialization as we had done a manual reset (disconnection from
mains), causing the tipical turn-on STANDBY time for each of the disconnections of the relays because of the
protections shooting. Let's take into account that the system is locked after the fifth disconnection.