Please post the numbers on the transistors q1 and q2.
bout time we stopped assuming anything.
bout time we stopped assuming anything.
Pin 3 is .304mv engaged, 0mv disengaged
Pin 7 is .3V
C3 is 47/16
The thing is that this 0.3v reading could be a meter artifact, as the circuit drops the relay immediately.
The only way that 0.3v is believable is if the unit continues with the relay PULLED IN.
Realistically 0.6 to 0.7v is needed before any current begins to flow in the transistor collector to emitter.
Not sure if he was looking for voltages or the part numbers marked on the IC body? 2SA733 and 2SC1438 according to the schematics, but who knows if they might have been replaced in the past?
Part Numbers. Those are Original Factory Transistors, go with ksa992 and ksc2690 if you have them.
A lot of my original assumptions have been ruled invalid by this news.
The "minty" status of either 1280 was no where near my standards for a minimal recap, no less a remanufacture, which is what I ASSumed was done.
Plus I swallowed the initial assumptions of the first posts and ran with them UNskeptically.
The six seconds was the delay between power on and the relay pulling in. AFTER which it would immediately drop out for another 6 seconds.
Ok, some basic checks:
(I checked the thread first to see if we already did this, because I was getting a strong sense of deja-vu )
Is C1 (220uf 25v ) new or not?
1. temporarily ground the collector of Q2, to make sure the relay will pull in and STAY in.
2. Q1 gets disconnected, see if relay still cycles, leave disconnected for now.
3. ground pin 4 temporarily, see if cycling stops.
so I WANT AC voltage reading ( probably around 100 volts) of the board's pin 12. Then the PA3004's pin 7.That integrated circuit senses on it's pin 7 the AC voltage through a voltage divider (r10 1.8m, r9 680k, in > out = 27%) monitoring the pin 12 RED transformer wire that is supplying the raw speaker power (+/- 76 to +/- 65 V DC) for the LEFT channel.
it's a bit harder to figure out what makes it unhappy when compared to a transistor implemented protect circuit.
i would think pin 12 is about right .power supply pins 9 and 10 should confirm this . + -76v ...