![]() ![]() Then, hopefully, the PWR signal would be able to control the 12V and 24V supplies like it's supposed to, and whatever the heck ACD is would just work like it's supposed to. This would then turn on the 12V and 24v supplies, which you'd hot-wire to the 12V and 24V circuits on this board. So you could use any transistor and relay circuit or solid state relay circuit that's capable of turning on the battery to the 12V and 24V converters from a +5V logic signal. My best guess (this is too hard to see in the circuit to be 100% sure) is that PWR is pulled to 5V by the TV in order turn on the 24V and 12V rails. You could figure out which polarity the PWR signal from the rest of the TV is, and use it to drive a transistor which drives a relay or to drive a solid state relay. You could apply 5V to the board's 5V rail. However I have a feeling that things might get weird when the TV is trying to be OFF if the 24V and 12V don't go away.Īlso, it may be possible to actually use the power circuitry to do what it's supposed to do in terms of generating the ACD signal. You might be able to hot-wire it to the appropriate state (either connected to ground or connected to 5V with a ~100k pullup resistor) to get the TV to behave itself. Ultimately I think the best option would be to observe ACD while the power supply is in its various operational states (plugged in/off, plugged in/running). It may just detect the 5V supply is functioning correctly. It sounds like "AC Detect" but it definitely doesn't directly detect the AC line input. So it's possible that ACD is an indicator that power is good. I think U202 is performing some sort of power monitoring function in addition to regulation of the 5V rail. It's interesting to note that while all the application circuits in the STR-A6061H datasheet show a simple TL431 style secondary regulator, the actual circuit uses U202 which seems substantially more complicated. The only trace from 24V runs to R216 and then U201 (which is the TL431 style secondary side voltage reference for the main supply, and sends the regulation signal back via PC101). It doesn't have any traces running to 24V. So it's not a signal that comes from the AC side via an optocoupler. Process of elimination: optocouplers PC101/102 and PC501/502 are all pointed in the direction to carry signals from the output side to the AC side. What's U202 doing? It's telling the rest of the TV something about the power supply, but what? You could confirm this, or take a better picture of that area. ![]() It could be an input, but it sure looks like that trace goes to the collector of Q202, not the base. This means that ACD is probably a 5V logic level digital output of the power supply. Then, a trace runs to what looks like the collector of Q202, and a trace that's probably from the base of Q202 runs via J207 to R240 and then to U202. What is ACD? It first has a pull-up resistor to the 5V rail. ![]() So max power you could possibly need on the 5V output rail is 4A, and I'm sure it's actually delivering far less than that.Īll pretty clear. This second supply only provides a single rail: the 5V rail.Īctually here's the datasheet (STR-A6061H), says 23.5W in open frame mode (which this basically is). This is a flyback supply, capable of a much lower power level, probably only 10-20W max judging by the type of output rectifier (D203) and the size of the snubber resistor (R521). Then, there is a second supply using the other transformer (can't see designator, guessing T501?) driven by U501 (integrated switch controller, so no external transistors). Note that both 24V and 24Vavd (or whatever that says) are driven by this supply, they're really the same rail but the 24Vavd is filtered by an extra inductor and capacitor. I'm going to guess that this supply is turned on and off when the TV powers up/down. This supply is controlled by U101 and driven by transistors Q101 and Q102. These types of supplies are capable of pretty high power levels. ![]() There's a higher power quasi-resonant half-bridge forward converter supply that uses T101/C103 to generate both the 24V and 12V rails. There are two completely separate (or almost separate) power supplies on here. PWR sounds like the power command which is used to turn the main power supply section on and off. I agree with you that DIM and Inv appear to pass right through the board without any functional components, so those should be easy to deal with. ![]()
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