Onkyo TX-NR818 Transistor Substitutes for TTA0001 TTC0001

[kingswoods]

Hi guys I am a noob and I have read somewhere that 2SC5200 and 2SA1943 are suitable replacements for the TTA0001/TTC0001 as they are obsolete. Does this sound right and is it ok to just replace one pair of these transistors in my Onkyo TX-NR818? I can see the TTA/TTC on eBay but apparently they are all Chinese fakes.

[m k]

Quick peek indicated yes.

What you think?

[kingswoods]

Thanks MK, yes I think they look suitable but it looks like mine are actually ok and I'm having trouble what is making this thing go into protection mode. All those transistors and the emitter resistors look ok so Im a bit stuck now.

[macboy]

Usually these receivers have multiple fault detection circuits. Usually they have over-current, DC on output. Sometimes temperature, power limit (simultaneous high-ish power on multiple channels). You need to determine which is tripping the protect, then work backwards from there to the fault. Remember that a fault detection circuit may itself be faulty, giving you a false positive fault detection.

[kingswoods]

Thanks Macboy I put it back together to test but left out the preamps but now it doesnt start at all. I saw a youtube where they did this with a different receiver to eliminate the preamps from the diagnosis but it hasnt worked for me. Do you think I screwed up the assembly or it needs them installed to go into standby?