Hello All,
I am trying to repair my defective OnkyoTX-NR414, which won't switch on. Pressing the On button doesn't do anything at all, device stays dead.
I didn't do any voltage measurements with the receiver connected to the mains yet, just started with resistance and diode tests using the service manual as reference.
I already found a few suspects. The PSU pcb contains 2 Sharp PC123 optocouplers, that appear to be malfunctioning. Measuring out of circuit with my Metex 3650 on diodetest, on both optocouplers the fototransistor shows 'open' in either direction. I expected at least one direction should show around 0.6V, just like a diode. Is the PC123 something special, that its fototransistor can't be tested this way?
Of course it's possible both optocouplers failed at the same time, but wouldn't that be too much of a coincidence? On both optocouplers the IR-diode measures OK, btw. If they both are defective, what could have caused it?
Besides that, relay 9001 (TYCO SDT-S-109LMR2) seems to fail. When measuring its coil in circuit on diodetest, one direction shows 'open' and the reverse direction around 0.6V. This voltage will probably be due to the 1N4148 connected to the coil. I will desolder the relay later on and repeat my measurements.
Has anybody already repaired an Onkyo TX-NR series with similar symptoms? The HDMI board has already been replaced (because of designflawed TI HDMI chip), so I would like to get this receiver working again.
I already read this thread:
https://www.badcaps.net/forum/showthread.php?t=63434
Transformer T9001 in my PSU is OK. I'll check the relay's impedance after desoldering and report my findings.
re-atari
I am trying to repair my defective OnkyoTX-NR414, which won't switch on. Pressing the On button doesn't do anything at all, device stays dead.
I didn't do any voltage measurements with the receiver connected to the mains yet, just started with resistance and diode tests using the service manual as reference.
I already found a few suspects. The PSU pcb contains 2 Sharp PC123 optocouplers, that appear to be malfunctioning. Measuring out of circuit with my Metex 3650 on diodetest, on both optocouplers the fototransistor shows 'open' in either direction. I expected at least one direction should show around 0.6V, just like a diode. Is the PC123 something special, that its fototransistor can't be tested this way?
Of course it's possible both optocouplers failed at the same time, but wouldn't that be too much of a coincidence? On both optocouplers the IR-diode measures OK, btw. If they both are defective, what could have caused it?
Besides that, relay 9001 (TYCO SDT-S-109LMR2) seems to fail. When measuring its coil in circuit on diodetest, one direction shows 'open' and the reverse direction around 0.6V. This voltage will probably be due to the 1N4148 connected to the coil. I will desolder the relay later on and repeat my measurements.
Has anybody already repaired an Onkyo TX-NR series with similar symptoms? The HDMI board has already been replaced (because of designflawed TI HDMI chip), so I would like to get this receiver working again.
I already read this thread:
https://www.badcaps.net/forum/showthread.php?t=63434
Transformer T9001 in my PSU is OK. I'll check the relay's impedance after desoldering and report my findings.
re-atari
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