I’m in need of assistance with a Rotel RSX-1055 receiver. The unit powers on but appears to be stuck in stand-by. The display does not turn on. From what I’ve researched, it could be stuck in protection mode.
I have verified all fuses are intact (resistance checked), I’ve pulled the amp board and tested all output transistors and drivers (none are shorted or giving values that are way off). I’ve pulled and tested all Q215’s of the protection circuit and Q217 and they all seem ok. The power supply is outputting 50V.
Any ideas on where to go from here?
Thanks!
I have verified all fuses are intact (resistance checked), I’ve pulled the amp board and tested all output transistors and drivers (none are shorted or giving values that are way off). I’ve pulled and tested all Q215’s of the protection circuit and Q217 and they all seem ok. The power supply is outputting 50V.
Any ideas on where to go from here?
Thanks!
A blank display is suspect. Make sure you check all the +5V regs on the main board (NJM7805FA, no less than 3), NJR parts have not always been the most reliable.
Thanks Sgrossklass for pointing that out, looking into that issue it does seem like it certainly could have something to do with it. When i get a chance I will measure all the voltage regulators on the main board. I'll post my findings....
Thank you
Thank you
As an update on this, here is where I am at.
I checked all the voltage regulators I could access (all except the two 6v regs). Out of the five I was able to check (three 5V, two 15V) Only one 5V (IC901) was actually outputting 5V. All the others were less than 2V and the 15V were not showing anything at all.
Following upstream, measuring the output of the rectifiers, I think I may have some bad diodes or other issues. The rectifier that supplies the 15V regs is outputting 0.5V but that voltage starts at about 3V when you first turn on the unit and falls over the course of a minute or so to that level.
The rectifiers that supply the 6V and 5V regs are outputting between 1.2V and 1.6V.
The 5V regulator that was working ok does have it's own rectifier and the AC source is the standby board.
Is it possible that three rectifiers with two separate AC sources (two different taps on the same main transformer) would be bad? Could the transformer be the source of the problems?
I'll start with doing a check of the individual diodes and go from there.
I checked all the voltage regulators I could access (all except the two 6v regs). Out of the five I was able to check (three 5V, two 15V) Only one 5V (IC901) was actually outputting 5V. All the others were less than 2V and the 15V were not showing anything at all.
Following upstream, measuring the output of the rectifiers, I think I may have some bad diodes or other issues. The rectifier that supplies the 15V regs is outputting 0.5V but that voltage starts at about 3V when you first turn on the unit and falls over the course of a minute or so to that level.
The rectifiers that supply the 6V and 5V regs are outputting between 1.2V and 1.6V.
The 5V regulator that was working ok does have it's own rectifier and the AC source is the standby board.
Is it possible that three rectifiers with two separate AC sources (two different taps on the same main transformer) would be bad? Could the transformer be the source of the problems?
I'll start with doing a check of the individual diodes and go from there.
From the description of the problem and the procedure seems that you will not manage it seek for expert help .
Ok, making some progress here. I replaced 10 of the rectifier diodes that feed the 5v and 6v regulators. Now where I was getting only 1.5v at the diodes I'm getting 9.5v or so.
So I got it to turn on, but here's the problem, without the amp module. I confirmed by having the amp module totally hooked up it stays in protection, when I unplug CP908 on the main board it does turn on. As I mentioned above, I pulled and tested all outputs and drivers, as well as the Q215s and Q217 and nothing red flagged. There must be something else happening.
So I got it to turn on, but here's the problem, without the amp module. I confirmed by having the amp module totally hooked up it stays in protection, when I unplug CP908 on the main board it does turn on. As I mentioned above, I pulled and tested all outputs and drivers, as well as the Q215s and Q217 and nothing red flagged. There must be something else happening.
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