I know that this is a late posting, but some explanation is required.
The red blinking in general is an indication of “protect” mode. This is a case where a problem has been detected and the unit shuts down to prevent further damage to either the receiver or the speakers. As indicated in the posting above, this can happen for a several reasons.
1) Heat - When the receiver works too hard and generated too much heat, it will shutdown the speakers until the temp reduces to a safe level. Once cooled, the receiver will function again as expected. Excessive volume for an extended period of time can trigger this. This is what was reported in the original question.
2) Failure of the Amp section - In this case, the unit will show the protection stage immediately upon turning on. This is the shorter interval flashing. In most cases, the output transistors have failed (at least one). When this happens there is DC voltage present on the speaker line which will cause the speaker voice coil to heat up like a light bulb. This is not good for the speaker and will cause it to fail. To prevent this, the Amp will detect this DC voltage and shutdown the output.
3) The speakers have failed creating short circuit on the outputs - In this case either the speaker wires have crossed or the speakers have failed. Since the Amp is expecting a particular “load” for the speakers, a short circuit will create too much of a load and the Amp will work too hard drawing too much current. This too is detected and will cause a shutdown.
These are the main causes of protect mode.
Hope this helps,
Dan