Marantz SR5600 receiver troubleshooting.

Check the main filter capacitor at its power supply section circuit. Electro help

You need to go to Menu/Input Setup/Input Assign. In the column labeled COMP, assign the Component Inputs (1-RCA through 4-RCA) to the various Sources.

You may need to go to each Source and turn Video Convert to On. Select an Input, such as SAT. Go to Menu/Input Setup/Video/Video Convert and select On.

www.manualowl.com/p/marantz/sr5600/manual/121048

are all the speakers connected 1.5s
all the same watts helps
is that one with an inbuilt amp ?

what a mess or connectors at the back of one of these

Model SR5500 User Guide - Marantz

us.marantz.com/DocumentMaster/US/DFU_SR5500_Final_Eng.pdf

It is possible that the amplifier had encountered a fault with a higher current drain which had triggered it to a protection fault condition. The fault can be your output drivers- the MOSFETS/IC's fitted for both the channels, Use a meter after disconnecting to check for short in the drivers. Disconnect the positive and negative voltages to the output and see if the protect changes. Even a fault in the preamp stages that drives in high current into the output can shut the Amplifier. Sometimes this can be a noise like a HUM or HISS before the protect works. Faulty capacitors in these circuits also can cause similar issues and needs close observation.
You need to confirm and replace the specific stages or outputs. If not there can be issues in the mother board, maybe the protect circuit by itself is shutting off due to a faulty bias , maybe a leak in any voltage/current sensing circuit. Also disconnect the speakers and test, if the protect is off then check for short on the speakers.

The Amplifier was failing and that's why you were getting the crackling noise.

Most receivers have an Auto Protect that shuts the system down and goes into Protect mode at the first signs of failure or overheating, usually indication by 'Protect' on the display.

I'm presuming from your post that you never got any indication that the unit was shutting down to protect itself and has just failed, so I'm presuming that this facility isn't fitted on this model.

Depending on you Technical ability it could be an easy repair (replacing the complete PCB or some PCB components). Your only other solution is a visit to a service engineer.

It sounds like you're guessing.

Register and download the manual for free at retrevo.com

http://www.retrevo.com/support/Marantz-SR5600-Receivers-manual/id/511dj787/t/2/

Also check in with the DVD manual.

Check all your speaker wires carefully. Chances are good that a braid has crossed from + to - and causes the unit to protect itself. This is a very common problem! everyone's done it at some point. Check connections at both the receiver side and the speaker side. If you still have a problem, post a comment and I can help you troubleshoot further. Hope this helps.

I think it may be related to set up of crossover frequencies within 'menu'. There's a menu where speaker sizes are set, as far as I remember the lowest setting suggested crossower freq for sub somewhere at 80hz as default which may be too high of you have sub.