Power led is blinking fast if switched on

A Marantz UD5007 blinking a red light and then switching itself off may signal a fault or error. It could be due to overheating, disc reading issues, or technical malfunctions. Refer to the user manual for troubleshooting or contact Marantz customer support for help.

sounds like it is overheating but I know of no fix as i have never seen one

Hey Ronald, Try reseating the LED Bulbs. Depending of the bulbs a polarity change might cause them to flicker faster.
The original bulbs were working off a flasher or relay already. Put Hazard signals On see if the same thing happens. Or simply get the original bulbs back in.
You can also try calling the manufacturer of the LED light bulbs with the model number.Let me know what happens.
Good Luck,
JP
PS I have added a link that may help you. https://www.superbrightleds.com/blog/led-turn-signals-blinking-too-fast-hyperflashing/275

This will be a setting issue possibly the signal level for aux 1. Or the level on the phone itself.

If the red led is blinking fast (8x/second) the power supply is likely damaged and the unit will need to be serviced. If blinking slow, the most likely cause would be a shorted speaker connection. To help find the cause, unplug everything including the power and speakers. Connect only the power and try to turn the unit on. If the light doesn't blink, you know you have a shorted connection. Power off and connect the inputs and then power back on. If the light is not blinking, you know the problem is with an output connection. Just find the bad connection by process of elimination.

Manual: http://us.marantz.com/DocumentMaster/US/SR6004-5004_U_EN.pdf

These blinks [flashes] are fault indication (Error Codes). From the number of blinks occur at one time switch ON, you can get an idea about the faulty circuit stage inside it. This will make repair easy. These are called blinking codes. Make sure about the exact number of blinking of the standby/power led, by switching On & OFF the set, for at least two times. Count it carefully. If you wish to get some details, check the site linked here. It has details about blinking codes, and fault locating, to many popular brand TVs and other devices. Viewing it in "Mosaic" will make surf easy.
http://electronicshelponline.blogspot.com/
Blinking codes details to many popular brand TVs are given.

my sound on my marantz av surround receiver sr5003 stopped working, i need help to restore it:

to turn on , press and hold down surround mode,exit and clear buttons for more then 3 seconds,system should reset. if it goes back to a flashing power light you will have shorted output transistors inside your receiver.

Switch off the unit. Then hold down Sorround, Exit, Memory & Clear buttons all together and then switch on the power. This should work.