DVD/TV Problem with TX-LR552

I did find your Service Manual

https://www.manualslib.com/manual/1150671/Onkyo-Dv-Cp702.html

Lots of help here on Fixya from 2008 with the reasons.

https://www.fixya.com/support/t474556-onkyo_dv_cp702_will_not_load_any_disks

Nothing on Service Bulletins

https://www.google.com/search?q=onkyo+dv-cp702+service+bulletin

..

Hello Chris, did you test if the remote cotroles emit?
to test take the cell phone, put it in camera mode and point the transmitter of the remote control at the camera and press the buttons, every time you press you should see a light on the transmitter of the remote control, if you do not see it, the remote control, it does not work
There would be another test to perform, only if you have an Onkio Receiver, with control output on the back panel, if you have it, you have to place a 3.5 mm Miniplug cable to the 3.5 mm Miniplug, from the DVD player to the the Receiver, this can be seen on page 19 of the user manual of your Onkyo DV-CP702 DVD, with this connection you use the remote control of the Receiver to control the DVD
I hope you can solve the problem
Greetings Franco Dosil

Hola Chris, probo si los cotroles remotos emiten?
para probar tome el celular, pongalo en modo camara y apunte el emisor del control remoto a la camara y presione los botones, cada vez que presione tendria que ver una luz en el emisor del control remoto, si no la ve, el control remoto, no funciona
Habria otra prueba para realizar, solamente si usted tiene un Receiver Onkio, con salida de control en el panel posterior, si lo tiene, tiene que colocar un cable Miniplug 3,5 mm a Miniplug 3,5 mm, desde el reproductor de DVD hasta el Receiver, esto lo puede ver en la pagina 19 del manual de usuario de su Onkyo DV-CP702 DVD, con esta conexion usa el control remoto del Receiver para controlar el DVD
Espero que pueda solucionar el problema
Saludos Franco Dosil

https://www.intl.onkyo.com/downloads/manuals/pdf/dv-cp702_manual_e.pdf

You can get a substitute remote (the original remote is no longer available) at
http://www.remotes.com/remotes/servlet/rs?a=gmi&uuid=13118717212490&smodel=DVCP702&brand_pn=ONKYO_DVCP702
Let me know if you have any other problems or questions.Please rate this solution. Thanks.

http://www.fixya.com/support/t4093524-onkyo_dvd_changer_display_reads_mecha

http://www.fixya.com/support/t1119443-onkyo_dv0_cp702_error_mecha_err

These may help you.

Are you routing the video into your reciver from the dvd player? If so route the video directly into your tv. It won't fix the initial problem but you will get picture and sound to watch dvd movies.

Replace - you can't fix for less than $100.
New are under $50

Could be a couple things.
1. The system has a safety feature that cuts out when to much voltage runs through input/outputs
2. The audio ouputs have fried and will need all new capacitors installed.

What is the model number of your DVD player?

Most of the time its the amps that are bad and need changing. This will be transistors on heatsink in the reciever. Part number should be on the amp.

Hi, If you feel comfortable opening the unit, then you may remove the top cover normally held by 2 - 4 screws. The tray should be visible and most units have a locking bar right at the center to hold the discs down. Removing this (2 screws normally, 1 at each end of the bar) would expose fully the tray with the 2 discs on top. Remove the discs and put the locking bar back with the screws. You can test the unit without the top cover. Please be reminded about safety precaution when working with active/live units and laser equipment. Power it up and check if the "mech err" still shows. If not you're set to cover it up, otherwise, your probably better off seeking the services of a qualified technician. This is a generic method which normally should apply to most CD/DVD units. Good luck and kind regards.