Sony RM-ASP001 for 400 disk changer stopped working
Try the command code switch. I recently had a similar problem when my remote suddenly stopped working. It worked fine one time but nothing the next time I tried it.
I checked the emitter with a digital camera and found it was not working. I did the remote reset (remove batteries and push all the buttons twice, reinsert batteries) and the emitter was now working. However, the remote would still not control the base unit. I did the remote base code reset (push power, volume and TV/DVD buttons together) but this did not help. I then checked the command code switch. This is a small three position slide switch located in the battery compartment on the remote. I slid the switch back and forth several times returning to the default number one setting where it was before. I did not change anything on the base unit but the remote now worked.
Hope this helps.
on Nov 09, 2015