Hitachi VT-498 detection problems
 

I have an old Hitachi VT-498EM Multi-system VCR which i owned since 1988 and played only about 200hrs on it and it has been stored since 25 years with taking it out for testing time to time....

I have a strange problem which occured that the it doesn't autodetect what TV-system i am running when i put in a PAL or NTSC tape, it seems to lock onto NTSC and if i change it manually it doesn't work, only if i cut the power to the VCR it changes system.

I have the service manual but i don't understand what circuit input what system the tape is recorded with, eg PAL/SECAM/NTSC? is there some sensor that reads the tape?

I don't know how to start troubleshooting it...