A friend has a older Zenith Z60Z83R Mfg. date May 2007:

1. Who made this for them? I believe this is before Goldstar bought out Zenith. Possible Hitachi?
2. What (if any) is the OEMs' equivalent model number?
3. Is there service menu access, or are the convergence controls, board mounted 'pots'?
4. If there is a onboard 'service menu' what is the access code?

Thanks in advance.