[Motorola] spectra fail code 08/10 option serial bus failure

[d.stiver at att.net]

I am trying to use a Spectra I purchased on ebay model # T84FWA7HA9AK I was able to enter all my freqs 440-470 with out any problem. Radio has intermitent xmit and intermitent receive. Manual says Option serial bus failure see Spectra 9000 Siren/Pa option manual. I do not have this manual. I went into program of radio and turned off siren option and in the control head. Also tried diff head that wks on another Spectra. Same fail code. HELP Thank you Don K7LHR