Canon A-1 not talking to the flash/ 199A

My New used Canon A-1 will not show the flash signal in the view finder (F )
When I put my Canon 199A flash on the hot shoe in auto mode.
The flash will fire and the contacts are clean.And the flash works well on My AE-1 P
any ideas ?
Thanks

Try this page.

http://www.mir.com.my/rb/photography/companies/canon/fdresources/SLRs/a1/html/flash.htm