Powering-up Apple 1 Replica for First Time

Hi Everyone,  I've recieved lots of help over the last 3 months from people on this forum while I collected the components and built my first Apple 1.  I've followed Mike Willegal's "Apple 1 Mimeo Computer Assembly and Bring Up Guide", and am now at the point if testing the Video Circuit.  I 'm based in Australia so shipping here can be expensive and slow.  After power up, I see characters scholling up, the the screen is blank becides the 20 x 24 dot matrix (I've read Mike's Hardware notes how to eliminate these, page 4/6).   I beleive I have made a Rookie mistake and purchased 74LS161AN ICs for D-7-D9, D11 and D15. I see now that D8 needs to be 74161, not 74161AN. I have ordered 10 SN74161 from Sydney. I have checked the board, as much as my sanity allows.  When I short D6 Pin 1 to CLA, I get a screen full of ASCII charcters. Afterwhich the screen can be cleared, back to the 20 x 24 dot matrix. If anyone can help, that would be great.