Ampex mm1100 capstan circuit board

[miles newbold]

Hello, I have an Ampex MM1100,and we are having a problem with identifying whether the intergrated circuit that has the Schmitt trigger on for the capstan is an A.C.T or a H.C.T? The original writing on it is barely readable......any info would be great,Thanks.Miles.

 

[soundguruman]

Get all the schematics and service manual FIRST.
http://www.recordist.com/ampex/docs/parts/ampexpts.html