Ampex 354, Tape curling up under glass rod guide when exiting reproduce head

[Lairbear]

Hi,

My 354 records/play just fine, but I noticed the tape, when passing past the reproduce head, rides/arcs up under the top glass rod guide while moving to the puck. I don't care for the glass rod scheme...the machined guides of the later period are more stable.
I'm thinking about using the newer machined guides, but that will ruin the originality of the unit.
What could be causing this issue, it's bugging me...I don't want missed audio output from reproduce head.
So far, I'm still lucky.
I hope it's not a worn head.

Lairbear

 

[radardoug]

That would indicate to me that the pinch roller is not parallel with the capstan, either due to roller wear or mechanical alignment.
It is pulling the tape up. There is nothing wrong with the glass guides, or the ruby guides that followed them. They will wear slower than metal guides. Try turning the pinch wheel over and see if the tape pulls down. That would indicate pinch roller out of square.
If the fault continues, it indicates capstan or pinch wheel shaft not square with the deck plate.

 

[gar381]

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GARY