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« on: May 28, 2011, 09:28:34 AM »
Thanks, Chris, I appreciate the helpful suggestions. I do have an MRL 1510 tape and Jack indicates, in his A77 service manual, that playing a 250nW/m reference should produce 1.6v with the A77 playback level all the way clockwise. If the tape is played on the A77 and then the ST would be set with this as the input reference level. Then set the ST output levels to 1.6v and adjust the A77 record levels for "0" VU. This is assuming that if the A77 had VU operation during playback the test tape would produce "0" VU.
In fact I had an interesting thing happen with the alignment tape. I was testing the azimuth with the ST on an A77 that I had done a very thorough overhaul, all the way back to the supporting frame, cleaning everything possible. I kept getting "0" for all four of the azimuth test frequencies, no vertical bars. I thought the ST was bad, maybe the tape wasn't made correctly (very low probability of that) or (most likely) I wasn't doing the test correctly. I then setup an older A77 that is stock and found 4% phase error at the first testing frequency, smaller errors for the remaining frequencies. Put my rebuilt back on the ST and perfect response, no phase errors between the two channels.
Thanks for suggesting Jack Clark, he's been helping me for a long time with A77 and PR99 parts and tips.
Cheers, Ken