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Old 16th Aug 2019, 5:27 pm   #1
ben
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Join Date: Aug 2006
Location: Madrid, Spain / Wirral, UK
Posts: 7,484
Default SONY SL-HF100 patterning

Recently came across some Beta tapes to check, so fired up one of my Hf 100s which had seen little if any use over the previous couple of years. I noticed that on all tapes there is a moving hum bar-type pattern. Two thin lines of 'static' scroll gently up the picture. Also happens in pause. This is overlaid on the otherwise perfect image and does not produce any tearing or instability.

Last year I had a C30 with a similar fault, some criss-cross /herringbone patterning and that ended up being down to a 22uF cap in the PSU. However, the (SMPS) PSU in the HF100 is more complex. There is a panasonic-style metal can which gets pretty warm in operation, also a daughter board in there which makes it quite cramped.

My HF100 service manual, which I downloaded, does not seem to have the PSU diagram in it. I could just shotgun all the caps but I would prefer to at least try and narrow this down. Presumably the secondaries (9v, 12v lines) would be the most likely area. Here's hoping someone recognizes the problem!
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Ben.
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