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-   -   SONY SL-HF100 patterning (https://www.vintage-radio.net/forum/showthread.php?t=158956)

ben 16th Aug 2019 5:27 pm

SONY SL-HF100 patterning
 
2 Attachment(s)
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!

collisr 18th Aug 2019 12:21 pm

Re: SONY SL-HF100 patterning
 
1 Attachment(s)
Hi Ben,

Haven't seen your problem but here is the PSU diagram from my service manual. PM me if the resolution isn't good enough

davyrocket2 18th Aug 2019 8:39 pm

Re: SONY SL-HF100 patterning
 
Hello Ben.

I suggest two solutions. Try the Betamax palsite, Noel Higgins he is very good on Betamax and based in Australia, or Kevin Lambert also on this forum Sanbeta.

I have a similar problem on a C9 but am concentrating more on getting a Sony 950 sorted which needs hall sensors.

ben 20th Aug 2019 11:41 am

Re: SONY SL-HF100 patterning
 
Thanks for the pointers. Will take a closer look when I get back. It also ocurred to me that I should try it on another TV in case there is some peripheral which is leaking hash onto the chassis returns, that has caught me before. Will update.

Sanbeta 26th Aug 2019 7:15 pm

Re: SONY SL-HF100 patterning
 
Ben

Check all grounding areas, especially near the head amp and head drum shielding bracket and also all caps in the PSU ,Especially the smaller sized ones. This model and the C9 usually have the biggest amount that are going high ESR if it's been on for long periods of time.
The C20,30,40 don't suffer half as bad and usually only one ,that causes herring bone type diagonal patterning, as you have found.
Have seen a similar effect on a Sanyo M20 that eventually went away.
Also keep ALL modern technology OFF the top and well away from these vcr's They can and do cause picture effects to some models of TV, especially plasma and some lcd's.

.Kev


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