D-shell connector age?

jpero at sympatico.ca jpero at sympatico.ca
Thu Jan 4 14:36:57 CST 2007

> It;s is a lot easier to isolate a VHF or UHF signal (a couple of special 
> capacitors will do it) than baseband video/audio (which would involve 
> spectial transformers or opto-isolators at least). I've seen a few 
> top-end (B&) and the like) valved TVs (live chassis, of ocurse) which had 
> a special audio transformer to provide an isolated (from the mains) audio 
> output from the set to feed into a tape recorder or whatever. But it 
> wasn't common at all.
> -tony

Very common here also (chassis live) till mid 1990's then changed to 
isolation via the flyback transformer, partial hot chassis till 
flyback transformer.  Then SMPS for isolation.  Some do double 
isolation via SMPS then flyback transformer.

Still, certain area of chassis (just a one board now) even on SMPS is 

Isolation transformer is a MUST when servicing any even brand new 
set.  No buts or ifs.

Cheers, Wizard 

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