Modifying a B&W TV for composite video input

Tony wrote: Yep. Nasty. Even with isolation still can get that ZAP!. Every one you described for non-isolated sets are like this. Every one, I'm referring to cheap color sets old or new. The - side of rectifier bridge is "hot ground" in those. Very rare few I seen had one diode and that was in old citizen sets usually 13" to 19". This is really downright cheap. In those with non-isolated sets that does have inputs, always have small signal isolation transformers and or optical isolation. The others that is both hot/cold chassis be it via flyback transformer like this one hitachi and about 7 yr old. Other kind via SMPS is very common. Using mains isolation transformer is *extremely rare*. In so many sets in 1 and half years of sets (cranks out about 30 sets every 5 days) I worked on, only ONE did by design and that was really ancient Samsung 32" tv. So do your self a favor buy a newer used or new sets and hook up things without modifying that set or be hackish on old stuff, splice it on that internal mains wires a isolation transformer and bolt it inside that set. 13" is considered portable also and almost always are hot chassis by design. In RCA 13" AC/DC tv it's hot chassis, to run on 12V RCA puts in an DC to DC converter! I'm talking about those that is made 13" RCA has no B+ regulator and the pix is very stable because of direct control of horizontal pulses to regulate power in flyback itself. Hence very little horizontal size swelling or jaggies with bright parts. The later 13" RCA tvs gained mono audio and video input after it got the SMPS but basic design of pervious 13" RCA mostly unchanged. By contrast I have seen so many other sets that doesn't have good handle on the HV regulation the pix width swells with bright parts and shrinks with darks. This drives me nuts. Those have same chassis but has pincushion feature added (it is a module in RCA) had better handle on this but not 100%. If the vertical edges isn't straight (more of a flared or jaggies) that what I mean by this poor HV regulation.