How Do you Turn A TV Into A murder Weapon.....

[Alvin]

.....without leaving a trace? According to police surgeon Dr Lucien Blake you could connect the HT supply from the cathode ray to the aerial socket thus zapping anyone who touched the set top aerial but that, he said, would blow the tube - errm why?

I'm talking about BBC1's daytime drama The Doctor Blake Mysteries and yesterday's episode was set in a TV studio where two contestants were murdered, one by the tampered with TV and I won't spoil things by telling you tell you how the second contestant was dispatched.

The episode can be seen here http://www.bbc.co.uk/iplayer/episode..._of_Champions/ - it's a pleasant enough series set in the late 50s and oozing with period charm particularly this story centering around television of that era.

Alvin

[ukcol]

I enjoy watching this series but agree that the science behind this electric shock murder is suspect.

The body had burns on the soles of the feet said to be caused by the electric current from the sets EHT system. Even the early mains derived EHT systems, although lethal, probably couldn't supply enough current to cause that sort of damage. Sets of that period (1950s) had flyback derived EHT and probably would not even have killed him.

[Alvin]

In fairness later in the programme Blake was advised by the tv engineer who called to his house after he'd experimented with the home set that it could have been done by connecting the mains input to the aerial socket.

[Peter.N.]

The current available from flyback EHT is unlikely to kill anybody unless they perhaps have a heart problem, I have had enough shocks from it over the years, mains on the aerial socket though is a different story, some of the worst shocks I have had have been due to faulty aerial socket isolating capacitors and a reversed polarity mains connector, as you usually grab the aerial plug hard to pull it out you are making very good contact with it, in most cases you won't feel a thing unless you happen to be leaning on a radiator or something else earthed, or on a stone floor with wet shoes then it can really hurt

Peter.

[Welsh Anorak]

Hi
I remember one TV repair shop we didn't hold in high esteem 'repaired' a damaged isolated aerial socket on a half-live TV by soldering hald a coax flylead directly onto the tuner and left the lead dangling for connection to the aerial. Worse, this set was used in a child's bedroom - 'Mummy - that metal thing bit me!'. She brought it to us - I explained that it was potentially lethal (no pun intended). When she realised the possible consequences she said she's take it further.
The other shop bad mouthed me for years to come for 'letting the side down'. That sort of side deserves letting down!
Glyn

[Nicklyons2]

There's an episode of Ironside (circa late 1960s) where, trapped in his room alone, Ironside senses a killer is creeping up on him and wires up the tv to the door - the killer arrives - Raymond Burr, remote in hand, greets his would-be assasin, flicks the remote and the killer is zapped. Ah the dramatic licence of it all!

[G6Tanuki]

Remember that US TVs have always tended to use mains-transformers [because they only started off with 117VAC supplies] rather than the European series-connected-heaters-and-half-wave-rectified-240V-mains approach.

A typical valve-era US TV-set will harbour a big beefy transformer with something like a 350-0-350V@300mA HT winding, along with a couple of 6.3V 5a-or-better heater-windings].

[these are still sought-after by 'stateside radio-hams because you can use them to build nice linear-amplifiers using ex-TV "Sweep-tubes" like the 6LF6 or 6KD6: a single 6LF6 has 40 watts anode dissipation and can be pushed to produce 175 Watts of SSB output in what Doug DeMaw described as the "Skinnier Linear" - see QST for April, 1970. Pages 32-35]

Given 350-0-350V at a couple of hundred milliamps, I could quite easily come up with a circuit that would give anyone grabbing the doorhandle a seriously life-shortening electric shock.

[Tim]

ISTR there was an episode of Quincy that featured a boy with special needs killed by touching the innards of a TV his dad was working on.

[AC/HL]

We criticise TV people for showing a 50s radio in a 40s setting, I can't believe we are seriously discussing nonsense plots in fictional wrongdoings

[julie_m]

And anyway, they probably would deliberately alter some of the details, to avoid problems with anybody Trying This At Home. Otherwise, they would be running a "how to get away with murder" guide!

I'd suspect any process they described in any detail would be more dangerous in real life to the would-be murderer than the intended victim, so if anybody did try it at home they would have no-one but themselves to blame.

[Radio Wrangler]

People have been killed by shocks while fixing TV sets, but I don't suppose its a reliable enough method for a planned murder. Just dropping the TV from a great enough height would be better.

Still, it's daft trying to apply logic to the Hollywood universe. All the physical laws are different there.

David

[chip-chop]

I remember a Bush T20 that tried to murder me once many years ago.
I got called out to a fault, I can't remember what was wrong with it but I believe it was working after a fashion when I got there, anyway, I turned it off at the switch, turned it round on the stand and took the back off while squatting down behind it, as I shifted the back out of the way I lost my balance and instinctively grabbed whatever came to hand, in this case it was the chassis of the set with one hand and the metal casing of a fixed gas fire with the other - Zap !!! full mains = that hurt

It turned out that the mains on/off switch had welded itself closed on the live side, rendering the chassis live via half the bridge rectifier, I guess I should have known better really and unplugged it, the remote T20's & 22's were notorious for faulty = stuck on switches, of course they normally only show up when both sides have welded themselves shut and the TV wont turn off.

There you go, at least I lived to tell the tale

[Steve_P]

Get a very old set with Mains EHT. Wire the EHT to the doorknob. Switch TV on, Wait...

Cheers,

Steve P.

[HamishBoxer]

Lets not go down the path of calling Tv,s murder weapons or we will have a crackdown by "Elf and safety"!

[ntscuser]

Originally Posted by ajs_derby

And anyway, they probably would deliberately alter some of the details, to avoid problems with anybody Trying This At Home. Otherwise, they would be running a "how to get away with murder" guide!

I'd suspect any process they described in any detail would be more dangerous in real life to the would-be murderer than the intended victim, so if anybody did try it at home they would have no-one but themselves to blame.

I agree with that. My understanding (which may be wrong) is that TV shows and movies never show the correct way to commit a crime.

[HamishBoxer]

Think we are getting to the point Steve where this thread is going to close.

[Sean Williams]

Agreed, thread now killed off.