easy job turns into a pain

[chris2k2]

hi there, i did a supposedly easy job on a bungalow today which turned out to be a real pain.....

customer wanted new aerial on gable end running to 4 tv points using existing cables as the customer refused blatantly to have new cable runs.....

no problem or so i thought aerial on pole on gable end....into loft...2 way variable masthead then 2 x 2 way splitters running to the 4 points....

connected all up as above....i thought mmm nice n neat job......started prepaing the cable for the power supply for the masthead....

plugged everything up turned the main tv on and noticed no picture....

i thought eh.....wats gone on here....so i disconnected the aerial feed coming from the wall and the psu lit up.....

so i thought short on one of the connectors or a face plate with dc decoupling cap.....

took the plate off ....no capacitor...i thought mmmmm......so i get in the loft checking the connectors....nothing wrong.....so i drop a cable from the amp to the kitchen, only the one output connected.....through the loft hatch.....worked perfectly......

so i then put the splitter back on and connected the kitchen only.....it worked.....so i then connected up one bedroom to the same splitter...lost the psu again......so i went into the bedroom to have a look....

as soon as i unplug the cable from the tv everything worked ok.....so i plugged the other splitter in and connected the other 2 feeds....perfect....

so i then started to investigate....i came to the conclusion that this tv didnt like to have dc at the tuner input....but i had no way of decoupling it as i had no isolating splitters or face plates......

so i decided to try a 6db attenuator, which i thought might just lower the dc enough to be able to operate....it worked...:-worship

by then i thought thank god for that.....i went round checking the signals in each room and got to the living room and the signals were really low, due to the really old cable being used,(multicore centre) so i then had no other option but to run a new cable to that room...customer wasnt happy but i explained......

is this going to be common with some tvs regarding my problem.?

cheers chris

 

[rolfw]

I've had a few TVs throwing out voltage from the aerial input, a DC blocker normally solves the problem, always carry a few in my van. I've also got some single leg power pass "F" splitters which do the same thing.