Tv Questions

[retired]

Know a little about computers but not much about the electronics in tv's . Using your basic digital tv have been having some issues that concern me and hoping maybe there is a resident Mr. Wizard or two out there . We have a cable hook up with a decoder box to unscramble signal . About two months ago i had a service call because the cable signal kept breaking up . At first it was quite infrequent then more common .

Cable guys come out and measure the signal strength at the pole and say it's ok and leave . Two days later i am calling them again . Second time around they decide it's the decoder box ( though they have no instruments to test it ) and say they will come back out and replace it . Never came back out and i still have an issue . Find out that others are having similar issues so doubt it's just my decoder box . And , also the reason they never brought me another one . :-)

Loss of signal is one thing but my primary concern is the "rice crispie" effect i sometimes get when the signal is erratic . One thing i did learn working in circuit board design and assembly is that you never want a consistent " rice crispie" effect . For those not familiar with that particular cereal it makes a snap , crackle and pop when the milk hits the flakes . Now , that's cool with your breakfast maybe but not so cool with your electronics i am thinking .

Have no "official" explanation from the cable folks other than it's some one else's fault but do recall all this started about the time they went HD . Since i don't know what going HD means revelent to satelite positioning , etc. wondering if someone else might have some thoughts along these lines . Keep in mind that like most Philippines operations they use the cheapest wiring , etc. they can get away with . Someone suggested that was to make stealing the cable less likely for the copper . Sounds a bit like a fish story to me , but who knows . :-)

At any rate , going back to the cable company i would like to be armed and dangerous . So , if there are any supply sergents out there bring me the heavy ordnance . :-)

[i am bob]

If this was anywhere but the Philippines, it might be fairly easy to figure out... Why? You said it - the quality of the material they use!

A couple things you can try.... Next time the signal goes funny:

1. Disconnect and reconnect the cable at the back of the decoder box. Check the end of the cable (I assume it's co-ax) and make sure that the connector does not have any strands of the shield across the end of the connector anywhere and that the connector is crimped on tightly but not squashed flat. Once you reconnect the cable and, if the signal is still bad, wiggle the cable and connector to see if it changes at all.
   
2. Do the same as 1. for the cable from the decoder box to your tv.
   
3. Have somebody watch the tv while you follow the cable back from the decoder box and shake it out (wiggle action about a foot or more of movement with a bit of a snap to your actions) - do this for as much of the cable as you can. Check the cable for crimps or gouges as you go as well. This could indicate a broken cable inside and not uncommon on really cheap cable. Also make sure that any excess is not wound up into tight loops - this will often break the main lead inside the cable. Nice loose loops and never smaller than a 1 foot diameter is good if you are unfamiliar with the flex ration of the cable in question.
   
4. My favourite - the "Calibrated Tap" test. Give the decoder box a couple good open handed slaps on the side. Did anything change at all? You're not doing it hard enough if the box doesn't move at least 1 inch or more. DO NOT use a rubber mallet like some people will - that will just push the box around. Experience has shown (don't laugh!) that the left side is usually the best side to tap. I fixed more aircraft navigational computers that way! Hehe!
   
5. One big thing I haven't mentioned yet is your power. Make sure that your power is reading within the specs for both the tv and the decoder. HD devices are very fussy on power as are many decoder boxes as well. Voltage, current, frequency must all fall within the specs listed on the device to work properly.
   

If these don't work, your best bet is to sit back somewhere nice outside, sip on a cold one and wait for the boys with the toys to come back.

Enjoy! :tiphat:

[FlyAway]

My first guess is always towards the cable connections. Many times a bad crimp will be the culprit.

Can you isolate it down to a certain part of the day? Does it occur during high temp and humidity?

Try positioning a fan to blow across the box. It could be heat related.

[Jake]

Find out that others are having similar issues so doubt it's just my decoder box.

Loss of signal is one thing but my primary concern is the "rice crispie" effect i sometimes get when the signal is erratic.

Have no "official" explanation from the cable folks other than it's some one else's fault but do recall all this started about the time they went HD .

Based on your excellent description of symptoms above, I would like to submit my suggestions and further questions:

A signal coming from the "pole" is a composite radio frequency (RF) which are descrambled (for authorized users) and

further demodulated by the decoder box. The demodulated signals are broken down to digital signals (logic ones and

zeros) for both HD video and audio which feeds to your digital TV via HDMI or RGB connection. Usually when those digital

signals are very weak or corrupted, you should only see a blank screen. There are no gray areas -- no snow effects or

faded picture going in or out. Either you have a nice picture or you don't. That's the beauty of digital TV.

When you mentioned the "rice crispie" sound effects, can you determine its source -- is it from the decoder box or your

TV? Is it actually "arcs and sparks" from damaged internal circuitry or is it coming from your TV speakers?

Two big symptoms stood out: others have similar problems and it all started when they upgraded to High Definition.

As Bob suggested, physically inspect the coax line all the way to the pole, if possible. The field techs should really

concentrate looking for unauthorized taps. Thoroughly inspect each and every connector, making sure the center

pin of the coax connector is completely isolated from ground. Has there been a recent digging or construction around

your immediate area?

Good luck to you -- Jake

[i am bob]

One of our local cable companies had similar issues - and were doing the same... Telling everybody that their decoder boxes were all working properly. Sometimes even entire neighbourhoods were having the same issue... What was the problem? A whole shipment of decoder boxes were received by the cable company from the manufacturer that had been returned to them for repair and then inadvertently shipped out as repaired - with nothing being done to them. The few remaining people that still had issues were almost always attributed to damage cable that had been installed by "independent" installers that the company used.

[retired]

Ok , now that the shade tree , sm toss about session has started (as my Aussie friends say ) or the bs/man thing (as my non - Aussie friends say) perhaps i need to add some clarity regarding description of the problem . Bear with me guys , as i tend to approach Philippine unsolvables from a humourous perspective .

Bob: Love the slap left side vs right approach and place it in "that not in the manual" category of which i am familiar from circuit board build up for majors like Dell , Hp , NASA , US Defense Dept. etc. Let's just say that some folks should not be allowed around electronic components in either the build or test phases even when they are equiped with "static control" devices due to an inherent over abundance of bodily electrical discharge , and yes , i was one , which was primary in my banishment to the warehousing end of the sub - contractor business . Bottom line - all cable and connectors inside the house look good in regards to your excellent "shade tree" approach , which also works well with vechicles , i might add . :-)

FlyAway: Heat and humidity may be a contributor as problem does seem to exist more during the day than in the evening but even that is not consistent . That would work as an explanation though for why we can't open one of the front gates daytime due to the metal rod that slides into a concrete pillar as heat and humidity apparently make the concrete swell , but that discussion most likely belongs in the Home abd Garden section .

Jake: Do believe you may be on the right track in regards to signal frequency/strength . The sound is coming from the tv though of course has to come through speakers . Does not occur if playing a video dvd so assume it is a cable thang ( thing for non - southerners ) . At times the screen has gone completely blank as in black , no signal at all . if i turn off set and decoder box and then use remote to turn on again you do see on the tv screen the decoder , or smart card , as they call it here , going through the searching for signal routine . Pole to the house is only about 20 meters awa so no un - authorized taps there though could be further up the line i suppose .

After further deliberation and an over night sleep i tend to think it's a cable company issue from the perspective of them receiving their signal from their provider . Little background perhaps in order . Several years ago the local cable company had competition from Dream but apparently they went away and the cable company grew quite a bit . They went through a stage of up grading equipment from an "in house" perspective . They were having some significent problems as relayed from some insiders . Along comes an expat gentleman that had helped build and install satellite & cable systems in the Middle East as a sub-contractor for gov. as well as private enterprise . He offers his experience to the local cable folks as an advisor , free , of course and as one expect the cable company does not accept . It was his opinion that the two - headed monster " saving face" was in play so he left them to their own devices ( of which many were new and imported from US , according to him ) . He pointed out that unfortunately they did not also import from the US the technicans or engineers . Reference to US only relative to this example . Could have been Aussie or European or where ever 1st world technology is developed . :-)

Now , maybe just looking for hidden things in the closet from my persepective but some observations . As i mentioned , problems seem to start about the time cable company started pushing for subscriber upgrades to HD ( which we do not have ) . Have also noticed other small tell tell signs like the ESPN logo that shows on the screen now says ESPN Philippines . Also noticed that ESPN feed here now shows some sporting events that previously you had to have another upgrade for . For instance , i paid an extra 150 peso a moth to get NFL football & Nascar racing . Don't know if ESPN basic will show NFL come fall but they are showing some NASCAR which starte Feb . All of which to me suggests the supplier the local cable company gets their feed from may have changed and perhaps that end is where the problem lies . Which may mean a shade tree discussion regarding satellite technology of which i have no clue .

Just like the weekly expat get togethers here in our neck of the woods the sm is cold and the doors , or lack there of , is always open ...

[Jake]

Oh the hell with it Retired.....let's just do the man thang and BS over some cold San Magoos!

We can decide among us (Flyaway, Bob and you) who's got the bigger hammer. Talk about

performing a vibration test.....he, he.

[Mike S]

Well they installed a new digital box finally from the analog and every now and then I get a really LOUD snap like a spark jumping form the old tube TV's when you had to discharge the high voltage to ground but it comes rarely like I said and from their box so I don't care .... picture and transmission is fine .... so mine is a different problem ... :tiphat:

[Jollygoodfellow]

Could be as you say, now HD, (High Definition), Is your TV compatible to HD? Maybe you need to re install channels to what are suitable to your TV but then again I know nothing and only guessing. :unsure:

[Steve & Myrlita]

Could be as you say, now HD, (High Definition), Is your TV compatible to HD? Maybe you need to re install channels to what are suitable to your TV but then again I know nothing and only guessing. :unsure:

Where is Tiny Tim???