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remote control - the right way to fix it

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itaishi

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hi everyone,
(hope i am in the right section with that unsolved issue)

the issue : Fixing a faulty Remote Control.

i have a remote control of a DVB-T (Hyundai HY-2806), that suddenly had stopped functioning.

the right steps to check it (as for my opinion) :
1. Replace to Remote batteries for a new pairs - still not functioning.
2. i brought a same remote model from someone, tried it , and its work perfect
conclustion: - the DVB-T is ok, the Remote is faulty.
3. remote's LED output check:
put the remote in front of a camera (The LED towards the camera)
now press some buttons on the remote,
if on the camera we see the remote's LED lights on and off, so the remote is somehow functioning.
if no lights seen on the camera, so the remote is completely dead - this is my case.
4. i openned the remote and solder again all the solders on the PCB ,
put back all the parts, and tried again - still nothing.
5. now i am on a dead end:
on the PCB, only 3 chips/parts :
a. the LED
b. a chip called HS 455E (is it a kind of oscillator?)

**broken link removed** **broken link removed**

c. the "Brain" or CPU, dont know how to name it , and it is hiding under a black , inflexiable big dot.
is there way to know what under it?

any suggestions of what else can be done?

remote1.png
remote4.PNG
remote3.PNG


thanks,
itai
 
As it's outputting flashes (of some kind) a common fault would be a broken ceramic resonator (the HS455E), one or more of the leads often snaps off due to the remote been dropped.

Often you can solder a piece of wire on, and repair it - and use a piece of double-sided tape to secure it to the board.
 
As it's outputting flashes (of some kind) a common fault would be a broken ceramic resonator (the HS455E), one or more of the leads often snaps off due to the remote been dropped.

Often you can solder a piece of wire on, and repair it - and use a piece of double-sided tape to secure it to the board.

hi Nigel,
thanks for your answer,
just to be sure i understand you well,

maybe i didnt was o clearly in my explaination,
i ment that The there is no Flashing output of the LED at all.

so you said it can be one of the leads or the resonator,
is there any way to check the resonator?

thanks,
itai.
 
hi Nigel,
thanks for your answer,
just to be sure i understand you well,

maybe i didnt was o clearly in my explaination,
i ment that The there is no Flashing output of the LED at all.

so you said it can be one of the leads or the resonator,
is there any way to check the resonator?

Sorry, I misunderstood.

The only way to check the resonator is by replacement.

If there's nothing at all from it?, it could be the IR LED that's faulty, it's a fairly common fault.
 
Sorry, I misunderstood.

The only way to check the resonator is by replacement.

If there's nothing at all from it?, it could be the IR LED that's faulty, it's a fairly common fault.

so i get another new IR LED,
but i dont know if it is a good replacement for the existing one.
looking clothly, its not look the same,
i see that IR LED are misured by nm (e.g 940NM, 840NM)
is there any serious different spec between them?
or all of them can fit and pretty make the job ?

IR LED2.PNG
IR LED.PNG
IR LED3.PNG
IR LED4.PNG
 
The most likely faults with remotes are:

(1) High resistance in the supply line from the battery- a thin film of corrosion builds up and stops the very low current consumed by the controller from flowing. This is why it is necessary to spin controller batteries every couple of months or so to cut through the corrosion barrier on the battery and contacts.
(2) Cracked traces, especially as the PCB is normally poor quality, badly mounted, and also controllers get dropped.
(3) Shorts between traces. These are sometimes crystal growths.
(4) Keyboard failure, often due to dirt or cracks
(5) Resonator failure as Nigel says
(4) LED failure
(5) Any other component failure including cracked resistors

(1), (2) and (3) are the most likely.

To investigate:

(1) Make sure there is a supply voltage from the battery on the relevant traces on the PCB. Use a needle to penetrate the solder resists.
(2) Scrub both sides of the board with a stiff non wire brush soaked in isopropyl alcohol (IPA). Place the board in an oven at around 65 deg C for 4 hours.
(3) Inspect the board for cracks/shorts with a x20 magnifying glass or loupe.
(4) The LED can be tested by passing about 2 Ma through it and making sure that it illuminates.

spec
 
Simply take an LED out of another remote control, and use that.

The actual spec of the LED makes very little difference, I can't even remember the ones I used to use as replacements - apart from they came from RS Components, I certainly never consulted their specifications.
 
The #1 reason I have seen remotes stop working is an accumulation of oil layer on the PCB under the buttons. You have to clean the board and the inside of the buttons with contact spray cleaner or non-chlor brake cleaner. The #2 reason old remotes quit working is the carbon content wears off the button where it contacts the PCB. They make a liquid to apply to the contact area of the buttons to restore performance.
 
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