Capacitor ID

[humble]

Hello All,
My remote is not working but all the buttons on the TV work OK.
The remote's I.R. output passes the camera test.
I have renewed the IR receiver even though the old one checked out ok.
The infrared detector sensor board has an SMD 2012 (metric) capacitor "C1" which I believe to be faulty. Please see attachments.
With the I.R. sensor removed no other elements are involved & C1 capacitance reads O.L. and it shows 1.9 ohms resistance.
The cap has no value on it & after many hours I have been unable to find a schematic with its value.
It bridges between the board's 5v power supply & ground.
The TV is a Toshiba 32AV500A. (Australian release)
Can I remove C1 for good with no long term ill effects?
Is there a generic value that I might substitute?
Or if someone can point me to that particular C1 value I would appreciate it very much.

[CapLeaker]

Re: Capacitor ID

Either a 0.33uF (input) or a 0.1uF (output) depending.

[humble]

Re: Capacitor ID

Thanks for your reply CapLeaker.
I am not sure of the significance of input & output.
The 5vDC to C1 is input supply from the power board via pin 1 of the the 6 pin socket on the IR board & through R5.

[stj]

Re: Capacitor ID

that cap is pretty big, i suspect it's more like 10uf!

[SteveNielsen]

Re: Capacitor ID

The 5v would be the input, so he's saying try a 0.33uF cap there and a 0.1uF on the other. The one missing in the pic is the output.

Many IR detector circuits don't use caps at all, I think you could try it without C2 and see if it functions.

[humble]

Re: Capacitor ID

Stj, The photo does make it look big.
It measures 2,0mm long & 1.3mm wide (2012 metric form)
Very general specs give those ceramic SMD caps 1nF~100uF if you call it light brown or 10nF~1uF if you call it medium brown. The adjacent resistors are dark brown.
Steve until your post I did not realise that C2 was missing! The gap measured 0.2 nF
I will try to buy 0.33uF & 0.1uF SMD tomorrow (in backwoods Adelaide ha ha)
Failing that I may have to substitute a wired alternative.
Thank you everybody for your replies.

[SteveNielsen]

Re: Capacitor ID

I misunderstood. I saw C2 missing and thought you'd removed it and it was the bad one. My brain fart, sorry. Anyway, either way, try it without C1 and see if it works if you want to. I don't think it will do any damage to try. I believe it is there to help smooth transient switching currents and the circuit may basically function without it.

[humble]

Re: Capacitor ID

I like your workaround. Try running without the shorted C1 & the missing C2. Suck it & see. Thank you.

[jetadm123]

Re: Capacitor ID

Any chance that IR detector has a part number? If yes, then you can can look up the datasheet for it. Usually the manufacturer will include a circuit for setting up that detector.

[humble]

Re: Capacitor ID

Yes, good thought.
Original IR detector is
5B89
53A
I had Googled it but got no hits.
Not having brand name didn't help. However the replacement came from Jaycar
Catalogue No. ZD-1952.
Just found its data sheet but no capacitor details.

[CapLeaker]

Re: Capacitor ID

If you want, change it over to electrolytic. Capacitance is not that critical there, but is surely would something back in. The only problem is to obey the polarity when you do change it over to electrolytic anything between 0.33 and 1uF should do the trick.

[stj]

Re: Capacitor ID

if you change the sensor, dont mix up 5v ones with 3v ones.

[humble]

Re: Capacitor ID

Thnx stj.
I managed to buy smd caps but they made no difference.
With the IR board back in the tv the IR board frequency outputs from pressing the various remote buttons match those on another (good) Toshiba; e.g. with the Fluke set to DC volts & frequency, "power on" remote button =18.42Hz, "menu" =18.27Hz, "5"=18.35Hz etc.
I assume this is how the buttons are differentiated.
Next step seems to be to follow the signal to the main board.
Lacking a specific wiring diagram I expect it to lead me to a 48 leg IC & no idea of which output leg I need to test.
As Australian bush ranger Ned Kelly said before he was hung, "Such is life", but as the copper that wounded him may have said "The thrill is in the chase"

[stj]

Re: Capacitor ID

maybe it's just the cable!

[humble]

Re: Capacitor ID

Fixed.
With the new IR input sensor & 0.33uF input cap but no output cap (there never was one) everything works OK.
Perhaps the new IR sensor was unnecessary but it was a cheap first step.
Many thanks.

[CapLeaker]

Re: Capacitor ID

great to hear!