Missing smd caps win-tv-pvr-500

[Mad_Professor]

SO I bought a wint-tv-pvr-500 off ebay, turn out it was defective.

This is a dual ntsc tuner for those that are not familiar.
It has two mpeg encoding chips on it.

Tuner 1 worked perfectly
Tuner 2 no picture but got sound.
I took a closer look at the board and saw missing smd caps on the backside opposite of the conexant chips.

Photos below of board and what the tuner does in mythtv

How can I find the values for the missing caps?

[mariushm]

Re: Missing smd caps win-tv-pvr-500

Those are decoupling capacitors, and usually there's no reason they would be of several values. The usual values for decoupling capacitors are 0.01uF , 0.1uF, with a decent voltage rating (25-50v maybe)

The value is probably the same as the ones around (c90 to c102), desolder one and measure it and you will know

[Mad_Professor]

Re: Missing smd caps win-tv-pvr-500

Those are decoupling capacitors, and usually there's no reason they would be of several values. The usual values for decoupling capacitors are 0.01uF , 0.1uF, with a decent voltage rating (25-50v maybe)

The value is probably the same as the ones around (c90 to c102), desolder one and measure it and you will know

How do I measure it?

Also what's the proper name for them, ceramic, tantalum?

What would you recommend for replacement?

[mariushm]

Re: Missing smd caps win-tv-pvr-500

You obviously measure them using a capacitance meter (after desoldering it from the board). Some digital multimeters have this functionality, but a lot of the cheap ones are inaccurate.
I have a Uni-T UT61E multimeter and it works great.

The small light brown capacitors are ceramic capacitors. The yellow ones in the center are tantalum capacitors and the brownish line on one side is the POSITIVE side.

I recommend that you MEASURE the capacitors first but if you're really unable to do so, then go for 0.1uF 35-50v, maybe 25v if you really can't get them in that small size.

You can search digikey in the "ceramic" capacitors section: http://www.digikey.com/product-searc...acitors/131083

Measure the width and length, filter by those on digikey. There's various standardized size, those are probably 0402 or 0603 (see http://en.wikipedia.org/wiki/Surface...ology#Packages )

Then pick from temperature coefficient C0G,NPO , X7R, X5R - these are classes of capacitors that handle temperature better and the capacitance doesn't vary so much.

Then pick the voltage range, choose 25-50v, worst case 16v if you have hard time finding suitable ones (even if that chip works with 1v-5v, it's important to have the max voltage much higher)

[budm]

Re: Missing smd caps win-tv-pvr-500

MLCC- Multi Layer Ceramic Capacitor.

[Mad_Professor]

Re: Missing smd caps win-tv-pvr-500

I don't have a capacitance settings on any of my DMM's nor esr meter.

I wonder if there is a datasheet for the cx23416 chipset,
maybe I can figure out what the decoupling caps were.

[mariushm]

Re: Missing smd caps win-tv-pvr-500

Can't you just get a cheap digital multimeter and be done with it?
After all, you're active here, sounds like you could use one.

Here's a cheap one, unknown brand:

http://www.amazon.com/niceEshop-Digi...tal+multimeter

Just capacitance, still cheap:

http://www.amazon.com/DBPOWER-Newcas...ds=capacitance


http://www.amazon.com/Elenco-Digital...ds=capacitance

[Mad_Professor]

Re: Missing smd caps win-tv-pvr-500

I might have to hold off for now, money is tight, I got a cat at the vet and you know they are going to milk me. I got two cars that need work, I need to pay down my credit card, it's getting out of control, My job is trying cut back on hours because of the bullshit obamacare, government, greed, fuck me with a broom stick. and I'm trying to expand my business to make up for the lost income.

Also I got a full refund on this card so now it's free.

I'll have to fit it in my next months budget.