Which soldering iron to repair TV? New capacitors?

esuhl

I have an old temperamental TV that won't turn on unless the room is heated to 21C or above.

There are about four capacitors on the circuit-board that have blown, so I thought there's a good chance that replacing them will fix the problem.

I've never done anything like this before, so I was wondering if someone could recommend a soldering iron? It'll really just be for this one job, so I don't need anything fancy or durable.

I presume the capacitors will have their specifications printed on the side, so I can just buy identical replacements...? Is there anything else I should know before attempting a repair?


Cheers :-)

Cornucopia

Have a look on Youtube as there are tutorials covering exactly this fix (which is relatively common).

Yes, the Caps will have their specifications written on their sides. There are two values for these large electrolytic capacitors - the capacitance (something like XXXuF(microfarads)) and the voltage (XX Volts). You should aim to match the capacitance value exactly. The voltage should either match or the new caps can have a higher voltage (but never lower). Electrolytic caps have a positive and negative connection and the replacements must be connected in the same orientation.

Use a fine-tipped soldering iron, with a rating of 15-30W.

If you've not done any electronics work before, this is quite a bold choice for a first project. Be aware that some components may hold a charge even when the device is powered off (less of a concern with flat screens than CRTs, but still something to be aware of).

Inner_Zone

Just to add to the above the current capacitors will probably be marked 85 deg C, try to get 105 deg C replacements for longer life.

System

I'd go for a higher rated iron than 15-30W so you're applying the heat for less time to melt the solder which reduces the chance of lifting the pads off the PCB. The lower the wattage the longer you end up having to leave the tip on the solder for it to melt through.

You'll also need a solder sucker or desolder braid. The solder sucker is probably the easier to use of the two for a newbie.

If you find the solder isn't melting add some more, that usually kicks it off.

esuhl

Thanks, everyone -- that's all been really helpful! :T

Cornucopia wrote: »

Be aware that some components may hold a charge even when the device is powered off (less of a concern with flat screens than CRTs, but still something to be aware of).

Yes, thanks. I actually have an AS-level in Electronics, so I sort-of know the basics, but... that was a long time ago!

glennevis

I'm pretty sure I saw a soldering station in Aldi (or was it Lidl?) 'specials' recently. They might have gone by now, of course. I have plenty of soldering irons so didn't check the rating but it was probably at least 60W which would do the job.

Owain_Moneysaver

You can get proper leaded solder from CPC (and probably the capacitors too).

See here for safe discharging of capacitors and if it is a CRT tv note the tube can hold a charge of 25 kilovolts or more

Frozen_up_north

I have used an Antex XS (25W) iron for years. The one with a silicon cable is nicer than the PVC one. While there are cheaper irons, an XS will be useful for a lifetime.

Geodark

esuhl wrote: »

I have an old temperamental TV that won't turn on unless the room is heated to 21C or above.

There are about four capacitors on the circuit-board that have blown, so I thought there's a good chance that replacing them will fix the problem.

I've never done anything like this before, so I was wondering if someone could recommend a soldering iron? It'll really just be for this one job, so I don't need anything fancy or durable.

I presume the capacitors will have their specifications printed on the side, so I can just buy identical replacements...? Is there anything else I should know before attempting a repair?

Cheers :-)

Samsung by any chance?

virgo17

Geodark wrote: »

Samsung by any chance?

I wondered that too! :rotfl:

esuhl

Owain_Moneysaver wrote: »

You can get proper leaded solder from CPC (and probably the capacitors too).

Thanks -- I'll check them out.

Owain_Moneysaver wrote: »

See here for safe discharging of capacitors and if it is a CRT tv note the tube can hold a charge of 25 kilovolts or more

Much appreciated. I know how to discharge a CRT tube safely, but I've never tried. I'm quite risk averse (I don't even use power tools!).

Fortunately It's an LCD panel, and all the capacitors are pretty small. I'm confident that I know enough to not put myself at harm...

Geodark wrote: »

Samsung by any chance?

No -- an LG. It's never worked properly -- freezes, crashes, glitches. It was repaired under warranty twice in the first year, but the engineers didn't seem to diagnose anything -- just made a guess, swapped a component and left with it not working any better. Grr!