JVC Plasma Repair: SMD Fun

[meetmetoday]

goodday mate thanks a million aussie's dollar:-} keep it up!

[randyfromm]

Oh my! Don't you use a plated soldering iron tip? You don't have to dress it as the copper atoms don't migrate from it. It is plated with steel.

I prefer a 3/16" chisel tip but there are many types. I haven't used a copper-tipped iron in 25 years!

BTW, great posts!

[Aussie50]

@randyfromm lol yeah its just a cheap nasty iron. i'm ordering a proper temp controlled station soon for when i re-visit a few plasma TV projects.

the advantage of the copper tip is I can machine it as fine as I want on the lathe. but then you can interchange tips on a good iron so its a moot point.

[DrMR2000]

Best way to desolder those IC without a airstation is to use lowmelt solder called "ChipQuik" it stays molten for a longer time so you can pull the IC without pulling the traces off the PCB.

[Knaeckebrotsaege]

oh crap.. i forgot..

to anyone who opens up a JVC set you MUST!! cover the light sensor on the board.

looks like a led with a foam gasket around it.

it is there to erase the eeprom if you run it open. yes a fu**ing boobytrap!!

Look in your service manual on instructions how to disable this thing.

especially careful on sets with DVI or HDMI. sensor is usually on the DVI or HDMI RF shielding.

COVER IT! or you'll delete the eeprom contents. JVC and Pioneer both have this sensor trap..

[Aussie50]

@Knaeckebrotsaege little bastards!, I don't remember seeing a light sensor on my board but its pre-HDMI stuff so it may not be there.

either way I never ran it with the can open it had to go back together before I could re-assmble the set.

[DrMR2000]

The capacitors on the right look bad, they look like they are bulging?

[Aussie50]

@DrMR2000 I think its just a visual illusion, I would have detected them immediately when I was going over it

[Knaeckebrotsaege]

is it just me or do the rightmost capacitors at 0:55 look like they're bulging..?!

could be the camera angle..

[Aussie50]

@Knaeckebrotsaege not that I cna tell, I will be having another look at that set soon, its been in the 'too hard basket' for a while now.

[Knaeckebrotsaege]

@Aussie50 try to get some help on the badcaps net forum. some real plasma experts there (i feel kinda dumb compared to them lol)

i remember that they had a thread with a similar problem there..

[Aussie50]

@Knaeckebrotsaege Thanks for the info!, ad you can tell I'm a complete noob at this but its worth a try!

[ihatespam1977]

If I were you I would invest in a Hakko 936 soldering station. Its a commercial grade temperature controlled iron with a large variety of tips available, yet its very inexpensive.

[LinuxGalore]

I usually just cut the pins with a craft knife close to the IC's main body then just clean up the pins stuck to the board with a soldering iron. Clean simple and you dont lose your landing pads.

[Aussie50]

I tried that on a few example IC's (scrap boards) and the force required to cut the pins was enough to put the knife blade into the PCB below and sever traces when the pins broke :(

if it were a fine pinned processor IC I'd do it but I didn't want to risk severing a trace with this one

[gavincurtis]

Looks like the temp IC has I2C serial data interface directly into the CPU. The I2C bus should be shared by other other IC's, so if temp is the only error reported; then that IC should be the troublemaker as it is transmitting false data.

Or one of the SMT resistors as you suggested could be bad.

If you haven't, check Vcc on the IC.

I am curious to see what resolves the problem.

[Aussie50]

I have resistors on order too, thanks for the info on this matter!

[diymania]

Will be interesting to see if this was the prollem, but it prolly aint.

Just because it spits out a error code for a tripped sensor doesent mean the sensor really is tripped, it more likely is from a voltage spike, damaging the main processor rendering any repair attemt wasted time as it´ll lileky still do the same thing after the repair or even be dead as a rock.

[Aussie50]

lol be positive man ;)

its a starting point, and never a waste of time when a new board costs $600+

[diymania]

My 42" panasonic plasma tv was less than that ;p And Panasonic is most likly better quality than jvc too.

[Aussie50]

lol the dollar difference is a bit more than that, a good quality 42" plasma is over $2500 here.

the JVC's are built by Matsushita anyway, so I think you'll find your Panasonic is the same as any JVC, with a Samsung or LG panel

[douro20]

How did you get a hold of the schematic diagram?

[V8Jagnut]

very good vid. you have a lot steadier hand than me.

[30GB]

looks like it was repaired before

[diymania]

or a design flaw corrected @ the factory.

[Aussie50]

most likely

[Aussie50]

U mean the resistor?

thats a factory mod, I don't think this set has ever been opened before to be honest.

[diymania]

Those "repair looking" resistors are inside almost all consumer products, maybe its there to make the product fail within a certain time.

[TehMG]

Nah, they're modifications that were done after the PCBs were manufactured, either to correct a design flaw or improve performance.

Rather than making a new batch of PCBs, the modification is soldered onto the existing batch of PCBs. Why waste money on a whole new batch when you can spend a little and fix up an existing batch?

It's not just done in consumer products, heck even NASA has procedures outlining how to properly perform modifications after the fact.

[Aussie50]

Agreed 100%, its not a pre made failure point like a lot of conspiracy theorists like to think. I doubt any manufacturer design a product to fail after a certain amount of time.

[gavincurtis]

Usually these mods are common in high cost limited production equipment.

I worked on a late model X-ray machine for semiconductor quality control. The boards in that machine had significant numbers of cut traces and jumper wires; parts soldered on top of others etc. Capacitors were added everywhere.

This from the factory. The boards were too expensive to discard it seemed.