Replacing the 10V caps with 25V caps is perfectly fine. In fact, if it was manufactured like that, those caps may not have blown.
Replacing a 680uF with a 1000uF could be problematic depending on it's function.
680uF is pretty specific when 500uF and 1000uF are much more common and therefore cheaper - one would think that the engineers would have tried using those in the design rather than a 680uF - makes me think the value of the cap is important to the frequency of the circuit it's in.
Other concerns might be whether he got any of them in backwards or not.
That's a rookie mistake, but still an easy enough one to make (for a rookie).
Also, with that many swollen caps, I wonder if there were any that leaked out the bottom before swelling at the top (IE - if some caps were missed in the replacement procedure)
Also, with that large a number of caps gone, other components may have been compromised or blown.
I'd be testing the transistors around those caps (most likely punched through rather than open), looking for fusible links (surface mount fuses, 0 OHM resistors) that may have opened up etc.
The initial attack on the problem was basically correct, and in many cases probably would have fixed it (if say the 680uF cap was functioning as a ripple filter).
But when that didn't fix it, a deeper analysis should have been done to complete the repair (including locating a 680uF cap).
Testimonial: "Excellent and through description of recommendations."
- Polarity of new caps are correct.
- Old Caps were only swollen at top, no leaking.
- No other physical damage to board.
- Doing some research this seems to be a common problem for this model of TV / Power Board
- I'm going to replace the 1000uF with 680uF as well I'm going to replace a few of the smaller caps that are not showing swelling but could be potentialy problematic.
- resistors, transistors visually look in good shape, no heat marks etc..
I'll report here as I progress through this board and if I manage to resolve the problem.
do continuity checks on transistors in the area too, if any appear dead short from one lead to another, unsolder it and re-check it to make sure (as the transistor could be across a coil, and reading it in circuit would register a short).
Look for surface mounted 0 ohm resistors that read open. These are used as fuses.
Also look for fuses acting as fuses that are open. These may also be flat surface mount components but should at least be marked F1, F2, etc unlike the 0 ohm resistors which will be flat, black, and no markings other than a "0" on the top.
Most fuses will be green or white.
I've gone ahead today and replaced most of the capacitors that the other repair person had changed, so they are nice and short and not crowded.
Before I replaced the caps, the screen would flash with snow etc.. now with all the caps replaced nothing flashes on the screen. But still the Power sequence goes Red Light, 3 x Green Flash, Red Light and I can hear clicking sound.
So Next I'm going to test transistors, fuses
Now there a quite a few surface mount resistors on the opposite side of the board from where the capacitors bulged. Should I check the values on those too?
Forgot to mention, the clicking is coming from the Switching transformers.
look for 0 ohm resistors that may have opened, (surface mount) and burned resistors (lead mount) but especially check transistors. There's likely a pair of transistors near that transformer that are gone.
By the way I do appreciate that you are taking the time and replying, it is very much appreciated.
On the side of the board where the capacitors were blown, there are 3 Heatsinks, one long one and two short ones.
The long one has 8 transistors with thermal compound, one of the shorter has 3 and the last one has just 1.
Some have 2 Prongs, 3 Prongs and 4 Prongs.
Can I test these in place? or will I have to unsolder and remove them? Some of the transistors have components in-front so if I have to unscrew them I will most likely have to unsolder the caps.
I did find 2 x Green Resistors labled 00000 and they are not blown.
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