# STKs - Better to wait or be proactive?



## SLR_65 (Mar 14, 2010)

Just wondering . . . if you have a 5+ year old RPT with the STKs in it is it best to wait for them to go out or is it best to be proactive and just replace them? (i.e. is there a danger of further damage (beyond the usual resistors and fuses) to other components that would be hard for the average DIYer to diagnose and fix if you wait for them to go out?).

Thanks!

Steve


----------



## lcaillo (May 2, 2006)

Don't try to fix something that is not broken.


----------



## SLR_65 (Mar 14, 2010)

Thanks Leonard!

I do generally follow that principle and was just wondering if there was a reason to break from it or not.

I used to have a troubleshooting flow chart that started with "Does it work?" if yes it said to leave it alone, if no the next question was "Is that because you messed with it?" 

Thanks again, g'night,

Steve


----------



## lcaillo (May 2, 2006)

That would be good advice. People who don't work on electronics on a daily basis don't realize how easy it is to create a problem. Even with care and attention to detail, you might upset a weak connection or change wire dress, or damage a trace with repeated soldering. You might even get a bad replacement part that does not last as long as the original might. 

What I would do is clean the lenses and mirror and align the focus and convergence carefully.


----------



## SLR_65 (Mar 14, 2010)

Hi Leonard,

Thanks for the advice.

I was just wondering if it were kinda like a timing belt in a car - they are difficult to get to so you don't want to change them any earlier than you have to, but you also don't want to wait too long as it can do significant damage if it does break.

From what I gather then when the convergence amps go out the majority of the time it's just the chips and maybe a resistor/fuse or two and nothing else usually gets hurt so it's riskier to attempt a preventative maintenance repair than it is to just wait and fix it if/when you have to.

Good to know!

Thanks!

Steve


----------



## louvain (Oct 21, 2010)

I prefer to follow that principle.


----------



## lcaillo (May 2, 2006)

I tend to change both when changing one, but do not change chips just for preventative maintenence. There has been such a problem with the quality of parts, even among what are often believed to be OEM parts, that I don't care to take the risk on something that is working. You might substitute parts from a bad batch for parts that were perfectly fine. When one fails, then they are both suspect, and particularly if the heat sinking is not done well or the paste dried it often makes sense to do both. 

The other problem with changing parts as prevention is that many people actually CREATE more problems when doing so. You can read through the archives here and see many who had problems after trying these repairs. Even professionals sometimes blow a chip or miss something, or crack a solder joint somewhere else just moving and flexing the boards. It is VERY common for novices to not check all of the things that I recommend in the sticky, or not understand how to install parts properly. It is also common that people buy parts from suppliers other than those recommended, believing that they know what they are doing, and get bad parts.

Generally, don't fix it if it is not broken. Unlike a timing belt in a Honda, you won't damage much else if STKs start to fail. Now if you run it for a long time after problems start occurring, that is another can of worms.


----------



## merc (Oct 3, 2009)

Based on my experience, you need to buy the parts now and worry about repairing it later.

I have a 8 year old CRT HDTV and an 18 year old sportscar, and wish I would have bought the parts which I've seen failing on newer units from other folks before they needed to be replaced on my stuff.


----------



## lcaillo (May 2, 2006)

If one buys parts in advance of a problem there is the risk of other failures that may make the set impractical to repair. In that case the parts may be useless. Had one bought STKs several years ago, however, the prices may have been lower. It is simply a matter of whether you want to tie up your money or not and whether one considers the opportunity cost.


----------

