Anyone idea of the temperature required to make the heatshrink label wrapper of a small radial electro shrink down the cylinder, requiring stretching the shrunk end, sliding over the rim, before sliding down the cylinder part. ?
How much is down to conflict between power supply designer and EMC compliance bod? Designer: I want convection vent holes here, here and here, through the shielding EMC bod: No way, I can let you have a few holes here and thats your lot
Just repaired an LCD monitor, probably started failure with ESR'd caps then ohmic zener and eventually blown backlight inverter pair of transistors and blown fuse. Plenty of holes top, side and bottom of the shield on the digital processing side but only holes at the top on the ps side. So air comes in on the colder side at bottom rises to the top by about mid board and little or no air traversing the hottest section, that whole section in a dead-zone in more ways than one, brilliant
Any cap with shrinking plastic film is ready to be replaced. Figure out what circuit it is in and find either a low ESR or low Inductance (or both) cap to replace the poorer original one.
We put fans on any LCD screens that we install in any sort of cabinet.
It would be nice if tiny fans were installed by the manufacturers...
John :-#(#
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They would not have to be high revs, just enough to circulate air in or out of dead zones like between heatsink plates. In this case the hottest as evidenced by the shrunk sleeves , were from between a U of heatsinkery. I will try controlled heating of one of the other removed caps of the same make to see what temp it must reach to axially shrink the wrappers. Do they make miniature longitudinal fans say .5 inch diameter x 1 or more inches long ? Failing that it would be some ducting associated with standard 1 inch fans.
If no fans allowed I would have placed the ps board over the "scaler" board, assuming the whole monitor is not used horizontally
I had pulled a number of bulging but otherwise looking as original 16V,
470uF of the same date code from this monitor - make HERMEI LT 105 degree C, purple wrapper First one took to 190 degree C , wrapper shrank but not fully back over the rim. Outgassing before that and final colour very dark plum. Axial shrinkage of the fully shrunk one about 75 percent from edge of open end at top to the pin end rim , ignoring unaffected other open end at the pins Looks as though this shrinkage is a cycling cold/hot effect as the shrunk one was a plum colour. Tried another taking the temp only up to the plum colour , about 180 deg C, also visibly outgassing at that temp Comparing to additive colour of a pc monitor Hue/Sat/Lum/R/G/B unaffected purple of original 200/240/100/215/0/215 180 deg colour 200/240/75 / 165/0/165 190 deg colour 200/240/55/115/0/115ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.