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New member Username: Jabberwocky006Post Number: 1 Registered: Mar-06 | Following was PM to wearenotalone69@gmail.com that I'm reposting. Thanks Alan! Toshiba 57H81; see you're experienced. Power supply going out - panel light blinks, hear relay or some such click when plugging into AC. Suggestions? Having trouble tracking down replacement supply - new baby on way, cannot afford service call. Thanks for your time. Sounds like it is a problem in the power section. What happens during the "wave" soldering process is the board with all the components is run down a "line", right into, right above a vat of solder. The components on the boards "leads" sticking down dip into the solder... Then the solder "wicks" up to the component... thereby soldering ALL components at the same time. The problem with that is when you have LARGE and SMALL items on that same board. If ALL the items are BIG, or ALL the items are "SMALL", everything is find and dandy since the TEMPERATURE, and the speed in which the board travels thru the vat can be custom tailored to get a good solder. When you have BIG and Small items you can't raise the temp too much, or other wise you'll "fry" the small items... The problem with that is that the large items get a poor solder (cold solder) and over time that cold solder develops cracks. What I'd do is to check for cold solders in the power section and then re-flow them. Each time the set is turned ON, and then off it heats up, then cools off, and every time it does so it puts more stress on the cold solder till one day it's "toast" (open circuit) PS: If you suspect a cold solder you can sometimes find out which one it is by applying "heat", or cold.. If you have one of those devices that connects up to a air line that makes heated air out one end, and cold air out the other. You may be able to use a blow-dryer to "heat" the board to isolate what solder is bad.... But more than likely if you INSPECT the board you will SEE which one it is... More than likely it is one of the BIG joints... that didn't get enough heat during the wave soldering process. If you do suspect a joint being bad, do ONE at a time.... I did one board in which I re-flowed the solders on 40 joints, before that I could "flex" (bend) the board slightly to get the set to die (or work) after I re-flowed all the joints I couldn't figure out which joint was the problem as I had to apply like 200 lbs of force to get it to screw up again.. Didn't feel like wasting a bunch of time on it so I trashed it. |