Hi all,
I've been doing a few of these recently and had one with a bad 5V supply. The LAS1905 is a 5V, 5A regulator but this one decided it was going to be a 6V one! Looking at the state of it I'm not surprised!
Trying to source these devices is a pain and the only ones I've found are so expensive it makes the repair uneconomic. That's excluding the usual Chinese knock off's of course as I wouldn't touch these with a barge pole!
With nothing to lose I thought I'd see what else was available. The only 5V 5A I could find was an LM1084. This is in a TO220 package so a cunning plan was needed to get it to fit as a replacement.
I eventually ended up with this....
This was the only way it would fit using the existing holes and heatsink.
The legs had to be crossed over and wired into the board.
On test it appears to function fine and you can still utilise the adjustment pot for fine voltage tuning. It should be a much more reliable device and it's cheap too.
A few points to note are, the tab is not the ground so has to be insulated from the heatsink and the retaining screw. Because the board hole is larger than the screw used to hold the new device it really needs a bush to keep it centered.
Hope this is useful. 
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