This Linn Kairn with MM/MC came in dead, apparently “was working fine and went off”.
Fuse blown so took a look at the power supply (‘Slimline’ switching version) and found a number of dead parts, including both mosfets shorted, controller and a few resistors:
I wanted to check the other component values against the PSU schematic so got in touch with Linn, and their rather unhelpful response was:
“Unfortunately, for safety reasons, we do not publish schematics for any of our PSU’s or advise on PSU repairs. The Kairn has been End of Service life since April 2009 due to us no longer being able to source all the parts required to guarantee repair.”
So as I wasn’t looking for ‘advice’ and they mention having a Slimline Service Manual referencing a Slimline Repair Procedure in LInfo I thought they’d have the schematic, and surely, safety for a repair is my concern, not theirs, and replied as such.
They flat outright failed to help, effectively saying they don’t fix them anymore and don’t want anyone else to either! Thanks, Linn.
Anyway I was just about able to read the values of the fried components which I had in stock, just needed to order the IRS2110 controller, when it arrived, it was replaced, powered up with an attached load initially slowly by variac on DBT and we have output!
Thermal imagery shows nothing out of the ordinary:
Board after repair:
Then we try the unit. Hmm still no power LED?
Arghggh:
We are getting power to that board though, but not much going on. Explains why the power supply was fried – I suspect the previous owner had switched it to 115V as a last ditch effort to see if it came on!
Not sure how far the alkaline leak damage has spread to, hopefully nothing irreplaceable has perished.
After removing the battery and checking out Q3/Q4, replacing power LED and repairing broken tracks including under a capacitor which was also replaced, we’re getting there!
Fitted new battery and returned back to service:
Thermal imagery of the main unit in use, just out of interest 🙂
