Neil Robinson
Registered
A small personal triumph and a case of third time lucky yesterday.
I've looked at three of these boards over the last couple of years. The first two were totally dead and had let the magic smoke out with at least three surface mount components visibly overheated on the first with greater visible damage to at least four components on the second. Both were deemed to be beyond my skills to repair. In each of these cases the boards had been overloaded by a contaminated motor drawing way too much current.
This last example was different. Both motors and all lighting were fine and on analogue the loco ran happily in one direction but there was a dead short in the other. Unplugging everything and feeding DC to the track input pins confirmed that the problem lay within the board. A quick check on the four main rectifier diodes with a multimeter confirmed my suspicion that one had gone short circuit.
Fortunately these are amongst the few conventional through hole components on this board so I was able to remove the duff one and replace it with one from a condemned board.
These diodes have a continuous rating of 50V 5A 5W, so overloading wasn't the reason for failure. The loco was a recent ebay purchase that had been a shelf queen and subsequently only briefly test run so I guess the diode had been dodgy from the start.
I've looked at three of these boards over the last couple of years. The first two were totally dead and had let the magic smoke out with at least three surface mount components visibly overheated on the first with greater visible damage to at least four components on the second. Both were deemed to be beyond my skills to repair. In each of these cases the boards had been overloaded by a contaminated motor drawing way too much current.
This last example was different. Both motors and all lighting were fine and on analogue the loco ran happily in one direction but there was a dead short in the other. Unplugging everything and feeding DC to the track input pins confirmed that the problem lay within the board. A quick check on the four main rectifier diodes with a multimeter confirmed my suspicion that one had gone short circuit.
Fortunately these are amongst the few conventional through hole components on this board so I was able to remove the duff one and replace it with one from a condemned board.
These diodes have a continuous rating of 50V 5A 5W, so overloading wasn't the reason for failure. The loco was a recent ebay purchase that had been a shelf queen and subsequently only briefly test run so I guess the diode had been dodgy from the start.
