A friend has a good sized permanent layout that has 30 year old Lionel tubular track throughout. He's been chasing a short circuit (most likely in one of the track sections) for many weeks. For now, the Circuit Breaker in his PH-180 “brick” trips appropriately each time he turns the PH on. Is this safe, or is he rapidly diminishing remaining “trips” in the undetermined life span of the CB?
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An ohmmeter will do the same diagnosis without the worry.
No immediate danger of killing the PH180, but eventually you will kill the relay, so I'd take John's advice.
One way to find these is to use a current limited supply to power the track and then use a voltmeter to find it. It's more effective than an ohmmeter as a rule.
The ohmmeter is a tool to tell you the short still exists. For lack of John's current limited power supply, divide and conquer comes into play, unless you have blocks. You have to divide the layout in half, determine which half has the short, then divide that half again, and so on until you find it. Blocks will make this much easier, as you just keep disconnecting them until you find the one with the short.
John, what would be an example of a current limited supply?
Where is the relay? Inside the PH 180?
@John H posted:John, what would be an example of a current limited supply?
I have bench supplies that have current limiting. For something like this, passing a couple of amps through the circuit allows you to simply look for where the voltage is at the minimum, that's close to the short. Note the relay at the top of the diagram.
@OddIsHeRU posted:Where is the relay? Inside the PH 180?
Yes, there's a 10A relay in the PH180 that interrupts the current when the electronic sensing circuit detects the overload.
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