PH-180 6-22983 Circuit Breaker

Is this a new PH180 or one of the first generation ones from a few years ago?  The ones from a few years ago should reset with a power cycle or pressing the button.  The new ones "should" work the same, but you're about the 3rd person that has had an odd issue resetting one if you have a new one.

Hi John.  The date ingraved on the underside of the unit is 2007 10.  So I have a bad brick, or at least on with a bad CB?   Just to continue testing my layout i hooked up my MTH Z1000 brick and all is working fine.  But I’d really like to get the PH 180 I invested in working

Yep, it'll have to come apart to see what happened.  To help in that process, here's the schematic of the internal breaker board.

Note that there is also an internal fuse in the windings of the transformer core from what I've been told.  I haven't personally ever had to try to find it and have never had the core fail, but that's the story.

My experience has been with the few I've repaired that the repairs centered around the 8V power supply and the relay.  I know some folks have had the switch fail, but a power cycle should bring the transformer back to life even if the switch was bad.

A couple of schematic notes about the circuit operation:

In the schematic, both U1b and U1c are amplifying the current sense signal from L1 the current sensor.  U1c, the "overload" detector, has a gain of 148, but it is slowed down by the resistor and capacitor on its output.  The time constant (RxC) is 2.6 seconds.  Multiple short hits to this RC combination would charge it up until it trips the relay latch.

U1b has a gain of 37, which means it requires 4 times as much current, but it acts instantaneously for "dead short" situations.

Hi John,

While I am also a retired engineer that worked aerospace, I was a systems engineer and ops analyst.  EE not my forte’!   I’m not the right guy to rip this thing apart and start diagnosing the problem.   In your opinion, is this worth shipping off to get repaired?  Shipping alone to and from is likely to set me back $60

Truthfully, I doubt it'll be cost effective to have someone repair it if you have to ship it.  If you're going to ship the PH180 transformers, they need some super packing, the heavy core tends to destroy the transformer if it's not really well cushioned.  With the two-way shipping and repair costs, just buy a new PH180.

For a lot of my later life in engineering, I was doing the systems work and not actually the down-n-dirty electrical engineering.  It was kinda' fun to dust off the old training and do some electronics again.  My first engineering courses still involved vacuum tubes.

Hahaha.  I'm old enough to remember vacuum tubes.  I still recall going to the drug store with my dad where he used the tube tester and get new tubes for the TV.

While not a EE, I knew who to turn to when the expertise was needed (which was alot)!

I have another new-to-me PH 180 on order.  Prices not bad on the 'Bay

Boy, gone are the days when I was buying these on OGR for $50/ea!