Re: WTB a TDK 114H1 common mode choke
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Thanks Ed. See my other reply with photo. I think a pair of windings shorted and burnt the insulation off the other windings and caused all to short together. It must be thin wire on a toroid and now a melted blob of less than an ohm between any two pins with no pins open.? I suggest NOT following the manual where it says to disconnect the collector of the overcurrent sense transistor to disable the protection. It is safer to look for a short with an ohm meter. In this case all six rectifiers in the?+5v,?+15v, and -15v supplies appeared to be shorted (less than an ohm). I did not believe that and looked elsewhere. Pulling a connector indicated the short was off the main power supply board but still did not make sense. One shorted capacitor is not surprising, two shorted capacitors unlikely, three shorted capacitors better start thinking something different. The resistance went up as I moved away from the choke. Four shorted windings in a choke seemed impossible and I expected to find the choke OK but had to remove it to check further.?
Anyway still looking for a spare before trying to wind one. I don't like the idea of four windings touching even if varnished. Formvar is good but can it be trusted? I suppose all windings touch adjacent wires in any transformer. PeterB
On Tue, Jul 9, 2019 at 10:33 PM Ed Breya via Groups.Io <edbreya= [email protected]> wrote: Is the choke wound with fairly thin wire? It would be unusual for a CM choke to have all its windings shorted together unless it got very hot from fault current or adjacent heat sources, or by serious over-voltage between the windings. I'd recommend leaving out the choke and just jumping the lines until the cause is figured out. Rewinding or replacing the choke later should be fairly easy.
Ed
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