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Old 22nd Jul 2021, 12:27 pm   #4
Techman
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Join Date: Nov 2009
Location: Lincolnshire, UK.
Posts: 3,970
Default Re: Murphy A855g Record Player - Intermittent power issue.

The symptoms certainly are inconsistent.

The transformer supplies the amplifier from one of its secondary windings and the lamp from a second separate winding.

Seeing that circuit clip reminded me that this is the model that's notorious for its mains transformer burning out. There have been several of these in recent years of both Bush and Murphy models featured on the forum with burnt out transformers and none have ever reached a satisfactory repair conclusion. The problem is as to what actually goes faulty to cause this burn out in the first place and the unavailability of a suitable replacement transformer seems to cause the owners to just give up with them.

So what I would say is that with the above in mind, don't leave the player powered up for any length of time when under the fault condition, but quickly do as Graham suggested and stroke the stylus with the volume control turned fully up to see if you get noise from the speaker. If the transformer was being heavily loaded by an amplifier short circuit fault then this could possibly cause the winding that supplies the lamp to drop its voltage, but that still doesn't answer the question as to why the record deck stops working, as this is powered from the mains input primary side of the transformer.
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