Thread: Philips N4450
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Old 21st Oct 2017, 2:32 pm   #61
TonyDuell
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Join Date: Jun 2015
Location: Biggin Hill, London, UK.
Posts: 5,188
Default Re: Philips N4450

For those who are following this saga...

I eventually decided on the 3 core mains lead. I wired a short length to the machine (earth to the marked screw next to the mains input bush) and fitted it with the plug half of an in-line connector. A longer length from the socket part of the connector to a BS1363 plug (3A fuse, of course). And I did make up a short 2-core adapter cable I can put between them if I ever want the thing floating. But I consider removing safety earths to be the wrong way to cure earth loops, perhaps that should be a different thread...

I did check the insulation between the current-carrying wires and ground (with the unit's mains switch on, of course). Around 200MOhms at 1000V. So I am not worried that there's excessive leakage.

Time to try it out. Two nasty faults, the right channel was missing and some of the illumination bulbs went out when I pushed a DIN plug into one of the sockets. It was the force of doing that that slightly bent the amplifier motherboard that caused the bulbs to go out, nothing to do with the DIN plug being connected to anything.

That was due to a cracked track on the PCB that was trivial to cure once I had found it The lost channel was thost Philips slide switches again. I found the offending part (just has 6 terminals to switch the amplifier input between the tape recoder part (most modes) and the output of the 'before tape' pre-amp (in amplifier mode). So I desoldered it, cleaned the contacts again, and slightly bent the fixed contacts inwards. It now seems OK... I played back a scratch tape with no problems

Need to check recording on this machine. Also need to sort out a trim strip for the cover.
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