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TonyDuell · 13th Aug 2017, 2:43 pm

And today's lesson is 'Don't cut corners!'.

Having got the amplifier back together I tested it to find it was dead on one channel. An imput signal got as far as the monitor socket but no further. Testing signals on the amplifier motherboard suggests more potentiometer trouble. Possibly squirting propan-2-ol into them moved some muck onto the track/contacts.

So I have stripped the amplifier again and am cleaning and testing all the pots and switches (might as well do the latter while it's apart. Then I can look for real faults!.

The pots are not in good condition though. The wiper is a pair of contacts in parallel and in a couple of cases one (fortunately not both) has broken off. If I could get replacements I would fit them.

Also Philips left long bare ends on the wires after soldering them. I am cutting those off as a couple looked as though they might short to something. They can't have any electrical purpose.

13th Aug 2017, 2:43 pm	#45
TonyDuell Dekatron Join Date: Jun 2015 Location: Biggin Hill, London, UK. Posts: 5,225	Re: Philips N4450 And today's lesson is 'Don't cut corners!'. Having got the amplifier back together I tested it to find it was dead on one channel. An imput signal got as far as the monitor socket but no further. Testing signals on the amplifier motherboard suggests more potentiometer trouble. Possibly squirting propan-2-ol into them moved some muck onto the track/contacts. So I have stripped the amplifier again and am cleaning and testing all the pots and switches (might as well do the latter while it's apart. Then I can look for real faults!. The pots are not in good condition though. The wiper is a pair of contacts in parallel and in a couple of cases one (fortunately not both) has broken off. If I could get replacements I would fit them. Also Philips left long bare ends on the wires after soldering them. I am cutting those off as a couple looked as though they might short to something. They can't have any electrical purpose.