NAD 4225 Tuner. Not all it’s cracked up to be

This beauty was acquired from a well known high street pawn brokers for £20. A bit dirty, but otherwise working fine. As usual with 2nd hand purchases the lid had to come off for a nose about inside.

Didn’t expect to see that. A Jaffa Cake box? It didn’t start up either, well, not until I pressed on the Jaffa Cake box.

With the cardboard removed if found that pressing down on the circuit board with an insulated screwdriver, about where the box was, caused it to start up. I’m guessing that this is about as far the last person inside got before stuffing his face with biscuits (or are they cakes?) and cramming the box inside his tuner to make sure it powered up. What were they thinking! DO NOT TRY THIS AT HOME. 

The first thing is spotted was that all is not well with the fuses in there. This one is lose in it’s holder and the wrong value. I found a similar story elsewhere on the board. Don’t mess about where fuses are concerned. Their purpose is to protect equipment and life. Always fit the correct type. So, I did. I also replaced the fuse holders because I happened to have some of the correct type to hand. My tuner is now a lot safer, but it still doesn’t work. So that wasn’t the main fault. The thick wires there carry mains. I’ll be re routing them later.

A good visual inspection, pushing and pulling on components and wires to try and identify something lose, was fruitless. The circuit board had to come out. Not too bad on this. A thorough inspection showed a couple of tracks near one of the mounting holes which didn’t look too good. I cleaned the tracks up with IPA and a fibre brush and discovered this crack in the board. Testing with a meter confirmed that the tracks were indeed broken, and flexing the board caused them to make contact.

The fix involved cleaning thoroughly and applying fresh solder along the breached tracks. A little glue was then applied to the board as a belt and braces.

While I had the opportunity I re routed some of the mains wiring inside, so it didn’t go through the main PCB. This was to make it a little safer for the next person who goes inside, which will probably be me. I then put it all back together and tested. All good and in daily use as part of my main HiFi system