Hi everyone I have an acoustic solutions hi-fi amplifier that I've had for years and it's always been good to me until yesterday it suddenly stopped working, so I opened it up and noticed on the circuit board there were a few tacks in some of the tracks so I re-soldered them and also found a bad fuse by chance which I also replaced. But when I turned it on the LCD illuminated but wasn't showing anything and there is a loud buzz coming from the transformer... I turned it off and started looking for any bad components but I haven't noticed any by eye that are blown however I have noticed a resistor that's sort of flaking a bit but when I used my multi meter it seems fine... Does anyone know how to help me sort out this problem?

 

Hi everyone I have an acoustic solutions hi-fi amplifier that I've had for years and it's always been good to me until yesterday it suddenly stopped working, so I opened it up and noticed on the circuit board there were a few tacks in some of the tracks so I re-soldered them and also found a bad fuse by chance which I also replaced. But when I turned it on the LCD illuminated but wasn't showing anything and there is a loud buzz coming from the transformer... I turned it off and started looking for any bad components but I haven't noticed any by eye that are blown however I have noticed a resistor that's sort of flaking a bit but when I used my multi meter it seems fine... Does anyone know how to help me sort out this problem?

Most age related failures are capacitors. If you have a schematic someone might have some ideas on where to look.

 

These are some pictures of the circuit boards

 

I know you want to fix your old friend but you should look at what used gear sells for on e-bay. You might spend s lot of time to fix something worth $5. Spend $20 and get a big upgrade.

Those flaky resistors are unusual. Could definitely be a clue. As suggested, it's probably bad caps. The easiest thing is to just replace every electrolytic on the board. Think of it as maintenance. If a problem persists, you may be stuck. A schematic and service manual would help a lot.

 

But when I turned it on the LCD illuminated but wasn't showing anything and there is a loud buzz coming from the transformer...

Sounds like a faulty (low-Z) Cap shorting the PSU --- FWIW I'd just replace all the large electrolytics in shunt with the power supply...

Good luck!
HP

 

Hi everyone I have an acoustic solutions hi-fi amplifier that I've had for years and it's always been good to me until yesterday it suddenly stopped working, so I opened it up and noticed on the circuit board there were a few tacks in some of the tracks so I re-soldered them and also found a bad fuse by chance which I also replaced. But when I turned it on the LCD illuminated but wasn't showing anything and there is a loud buzz coming from the transformer... I turned it off and started looking for any bad components but I haven't noticed any by eye that are blown however I have noticed a resistor that's sort of flaking a bit but when I used my multi meter it seems fine... Does anyone know how to help me sort out this problem?

What is a "tack in the track"? Where's the picture of that? What do you mean by "flaking resistor"? Where is the picture of that? Did you even bother to do any voltage measurements?

You will probably find your problem on that giant heatsink wall, specifically, the main stereo amplifier.

 

Agreed on the electrolytics. With the age of the unit, it might not hurt to look over all the solder joints as well and make sure there are no broken or loose joints. Do you have an ESR meter to check them or even a capacitance meter? Both of these will tell you if you are on the right track.

 

Hello,

Those resistors that gone flaky might be due to to much heat aka. power dissipated in them.
It could be that the caps make to large ripple wich could cause this.
When you replace the caps, I would also replace the resistors.

Bertus