Can anyone help diagnose/repair my Scythe SDAR-3000 amp?

Hi @mica45713

You can't test capacitors with an Ohmmeter whilst they're still connected in a circuit, otherwise you may also be measuring other components in the circuit which are connected to the capacitor or are in the same circuit path which will affect the measurement.

To measure capacitors whilst they are still connected you need an ESR meter.

You can measure using an Ohmmeter, if they're disconnected from the circuit but it only gives an indication whether they're still good or bad i.e. either shows a rising or falling resistance value, depending on which meter leads are connected to which capacitor lead showing that the capacitor is either charging (from the battery in the meter) or if the leads are reversed, discharging into the meter OR there's no measurement at all, indicating that the capacitor is open circuit.

Some DMM (digital multimeters) have a capacitance test function that will give the capacitance value of the capacitor, but not all of them have this function and it doesn't give the ESR value which may be of significance.

I wouldn't hesitate to replace any capacitors that are domed or leaking as this indicates that they are failing or have failed. Their values are printed on the side of the capacitor itself. Also for some perverse reason with electrolytic capacitors, being polarity dependent, the -ve side of the capacitor is marked on the case of the capacitor and yet the +ve side for the +ve leg of the capacitor is marked on the board that it is mounted on. So take notice of how they are mounted before you take them off and when you go to connect the new one.

Finding a schematic for the amp or a service manual would really go a long way to help you get it going again, but a quick search online found no results. You may have better luck.