Repair.

Here you will find some notes on repairs of amps and pedals, we hope they may be helpful.

1) Boss pedals. (Flanger, delay) Though most people use the right power supply or a 9v battery sometimes this break down can cause problems, from noise to inop, dead function.

        A 10uf/16v cap located on the bottom left corner becomes leaky. This is in the same circuit with a 9v Zener diode and a standard transistor that is used for switching, the Zener tends to short. If you encounter either check all of the switching diodes around the main processor. These are NTE 519 diodes. Change the cap, zener and any 519's.

2) Line 6 Spider II series. Complaint: Crackle sound, audio fades, can go loud for no reason.

      This was a tough find as it was so intermitant. Tapping, freeze or heat would not recreate the problem. But after numerous tests the problem was found in a ribbon cable marked J1 on the Pro CBA and H1 on the Power supply. The cable is held with hot melt glue, and carries +/- VL, +/-Audio R-L, Mute, mono/stereo detect and Gnd. The cable is pinched at the factory to perice the individual wires, the pinch cut the wire and was shorting on the mute and mono/stereo detect. Care must be taken as this is a double sided CBA. With the use of "Chip Quik" the female jack and male ends where removed from the boards. Instead of replacing the cable with a factory replacement (which could have the same defect) we point to point hand wired new leads in place.

3) Marshall 2000 Dsl100 or any quad tube amp. Complaint: doesn't have the power it use to, saggy.

      As with any quad output, if one tube fails you can still get audio. Just crappy audio. In this case three of the four EL34's where working. They all had filiments lit, but one tube was open completely. Again as I'm sure you have read, when you change your ouput tubes, change the Phase Inverter too. It's only a couple extra bucks, but when the outputs get weak they can start to draw more from one side of the PI than the other. It's like a teeter todder with one big fat dude on one side and skinny guy on the other. Then make sure you have someone who knows how to bias the outputs. Better yet just change all the tubes it will save time and money. Write down the date on the inside of the cab so down the road you can guesstimate how many hours you've put on.

4) SWR Bass combo solid state. Complaint: loud hum when turned on with no input.

       Most people hear hum they think caps. In this case SWR uses 4) 7.5 1watt zener diodes. This power supplies the power for the opamps and 2 of the four had shorted. A 820ohm 5 watt resistor also opened. All other circuits checked good, and normal function was returned.

5) All electronics. Complaint: Won't work when warm, hums, crackels, other.

      90% of the time is a trouble shows up after warm up and goes away once it cools, or you can tap the side or top and the problem goes away or get worse, it's bad solder connections. Defective parts are defect parts, if they fail they are bad and the problem in most cases wont go away. There are some excemptions. Solder expands and contacts with the heating and cooling of the amp. These strains start cracks around component leads. The more current the part carries the more heat, more heat, more stress. Please do not let some greedy tech charge you for new output tubes, new reverb tank or as I have seen a new transformer over some minor solder work. Like I stated the are exceptions to the rule. There are thermal issues that can cause the same troubles, but if you can tap it and it get worse or it goes away it's solder.

More to come.

Please remeber to be safe. If you are in doubt, send it out. there are voltages in all amps that can kill you DEAD. or worse!

If you want to learn about repairing amps, there are some great books around (see "Resourses" at the top of the page), spend some time to learn about electronics and play safe. Remeber "Be careful in there"