Solid State Guitar Amp Forum | DIY Guitar Amplifiers

Hello,

I've been doing some research on the best way to drain the voltage from my Ampeg vh140c solid state head. I am fairly new to the amp repair game and would like to know the best(& safest)  way to drain the power supply on this amp specifically. I've grabbed a copy of the schematic here
http://www.eserviceinfo.com/index.php?what=search2&searchstring=Ampeg+VH140C+guit+amp.pdf (http://www.eserviceinfo.com/index.php?what=search2&searchstring=Ampeg+VH140C+guit+amp.pdf)

Am interested to know if this unit has bleed resistors already installed or do I need to make a discharge tool? Also how well does the method of hooking up a guitar and playing it as you disconnect the unit from the power source work?


Thanks in advance for any advice!

You're going to want to check for voltage across the power supply caps with a voltmeter.  If there is any voltage present you will want to drain it.  You can use a large resistor, a light bulb, or a screwdriver (not recommended since it can be potentially really dangerous, though it has been done) across the two leads on the power cap.

**edit**
If this is too vague, let us know.  No point in you getting hurt "just trying" when you don't fully understand.  This can be lethal.

Thanks for the reply, yes I do understand where your going with this. I will be checking cap voltage before I touch any components and will use a large resistor if there is still voltage present.
This being said, I have never actually done something like this myself before, so I wanted to get as much information as I could before opening the unit. Also I'm not that great at reading wiring diagrams so maybe there was something I was missing in the design that would aid in the discharge of voltage.
If you have any other thoughts..any at all, let me know...cant ever have too much info :D

Solder permanently a 4700 ohm resistor, 1 watt , across each capacitor.
It will not affect normal use but will discharge those big caps in a few minutes when off.