This time its my 100watt marshall valve state...... the power botton has gone...... dunno if its a simple connector problem or it the bottons just knackered....... i'm too scared to look at it myself incase i further the damage...... any ideas where would be cheap and kind enough to look at it?
A good first test for all amplifiers is to check for continuity across the mains plug pins ( whilst disconnected from wall socket - thankyou for pointing that out Zebulon!! ) from live to neutral. Using a multimeter set to "Low Ohms", it doesn't really matter in this case which way round the meter's leads are, and the amps mains switch on, you should get a few ohms - maybe somewhere between 5 and 50? depending on the amp. This checks the mains plug connections, plug fuse, mains lead, internal mains fuse, on/off switch, voltage selector, power transformer primary windings and all connections, all in one go. If the meter doesn't read, one of those items in probably faulty. If a fuse has gone, just replacing it will probably not get your amp going - as 99/100 fuses go for a reason. DO NOT SHORT OUT FUSES WITH SILVER PAPER! Do not open your amplifier! There are some very nasty voltages in there, and the amp can store them for quite some time after it's switched off. Unless you know the proceedures to "disarm" it, they can be fatal!
Tony Edited by: rahamilton at: 4/10/03 10:44 am
This may sound stupid, but make sure your amp is not plugged into the mains while you're doing the checks above!
An acquaintance of mine attempted a similar check by wedging the pins of the + and - testers into the power socket, while the amp was plugged in and switched on....with "hilarious" results.
Hilarious and painful.
Wow! Thats' unbelievable - and very difficult to arrange! Just the sort of person who shouldn't even have access to a multimeter.
He was the sort of person who follows instructions literally, one step at a time, rather than reading them through first...