Hi Rob ,
The things with the stripes are resistors , and we will check those with an Ohm meter to verify that they are good . Although they can be known to age fail just like caps , It's far less likely . Once all the caps are replaced it's usual practice to bring the amp up to power slowly using a variable transformer usually called a "Variac" , and with a small rated fuse (like 5 Amp max) in series in case of any inadvertent short circuits . The only caps likely to be holding any kind of residual charge would be the electrolytics , but since the ones in the amp are so old they aren't holding anything but a future place in the wastebasket . The new caps , after instalation and first power up , COULD hold enough residual charge for a little zap if ya get across it , that's why we will always discharge the new caps before working under there . All ya do is with the power off and unplugged , take any old piece of jumper wire and put one end solidly on ground (yes , the metal chassis IS circuit ground on your amp . Not on all , but on yours for sure) and then touch the other end of the jumper to the + side of each electrolytic . This will bleed off any residual charge to ground ensuring ya don't get bit .
So , get going on the list of caps and we'll discuss this further then . Also , DON"T go out and buy an expensive , high power handling Bose or some such speaker !!! Realize that this system puts out precious few watts , and will sound plenty loud and clear enough when properly matched to an appropriatly rated speaker . The speaker for this amp should have a working range of approx 20 watts and no greater , since the amp aint gonna be driving any 100 watt speaker
. Remember , this was built in a time of "Quality of sound over quantity" and no small phonograph had the BOOM BOOM BOOM attitude of today's killer megawatt systems . It'll sound good . And clear . Just don't expect your hair blowin in the wind from it , cause that ain't happening ...
04-24-2013, 08:55 PM
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