Leslie 122 Distortion

[Brent Watkins]

OK, once the amp is out, how exactly do I test the capacitor? I know there are four different plugs, do I need to check each one?

BW

[tonewheel1966]

I would replace the can anyway as a matter of "preventitive maintenance" given that they were only expected to last 25 years max. If you google Tonewheel General Hospital they can supply the can or even a complete kit to recap the whole amp. I did this on my 122 because it was one of the first made and although it sounded okay I didn't want it to go down on a Saturday night when I had just started to play. From what I had read those cans can make a mess if they blow.

Cheers

Dave

[geoelectro]

What I do is this. I turn the amp over while keeping it connected. I measure the AC value on each stage of the filter cap. The first stage will have 7 to 10 Vac. (normal) The second one should be less that a volt. Typically .1Vac. Same for the rest. In many cases, you can measure the DC voltage and make a determination but with the wild variations in local power voltages those readings can mislead.

The second step I do is to play a medium level chord on the organ while monitoring the second stage at .1 Vac. If that voltage rises quickly and gets near or over 1Vac, that stage is bad.

You don't have to replace the whole can. You can install an additional cap under the hood for the bad stage only. There was a time when cans were next to impossible to find and we did that all the time. In some cases replacing all four stages with under the hood caps. New Leslies are stock with four under the hood caps these days. Now cans are easy to get and way easier to replace since most of them just plug in.

ATTENTION! There are very high voltages on this filter cap! 450Vdc will hurt you big time! I know. I do it all the time!! []

Geoelectrro

[Sphiwe]

Hi

I know its three years later.

I also had the same problem, all to find out that it was the cross-over.

Thanks

[Sweet Pete]

Besides the can cap in your 122,the caps in your 122 x-over have probably drifted off their ideal values.Rebuilding the x-over and recapping the amp will make a huge difference.
If your A100 sounds as good through it's internal amps as mine does......check your 122.
The can caps have markings to identify which tab you'll break off to mount it.Look for the semi-circle,triangle,and square.......note which way the old can was oriented when you remove it.