E-311 percussion decay problem

[Guest]

Hi there, I have an E-300 series unit which works OK except for a couple problems. One is the percussion does not decay (on a related note, the percussion repeat does not work), the other is that the vibrato does not work. The switches only increase the volume when depressed. I can live with the vibrato, but I would like to get the percussion going.I have had a look a the switches, the percussion/reiteration driver chassis, etc, and can't see any obvious problems.
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I realize that this is kind of a vague question, but does anyone have any tips on how to approach troubleshooting and solving this problem? My electronics skills are moderate - not great, but enough to pull and replace components, etc. </p>

Thanks guys!
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[bluetantra]

Re: E-311 percussion decay problem



Looking at the schematics, I'd first suspect a common 12AX7 tube in both the vibrato and percussion problem since both the vibrato pre-amplifier and percussion pre-amp each use half the same tube, V104. From the rear of the organ, the percussion/pre-amp chassis is located nearer the top of the organ and has 7 tubes mounted horizontally and probably encased in removable metal shields. V104, a 12AX7, is the fourth tube from the right of the chassis. I think I'd also suspect V106, (another 12AX7) the fifth tube from the right on the same chassis, as it's also part of the percussion/reiteration circuit. There are also a couple of 1uf electrolytic capacitors on the percussion/reiteration driver board that could very possibly have failed as well. Hope some of this helps.</P>

[Guest]

Re: E-311 percussion decay problem

Thanks bluetantra. I have tried swapping out the 12AX7s as you describe with a new one. That didn't seem to help. I only tried swapping one out though, maybe swapping both would have more of an effect. As I said, visually the perc/reit driver board (attached to the reiteration pot) appears ok but it could well be dried caps. Maybe it will be worthwhile to get some replacement caps and try subbing them in. I'll let you know when I try that.

[Fenrirlupus]

Re: E-311 percussion decay problem



not sure if the same procedure applies as with the m100, but...</p>

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turn the volume all the way up, place something on the upper manual keys, turn the percussion on, and there should be a little slotted potentiometer thing on the amplifier.  turn this until you can barely hear the percussion (remember, this is at maximum volume)</p>

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says in the manual to do that whenever you swap the preamp tubes for the percussion. </p>

[gientke]

Re: E-311 percussion decay problem

Sounds like a bad capacitor. Test them - there are some large capacitors in precussion unit that will charge very very slowly. They all should show infinite resistance eventually - except the one that is bad.

[Guest]

Re: E-311 percussion decay problem



Thanks guys, I will try both of those things. </p>

I messed around a bit with the vibrato too, but didn't have any luck. In doing so, I discovered the vibrato switch on the expression pedal...interesting. For now, switching the vibrato on only serves to make the volume louder.</p>

I know this might be a dumb question and I could probably google it, but do I have to remove the caps to test them? Yes, there is a large brown cap in the percussion driver board.</p>

Thanks again for your help!
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