fender rhodes suitcase model preamp (LFO ticking)

[birt]

Not really a stompbox but a preamp with an effect. the problem is that the vibrato LFO ticks, even when the vibrato is not switched on you can hear it.
here are the schematics: http://www.fenderrhodes.com/org/manual/ch11.html (it's the first in the list, the second is the lay-out)

the reason i post this here is because i am not really familiar with this LFO and before i start desoldering the MC1458 i'd like to know what other components can cause that ticking. or some kind of explenation of how this LFO works (with the great risk that i really don't get it tough :p)

thanks,
bert

[gez]

Is this built by the manufacturer and has started to tick, or a home build?

[axg20202]

A shot in the dark, but I think it is quite common for people to recap these old preamps to get rid of dried up and leaky caps. I'm not a suitcase owner (I have a stage model), but I hang around the various Rhodes groups.

[analogmike]

Mine did have bad capacitors, got it working pretty well by replacing the dead ones.

Get out your cap meter, good luck!

[R O Tiree]

After changing out all those old electrolytics caps...

If it's still ticking, try changing R8 for something like 1M.

[axg20202]

Hi Birt. Did you manage to get any joy with your preamp?

On the subject of this preamp, and while you've got it open, you could really do me a huge favour here. I'm in the process of reversing this PCB but I'm lacking some of the details which would be obvious if I had some close-up gut shots and/or someone to have a poke around for me. Particularly the model of the LED/LDR photocells and also the details of what all the 'E' numbered pads hook up to. Any chance you could help me out?

Thanks,

Andy.

[birt]

i just got back from a ten day theatre festival (20 days of work for me that is) so i haven't looked at this for quite some time. thanks for the info and i'll let you know when i get to it again

[birt]

i changed the caps and it works perfectly now. thanks!