organ vibrato

Started by 9 volts, February 09, 2007, 04:54:02 AM

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9 volts

Hey there, I'm in the process of trying to fix the vibrato on my portable italian organ. It's a very basic model. When I push the vibrato button it just drops the tone some micro tones but not oscillation. The button seems to be connected to a 1448 ic. I  can't find a schematic and am wondering if anyone can give some guidence or point me to a website etc. (I'm in the process of tryinh to fix my broken gear). It's made by baleani and makes a farfisa look fancy but sounds pretty cool.

ps I have trouble connecting to this new server at times

doug deeper

hey!
figure out were the vibrato board is and replace all of the electo caps.
thats the problem 99% of the time.
my jaguar was a half step sharp and the vibrato did work when i got it. three caps later its in tune and has vibrato.
good luck!

doug deeper

oh! and check out combo-organ.com
also do you have any pics if this? i loooooooooooooooooooove combo organs!
;D

Meanderthal

 Whatcha got there, Farfisa?
I am not responsible for your imagination.


9 volts

I've changed all the electro caps, maybe there is a broken track. I'm going to try to trace the circuit out alittle.
Got a soft spot for those auto chords. (ha)

9 volts

I've noticed that when it is powered up for the first time of the day the vibrato works for a few seconds, after that it doesn't work and if I turn it off and on it doesn't work, until the following day. Could a smaller cap (non electro ) cause this?

doug deeper

yeah its most likely a cap.

Paul Perry (Frostwave)

+1 for Doug. I expect a cap is leaky & screws up the bias on a transistor & stops the oscillation.

9 volts

We're rocking! It was a faulty capacitor. Since then I've looked around alittle with my audio probe and noticed maybe some of the drum sounds are suffering from the same problem (saturated transistors). So there will be a little more work done on it. Man these old pcb's are fragile, I'm going to have to maybe add some glue or something to some of the tracks when I'm finnisehed.
Thanks again for the words of wisdom, I was about to put it back on the back burner!

Paul Perry (Frostwave)

It's pretty difficult to patch up a lifted or damaged track.
I suggest bypassing the track, just run wires (I recommend single strand solid wire) between the points that the track connected.

Sir H C

I love this place, a title like organ vibrato and no base comments.

I have a Farfisa Fast 5 that I am trying to get working, all the dividers are messed up.


doug deeper

yeah the dividers can be a headache.
my latest old keyboard trouble is that i have to tune a wurli replacement tab (it requires filing solder off of the end  :( )
im bound to mess it up.

Sir H C

Ouch!  That is a tricky one.

gez

Quote from: Sir H C on February 12, 2007, 04:03:54 PM
I love this place, a title like organ vibrato and no base comments.


I need to go down the pub more, this didn't even occur to me.  I've been doing electronics too long!!
"They always say there's nothing new under the sun.  I think that that's a big copout..."  Wayne Shorter