Spinet organ tuning (pics included)

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RideTheCrash

RideTheCrash

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I've already contacted someone, but I'm sure they are busy with the Christmas break and all. I own a mid-70s Farfisa spinet organ which is not surprisingly, pretty flat. It's annoying if I want to use it in a recording because I have to tune the guitars to the organ. I've learned how to open the entire thing up and I can point out certain parts (reverb tank, power supply & amp, key contacts, etc).

I've found plenty of examples of tuning coils for combo organs (combo-organ.com) but can find nothing that looks like a tuning coil in this organ, which makes me wonder if I can tune it. I've cleaned out the organ (still have to do key contacts though) and managed to fix two dead lower manual keys. You can see the pics here:

http://s5.photobucket.com/albums/y157/smashguy37/Organ Insides/

Tuning coils (usually) look like a small can with a screw or hex adjustment on the top apparently. I know organs of this nature don't get discussed much around here, but do you guys have any ideas?
 
never worked on a spinet but several of the combos... i suspect the generators are under that cage frame in i think it was pic 2... do not use a metal screwdriver when adjusting this... 2 problems... the coil is magnetic and it will affect the tuning so when you pull back it wont be the same... also there's a good chance of shorting something out if your not reall good with tools... check with local elect shops esp if there's a ham radio place... they may call them diddle sticks... if your way unlucky the generators wont be marked as to pitch and you'll have to figure it out before you start tuning...
 
if you mean the long board you showed no... with out seeing the other side of it i suspect thats the keying diode/logic board... your lookin (mostlikely) for 12 small identicle boards... on the combo stuff they were in a separate card cage accessed from the back... not sure about the spinets...
 
just outta curiousity... is the thing intune with it's self but not at a440??? if so... that would be unusuall... and you may have a master oscillator with a bunch of dived by 2 chips.... you may be looking for a single adjust...
 
Yes, I don't have a chromatic tuner, but the organ is in tune with itself, but it's flat. The entire organ. The back of the circuit board on the pic I last posted is just this: http://s5.photobucket.com/albums/y157/smashguy37/Organ Insides/?action=view&current=organ2.jpg

I think...it's just all the key contacts and stuff. I haven't found anything that is identical and there's 12 of them.

In this pic:
http://s5.photobucket.com/albums/y157/smashguy37/Organ Insides/?action=view&current=organ1.jpg

From left to right at the back it's: the amp, the fuse (I think) and there is a small screw to adjust for volume. There is also a small lightbulb that is probably dead, and I have no idea what it's for. Then we have a small Accutronics reverb tank next to that and then that small little circuit board at the far right, well I have no idea what it is.
 
ok... now we're getting somewher.. where i dont know but anyway... as the thing drifts out the likelyhood that htey drift exactly the same amount in the same direction if it's got 12 generators would please wheelma no end as it would prove the existance of god.... so it's way more probable that what you've got is a system with a master oscillator that then divides it for different frqs... get me??? so look for single controlls... if you dont know what you're turning mark the thing first so you can get it back where it was...
 
RideTheCrash said:
Hmm, sounds very possible. I'll have to open up the organ after the craziness of Christmas passes. Right now I'm eyeing the bottom little circuit board: http://s5.photobucket.com/albums/y157/smashguy37/Organ Insides/?action=view&current=organ6.jpg as a possibility.
Click to expand...
Hi, I've just run this past my father (who has built an organ or two the 70s) and he reckons that that board is the generator. Also, the two silver polystyrene capacitors have probably changed value over the years which likely accounts for the drift. You should probably look at replacing them with close-tolerance mylar capacitors. Don't use ceramics as they will tend to drift as the temperature changes.

Hope that helps,
 
Very cool, thank you. The black circle with the white thing has what looks like an adjustment, so I think I'll mark it where it is and then try moving it and seeing what happens. I've wondered about the caps in this organ, but all appear to be in good shape though I should replace them, it would be a big job that requires outside help.
 
Swain Electronics got back to me and said:

"...Sorry for not replying earlier but the last two weeks before christmas as in previous years were hectic to say the least.
The range of organs to which the balfour belongs does not have 12 oscilators it only has 1.
The way it works is that a high frequency oscilator feeds into an MDD chip ( multi derivative divider ) this chip which in your organ i think is a 54024 or very similar number. This gives out the 12 notes of the top octave which are then divided down in the same way as the older organs.
This means that the entire organ can be tuned with 1 control (the relative tuning between notes is fixed, so that the organ cannot go out of tune but only out of pitch.
After the holliday I will dig out a manual and tell you which panel to go to and which control to alter..."

So you guys were right.
 
Just like to share that I just got the organ perfectly in tune. I got another email and he confirmed what I was looking at pretty much described the tuning area for my kind of organ. I popped open the top of my organ and did a big turn with a small screwdriver and it came out very sharp so by the time I had adjusted backwards so I was in tune, the slot was almost in the same position as it originally had been, so I guess it's very touchy.

Now I'm just glad I don't have to tune my guitars to the organ. Now I should clean the key contacts someday...
 
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