I need to open my Philicorda GM 754 to clean the key contacts. Some of the keys only sound intermittently, and you need to press them quite hard. So I guess it's dirty contacts. The thing is, I have already tried contact cleaner.
I unscrewed the 3 bolts underneath, but the keybed won't come out. There's qyuite a maze of electronics in there, I can't see how to get access to under the keys.
Does anyone know? There's nothing about this on the internet, at least I can't find anything
you have to remove the legs, then unscrew all the bolts under (there's some big board for the whole electronics, and one smaller board only for the keys but I think it's impossible to remove just one), then you have to try to open it slowly while it's standing on the side... but you gotta be very careful... I don't think that it's possible to remove the top completely... so you have to work on it while the thing is half open...
now DO EVERYTHING you gotta do in one time, hoping you won't have to get back into it later...
Last Edit: Mar 30, 2011 15:46:46 GMT -5 by mtwallet
thanks for the advice, much appreciated. I have it in my band rehearsal room at the moment, it's 15 minutes from home. I might try and fix it tomorrow, if I have any luck fixing it i'll post a report in case others have the same problem
Thanks for the updated advice. However it's too late! I completed the job this evening. Exactly as you said, it was very difficult getting access to the bits under the keys. In case anyone else needs to know, here's how to do it.
As well as the 3 screws underneath, there are a few screws inside, and 1 on the right side once you have removed the sides. You still can't remove the keybed, but it allows it to move just enough so you can poke around a bit.
The sides are held in place by a dowel rod and a metal springy clip; both sides come off and go on again very easily . With the sides off you can just about see under the keys, at least at the end of the keyboard. Each key has a thin rigid wire that makes the electrical contact which makes the sound (you can poke it downwards while the organ is on check it's working - I used a broken drumstick).
The 2 or 3 keys that weren't working properly just needed the thin wire to be bent ever so slightly downwards so it made a better contact. To do this, I had to gently pull the keys out of position by pulling them out and up (it's a bit like dislocating a finger out of its socket). I did this with every key so I could have a look under each key.
Then I used electrical ontact spray to clear up the slight crackling when sliding the volume and reverb controllers.
Finally, under each key there is a small round rubber tips on a piece of upright metal. I can't explain it very well as I don't know what it's called. This gives the key action a soft bouncy feel. One of the rubber bits was missing, and consequently it was slightly out of position (a bit too high) and felt a bit loose compared to the other keys. I had nothing with me I could use to adequately replace it, so I improvised and stuck half a cigarette filter onto it. You can't tell the difference!
So, it all works perfectly now, i'm very pleased. It wasn't too difficult, but it was very fiddly, so it took a few hours. Thanks for the advice, it helped me get on and do the job rather than leave it sitting around unfinished for weeks.
Post by juustomestari on Apr 13, 2011 14:21:19 GMT -5
I am still waiting for my GM754, as my brother was kind enough to make the purchase for me. I am a bit annoyed by some people telling others to avoid the all transistor type. If you want the warm 60's sound, you of course want GM753 or older. But that doesn't mean that the GM754 is "worse", just different. By all the samples I've heard, the cleaner sound appears quite good and useful.
I've heard that the spring reverb should be screwed so it can't move during transit. I wish I had known it before my brother drove around with the Philicorda in his trunk...
i read about screwing in the spring reverb too, and like you only after i'd driven it for 3 hours in the back of my car.
it still works fine so don't worry. In fact I was very rough with it both in transporting and in the cleaning process and I didn't manage to damage anything. The reverb unit wobbles on the spring quite a bit so just make sure nothing falls out of position.
As for the sound, anything tube/valve will be revered by the "analogue warmth" crowd. If this bothers you then I recommend putting it through a nice tube amp and hey presto, that will stop the pregnant doging. ;D
Post by juustomestari on Apr 14, 2011 0:50:49 GMT -5
Definitely nice to hear that the reverb isn't that fragile. By the way, in a Finnish auction site a Philicorda AG7500 is being sold, no photos available. The seller says it "has no tubes, some of these early Philicordas have tubes, this one hasn't", and "you can play it through the loudspeakers inside the case". This sounds a bit weird, especially if "the case" doesn't mean the separate amp unit? I thought all AG7500 organs had at least some tubes?
FWIW Portishead list the GM754 as part of their kit list, and from the photo I saw it's the same one as I have. It's the later model the one with sliding controls for the volume, reverb and vibrato. I also heard that it sounds great with a wahwah pedal, i'll probably try that next week.
It's a converter plug for the 5-pin DIN socket underneath, to allow a more usual stereo jack plug to fit in. The GM754 (at least my version) only has DIN plugs for audio in and out. I just bought one and can confirm it works.
By the way, if anyone wonders why there is an audio in, it' was included so you can play along to record backing tracks through the built-in speaker!
very few philis have tubes the first model AG7500/GM751 exists with AND w/o tubes
So the seller was right all along, and I've been suspicious & moaning for nothing! Well, live and learn. I wonder what changes made the GM754 so different, non-germanium transistors perhaps? I try not to defend the organ too fiercely before actually getting it.
The combination of vintage electric organ and wah-wah is huge fun. I tried it with Eko Tiger and that was just about all the pleasure I had with that dreadful piece of junk.