Maintenance for arms with detachable headshells

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I've had about nine vintage tonearms with detachable headshells and currently have five of them on my two turntables..
Victor TT-101
I have had some problems with cartridge/headshell combinations on one of my Fidelity Research FR-66S arms on the Raven since I first acquired it nearly five years ago.
The left channel would disappear with certain cartridges in certain headshells and I returned a couple of headshells in the belief that they were the problem..?
Sometimes tightening the bayonet screw on the tonearm against the headshell would restore the left channel and I have lived with this condition until recently when I read on a Forum that the contacts within the tonearm were spring-loaded....!
I stuck a plastic chopstick down the throat of one of my arms and felt the 'spring' pushbacks on the four individual contactors.
Emboldened by this...I sprayed WD40 into the recalcitrant FR-66S and pushed the chopstick against the springs several times and then inserted the FR-7f integral head cartridge which had also recently 'lost' its left channel...
Voila...miraculous recovery..😎🎼❗️
I then adopted the same procedure for all my other vintage tonearms.

Apart from restoring all proper functionality to my headshell/cartridge combinations....the improvement in sound quality was not being imagined.
Clarity, transparency, delicacy and 'power' seemed to have been enhanced.
So for those of you who enjoy the benefits of interchangeable headshell tonearms...whip out the WD40 and a chopstick and free-up those sticking springs 😍
Deoxit is less toxic to use indoors vs WD40, but if deoxit doesn't help, I'd also use WD.
Hey, now that I've learned something today, maybe I'll take the rest of the day off to listen to some tunes. Great advice, Halcro, but you might need to be careful w the WD-40. It can get gummy and also capture dust. I don't have such an arm, but if I did, I would modify your advice and substitute contact cleaner which is very volatile. It might need to be applied more often but I think that the WD-40 could be a problem in the long term.
Thanks Halcro. But doesn't WD-40 leave behind a film? Obviously it helped in your situation but I'd be more inclined to use an electronic switch cleaner.

So I guess I'm with Swampwalker on this.
Mechanical or electrical issue? In such a case a contact cleaner which includes a lubricant should be used since it is essentially a moving contact.

WD-40 would not be my first choice.
Gosh guys...
You've got me worried now..😱
How can I 'undo' the WD40❓
I'd flush it with De-oxit and then forget about it ;-)

Thom @ Galibier

Picture me slapping my forehead with my hand!!!
I have a cartridge that I have intended to send in to Axel for possible repair do to a strange problem. The sound in the left channel just seems to fade in and out from time to time. Not suddenly but sort of a gentle fade.
After reading this thread and having a De-oxit kit, I decided to give this 'no cost' fix a try. I can not get my chin off of the floor. Not only is the problem now non-existent, but the dynamics have also improved. I am in the process of cleaning all the head shell pins as I type this. I do not want to put dirty head shell pins into and against the clean pins in my arm.
Thanks, and I mean this, thanks for the tip.
So simple yet effective!
Best Regards,