Fragile cart slot?

[TylerL]

I recently received an original-style Famicom from eBay (GPM-02).
Very yellowed (and filthy!), but still has all its stickers, and even has the original plastic film over the front label!   

One thing I noticed during initial testing, and which didn't go away after a thorough internal/external cleaning of both carts and system, is the apparent fragility of the cart slot.

When fully inserting a cart into the slot, I'm greeted with a black screen upon power-on 99% of the time. The other 1% is garbled graphics.
If I lift the cart up a millimeter or two, my picture is FLAWLESS. All games play perfectly.
But, at the slightest touch of the cart, graphics become distorted, if games don't outright crash.

Is this a common?
What could I do to strengthen the slot-to-cart connection? I already have a replacement cart slot (among other parts) en-route, but that seems a bit overkill, especially considering I've never done soldering of such a scale (and with tiny crowded pins)...
Or, could the metal shielding around the cart slot on GPM model boards be somehow shorting pins? Grasping at straws until I can get another closer look...

Thanks!
Post Merge: February 06, 2013, 02:40:55 pm
Update!
Got home and tried some more. Got a very close look at the cart slot. The shielding and pins all looked uniform.

So, I tried another slot cleaning technique:
1: Clean a cart's pins AGAIN. Until Q-Tips come out sparkling.
2: Douse the cart pins in alcohol by rubbing a couple oversaturated Q-Tips on both sides.
3: Repeatedly insert the cart into the slot and pull it out.
4: Repeat steps 1-3 again for good measure

Done! I now have absolutely no problem inserting a cart normally and playing. I can bounce a cart around while the system is on with no ill effects.
Next up: Retr0brighting, AV modding, (and playing) while I wait for my N8 EverDrive 
Post Merge: February 07, 2013, 05:22:36 am
Update 2: Spoke too soon!
While I had no trouble at all with two carts, a Super Mario Bros. 3 cart brought the system back to the way it was before. Even the first two carts (that I could fully insert and bat around while powered on) need the same slight lift and paranoia again...

Am I simply not cleaning the cart/slot contacts correctly? Is there something else I should be trying?

[aha2940]

I had a very similar issue with my famiclone, it would show garbled graphics on start, needing constant cleaning of the cartridges, blowing them and constantly got distorted graphics if the console got moved even a bit while turned on. It's an early-90s famiclone, and disassembling it shows the board being a chip-by-chip clone of the original famicom. The case is even a clone of the original famicom (minus the eject mechanism). Now, I solved the problem replacing the PPU. I got a PPU from a burned NES board, got it desoldered (I have no soldering iron, smebody used a heat gun to do the job for me) and installed it on my famiclone (CPU and PPU are socketed, so it's really easy to replace them). Now, my famiclone works always, no need to wiggle the cartridges or anything. I know this has little sense, but it worked for me.

Regards.

[TylerL]

After another run of rough slot cleaning (douse cart contacts with 99% alcohol, insert/remove/rock repeatedly) with my trouble cart (SMB3), I'm back in business and not worried about killing my game by accidentally bopping the system. Relieved I don't have to make any drastic hardware replacements (yet...)   

[tonev]

This is funny because smb3 also did the same to one of my famicom systems Maybe it is some kind of bad luck with smb3 carts  but cleaning it did the job (maybe inserting dirty carts can cause the problem but i always clean carts when i get them from someone else or if i haven't played them for a while)