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View Full Version : Did I F-up ....? Bridge problems



soundbee
07-05-2012, 09:29 PM
So I'm new to PRSs, but certainly not to guitar and maintenance. "back in the day" I even worked as a luthier and repair man - so I've done my fair share of setups on strats, gibby's, floyd-type guitars, etc... But never on a PRS. Fast forward to now and I've been enjoying my own very first CU24 for about 2 months and decided to do a bit of setup. Well the high e string seemed a tad high and the was as far down as the height screws allowed (saddle resting on the bridge plate). So I did the logical thing and lowered the bridge via the 6 screws. I "only" went 1/2 turn (on all six) and then backed up about 1/4 turn. Now of course I never rtfm'd - where it clearly states that one should never adjust those screws while there's tension on the bridge lest you dull the knife edge. Now it seems I've got a slight bit of tuning problems and cant really tell if it's because my bonehead move or a result of one ore more of the following....

1) tuning to Eb
2) switching to 9 gauge strings
3) using a different brand strings (D'Adarrio - used for 25 years)
4) generally wonkiness with floating trems

I've dealt with bridge related "edge" tuning problems. These can usually be identified by tuning to pitch and then gently depressing the bar / check pitch and then gently pulling up on the bar / check pitch = if there's no fluctuation then it's usually not bridge related. My problem seems to be that I play for a few moments and then check tuning and one or more strings is out. Also, it doesn't seem consistent as to any particular string...

Any suggestions?

Thanks
Kevin

aPeRSon
07-06-2012, 04:02 AM
I had a similar issue with my Cu22 and after a lot of research on the old Birds and Moons website, I found a post that was really useful for resolving this issue. The first thing I'd do is look at the bridge from the back (sighting down the neck) and check that it is sitting parallel with the body surface - if not, take some measurements and a note of how far out it is. Then remove the strings and unhook the tremelo springs from the claw - this will allow the bridge to come off the six screws and sit flat on the body, making measurement of the six screw heights much easier. You should be able to sight along the six screws and see if any are sitting slightly high or low - adjust these now, whilst the bridge is out of the way. You want all the screw slots that the tremelo block pivots on to be perfectly in line and parallel with the guitar top - check in both directions (low E to high E and high E to low E - you may need to remove the volume knob to get a clear view from high E to low E) and if you're as OCD as I am, use a small engineer's rule to make sure they're all at the same height. Whilst you're there, you can also add a (tiny) drop of machine oil to the six screw slots, so that they're nicely lubricated.

Then you can reconnect the trem springs, fit new strings and tune up. The six screws will be pretty well lined up, but the final (micro) adjustment needs to be made with the guitar at normal pitch. Starting with the low E, detune the string and put a screwdriver on the screw just in front of the saddle (detuning the string will allow you to get the screwdriver on there properly). This last adjustment needs to made very carefully, so that you don't mess up the knife edges. Turn the screw clockwise no more than an eighth of a turn, then back to where it was, then anticlockwise no more than an eighth of a turn - you will find that there is a certain point in that travel where the screw turns with much lower resistance - this is the perfect height for that particular tremelo screw. Tune the string back up to pitch and repeat the same process for the next five screws.

I've performed this procedure on both my guitars and they hold pitch just fine now. One last thing that may help too is to lubricate the nut, just in case you've got any binding there.

Good luck and let me know how you get on!

swede71
07-06-2012, 05:52 AM
I start with screws 1 and 6.Strings off,springs off and 2 stacked feeler gauges(0.062)as a guide to get started.When it looks ok,top-plate not tilted,i put on springs and strings and tune up to pitch.Now check with a ruler that
bridge floats perpendicular to and about 1/16th off the body.Make adjustments with strings tuned to pitch and when everything looks good,detune and take off springs again.Have bridgeplate flat to the body and continue with screws 2-5(1-6,treble to bass).My best advice for having the knife-edges lined up properly and this is crucial,sight from the side,bass to treble when you do this,that way you can see the knife-edges as a dark line and in this case it should be a perfect straight line.Springs on again and fit the plate in the knife-edges and tune up to pitch.Now you should be in tune for a lifetime :).

soundbee
07-06-2012, 05:54 PM
Thanks for the tips guys! I'm away from home for the w/e but will jump into it when I get back and let you know the results...

dantedayjob
07-06-2012, 06:28 PM
So I'm new to PRSs, but certainly not to guitar and maintenance. "back in the day" I even worked as a luthier and repair man - so I've done my fair share of setups on strats, gibby's, floyd-type guitars, etc... But never on a PRS. Fast forward to now and I've been enjoying my own very first CU24 for about 2 months and decided to do a bit of setup. Well the high e string seemed a tad high and the was as far down as the height screws allowed (saddle resting on the bridge plate). So I did the logical thing and lowered the bridge via the 6 screws. I "only" went 1/2 turn (on all six) and then backed up about 1/4 turn. Now of course I never rtfm'd - where it clearly states that one should never adjust those screws while there's tension on the bridge lest you dull the knife edge. Now it seems I've got a slight bit of tuning problems and cant really tell if it's because my bonehead move or a result of one ore more of the following....

1) tuning to Eb
2) switching to 9 gauge strings
3) using a different brand strings (D'Adarrio - used for 25 years)
4) generally wonkiness with floating trems

I've dealt with bridge related "edge" tuning problems. These can usually be identified by tuning to pitch and then gently depressing the bar / check pitch and then gently pulling up on the bar / check pitch = if there's no fluctuation then it's usually not bridge related. My problem seems to be that I play for a few moments and then check tuning and one or more strings is out. Also, it doesn't seem consistent as to any particular string...

Any suggestions?

Thanks
Kevin

Kevin, I seriously doubt you did any damage to your bridge... you maybe aren't SUPPOSED to do what you did, but I have done it to every single trem equipped PRS I have owned (10?) and have had a grand total of zero problems as a result. My guess would be a combination of the things you mentioned... so, adjust your trem springs, etc all that you would do in a proper set up and chances are you should be fine.