Cannot unscrew Boss cover

pogul

I have an old PH-2 Super Phaser that works fine on a 9v battery but is completely dead with an AC adapter. I think the power socket is all corroded and horrible, but I can't get the pedal open to investigate further. It should be easy to fix one way or another, but the screws feel welded shut! I've tried a couple of squirts of WD-40 (actually GT-85, but I think it's essentially the same stuff) but that hasn't helped.

I'm worried I'll strip the heads of the screws if I use any more force than I've tried.

Any ideas for getting in to an old pedal without ruining it?

Thanks!

Danny1969

Have you tried a whack with a hammer on the screwdriver - preferably a metal topped one, the impact will loosen the tightness of the thread. Try a few sharp whacks and then turn with a good fitting driver 

ICBM

Boss pedals that have never been opened do frequently need quite a lot of force to break the grip.

Use a large screwdriver that fits the screw heads properly, put the pedal upside down on a bench, and apply most of your weight to the screwdriver before you try to turn it - that will stop it slipping.

But before you do that, have you tried it with a 12V power supply? Older PH-2s take the ACA power supply, and it might not work well on a 9V one... although I think it should at least power up and pass signal, so it's *probably* not that.

If it works on the battery the only other possibility is that the centre pin is corroded (probably at the rivet joint on the back of it) or the wire has come adrift - the positive connection from the battery goes via the switch contacts so they must be fine.

pogul

@Danny1969 -- that got one out! Thanks for the pointer, the other three are still stuck firm. It's almost like the pedals don't like beer and sweat!?

@ICBM -- I feel like a right idiot now! It DOES power up with 12v. I could have sworn I used 9v back in the day, but my memory is obviously flawed!

Thanks for the advice both of you, such a great forum!

ICBM

pogul said:

@ICBM -- I feel like a right idiot now! It DOES power up with 12v. I could have sworn I used 9v back in the day, but my memory is obviously flawed!

You may have used a Boss ACA supply, which is labelled 9V but is actually 12... for slightly complicated reasons! Basically they put a crude regulator circuit in the pedal to drop it to 9V, rather than having the regulator in the power supply. The later PSA power supply is a proper regulated 9V, so they then stopped making the pedals like that.

Assuming you can actually get it apart, you can easily modify it for a modern 9V supply by bypassing the diode and resistor which comprise the regulator - you don't need to remove any components so it can be put back to stock at any time if necessary.

pogul

ICBM said:

Assuming you can actually get it apart, you can easily modify it for a modern 9V supply by bypassing the diode and resistor which comprise the regulator - you don't need to remove any components so it can be put back to stock at any time if necessary.

That's a top tip! Thanks again. Now back to the swishy/swooshing noises!

John_A

You can use older bass pedals with a regular 9v supply as long as they are on a daisy chain with other pedals.  I do like my PH-2

DiscoStu

Another thing to do with seized screws - and this goes for anything, not just pedals - is to try to TIGHTEN the screw first to break its 'seal' before unscrewing it.

Jimbro66

Try some heat on the screws. It can’t be any sort of naked flame because of the rubber base pad but you could use the sort of higher wattage soldering iron with a large-ish tip that you might use for example to solder to a chassis. Apply plenty of heat to a screw then use Danny1969’s method applying several sharp taps, preferably with a lighter cross-pein pin hammer to avoid damaging the pedal. Let the screw cool. Do as ICBM said and put your weight on the screwdriver with the pedal lying upside down, making sure the screwdriver is a very tight fit. If that fails repeat the procedure several times.

I have managed to remove seized steel machine screws from corroded aluminium in that way. I’ve not found WD40 type products very effective in that situation to be honest.

Hopefully the machine screws used by Boss are not the Chinese cheese type