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Church and H.O.W. – Forums for HOW Sound and AV - Your Displayed Name Must Be Your Real Full Name To Post In The Church and HOW Forums => Church Sound => Topic started by: Ken Webster on June 25, 2018, 07:43:50 PM
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OK, so it's time to lube the console controls again. A can of F5 with postage is about $50 AUD minimum and the tube it comes with is just incapable of efficiently delivering lube into the pots. I attach a 1.2 mm dia hypodermic needle to the cans plastic tube. This is much better, but the needle is still too large to inject lube directly into small pots. A lot, perhaps most of the lube is still wasted. Has anyone come up with a good system for doing this, please tell?
Oh yeh, the needle came from a pile of stable manure I got for the garden.......
Ken
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Silence Hmm, not sure what to make of that?
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OK, so it's time to lube the console controls again. A can of F5 with postage is about $50 AUD minimum and the tube it comes with is just incapable of efficiently delivering lube into the pots. I attach a 1.2 mm dia hypodermic needle to the cans plastic tube. This is much better, but the needle is still too large to inject lube directly into small pots. A lot, perhaps most of the lube is still wasted. Has anyone come up with a good system for doing this, please tell?
Oh yeh, the needle came from a pile of stable manure I got for the garden.......
Ken
What kind of console. Most of them will be damaged if you use the wrong stuff. What does the manufacturer recommend and why do you think it needs to be lubed?
Usually by the time a potentiometer has gotten to the point where you are hearing a problem when it is moved it is on its last legs. In other words they are damaged to the point that the lube is just a band aid. They are on their way out.
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Spraying the lube around a the shaft on a pot will not do much. Some pots have openings where you can get a few drips of lube actually on to the conductive surface other pots are sealed.
Sometimes it helps, sometimes not for long, sometimes not at all.
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I'm with the other guys here. Maybe on the faders but follow the manufacturer recommendations there. If a pot is scratchy replace it, you should be able to do this yourself.
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What kind of console. Most of them will be damaged if you use the wrong stuff. What does the manufacturer recommend and why do you think it needs to be lubed?
Usually by the time a potentiometer has gotten to the point where you are hearing a problem when it is moved it is on its last legs. In other words they are damaged to the point that the lube is just a band aid. They are on their way out.
Yes, agreed but no funding available so I have to do what I can. All fader and pot tracks are carbon in the Yamaha MR series. Using Deoxit F5 spray as it makes the controls feel smooth and I read it's compatible with pretty much all resistance track types. Some of the pots get a bit scratchy sounding and stiff. I got a smaller desk in the series for parts. Had 2 faders go open circuit and swapped them out. A midrange EQ pot isn't working currently but resistance tests as OK so I'll replace the channel board for that one. I tend to agree the console is on it's way out but do what I can anyway.
I think I may have a better way of getting the lube into the pots now. I warmed up a cotton bud tube and stretched it out to a make a thin tube, enough to get into the pots, can even put a bend in it. I think I can add this as a tip to the can's existing tube and just spray the lube directly into the pots. Been doing this sort of thing on vintage stereo for years, seems to keep them going for decades. I did about half the board on what remained in the previous can. So I'll try these tips on the rest and see how it goes. Basically all the controls have become stiffer than they should be so probably not far from giving trouble so may as well get lube into all of them.
I just thought there must already be small tube tips available to solve this but haven't found any yet.
Ken
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Yes, agreed but no funding available so I have to do what I can. All fader and pot tracks are carbon in the Yamaha MR series. Using Deoxit F5 spray as it makes the controls feel smooth and I read it's compatible with pretty much all resistance track types. Some of the pots get a bit scratchy sounding and stiff. I got a smaller desk in the series for parts. Had 2 faders go open circuit and swapped them out. A midrange EQ pot isn't working currently but resistance tests as OK so I'll replace the channel board for that one. I tend to agree the console is on it's way out but do what I can anyway.
I think I may have a better way of getting the lube into the pots now. I warmed up a cotton bud tube and stretched it out to a make a thin tube, enough to get into the pots, can even put a bend in it. I think I can add this as a tip to the can's existing tube and just spray the lube directly into the pots. Been doing this sort of thing on vintage stereo for years, seems to keep them going for decades. I did about half the board on what remained in the previous can. So I'll try these tips on the rest and see how it goes. Basically all the controls have become stiffer than they should be so probably not far from giving trouble so may as well get lube into all of them.
I just thought there must already be small tube tips available to solve this but haven't found any yet.
Ken
It sounds like you know what you are doing. The one thing to keep in mind is that in a forum a lot of people read them and there may be some that read and don’t have your experience. They may try things thinking that they can spray stuff in places that they never should. So it is a good idea to warn the general public to be careful. Good luck with your mixer.
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It sounds like you know what you are doing. The one thing to keep in mind is that in a forum a lot of people read them and there may be some that read and don’t have your experience. They may try things thinking that they can spray stuff in places that they never should. So it is a good idea to warn the general public to be careful. Good luck with your mixer.
Ta and point taken.
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Oh yeh, the needle came from a pile of stable manure I got for the garden.......
Ken
Stop injecting horse shit into your MR. It sounds bad enough already.....
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Stop injecting horse shit into your MR. It sounds bad enough already.....
Oh, I'm hoping it will come into full bloom! ;)
I finished the lube today. Removed the board with the failed mid tone EQ. Pots are OK so suspect a chip. Took the good fader off this board and replaced an open circuit one on an otherwise good board. Swapped the now good board back into the console. Tightened a loose earth that I suspect was causing some noise on the monitor system. Checked every control function on every input channel and the main ST and 3 AUX out functions. All good!! Didn't bother checking RTNs as we don't use them. So it's all functional except 2 sticky VU meters. one of which has a driver fault on one of it's dual functions. No fault on the signal though, just the driver. While it would be nice to fix these metering issues, I have to get the console in service again ready for tomorrow.
Maybe another time I can do the meters but I am reluctant to swap a meter driver chip from one board to another, a lot of risk of cooking the chip.... Maybe I'll just disable the function switch so it stays on the setting that works. If I don't fix the chip or disable the switch, someone will flick the switch which will pin the needle over hard and kill the meter again. Sigh!
So off the install the mixer, check levels and EQ with a new dBC meter, Oh what fun!
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Sometimes scratchy pots are just that, worn out pots.
Another cause for scratchy pots is not so much the fault of the pot but the circuit associated with the pot has DC voltage leaking across the pot.
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Sometimes scratchy pots are just that, worn out pots.
Another cause for scratchy pots is not so much the fault of the pot but the circuit associated with the pot has DC voltage leaking across the pot.
Hmm, I did find some loose earthing and suspect that related to poor sound within the monitoring system, the main and AUX outs sounded clean except when adjusting 3 or so specific pots. The metal chassis is not grounded to its own supply. In case you're wondering, the power plug is 3 pin and the lead is a flat 2 core (active & neutral only). There is no evidence of tampering and the smaller mixer I bought for parts has exactly same hardware and setup so this all appears to be original. The service manual clearly shows the US and Canadian models are grounded to the supply but the European model (with a voltage selection switch) is not grounded to the supply.
I reckon most electricians here in Australia would be shocked by this.....
Ken
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The service manual clearly shows the US and Canadian models are grounded to the supply but the European model (with a voltage selection switch) is not grounded to the supply.
I reckon most electricians here in Australia would be shocked by this.....
Ken
Great name by the way.
I wonder if that's related to us having half the line voltage you deal with down under.
Panel meters are often a weak link. You might consider a digital replacement. It could be an interesting project, particularly considering you have an old mixer to play with. Cheap online parts may be available depending on what you actually need.
Ken
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Great name by the way.
I wonder if that's related to us having half the line voltage you deal with down under.
Panel meters are often a weak link. You might consider a digital replacement. It could be an interesting project, particularly considering you have an old mixer to play with. Cheap online parts may be available depending on what you actually need.
Ken
I Don't believe so, over time Australian consumer voltage standard has changed slightly but has always around 240 VAC. This is significantly dangerous of course and it is very highly unusual for a metal chassis device to not be earthed here. Yamaha appears to be an exception, at least sometimes anyway. Suspect it may be to avoid the possibility of ground loop hum. I just hope that PSU is extremely well insulated, hard to see though.
Ken