Broke the middle pin of the one of my tubes
- Thread starter bermuda_
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stephen sawall
Well-known member
If you are talking about the center post .... that is not a pin. The tube should work fine. Just need to make sure it is lined up right. If you line up the pins and holes wrong you can do damage.
The keyway replacements are excellent. Yet until you get some, take a bottle of white out and use
just a dot on the side of the tube where the key would be, and a dot on the chassis where the key would
line up, then you simply line up the dots. Take your time, if you put it in wrong you may very well ruin the
tube if not more. Try the dot method. Let me know how it works for you.
/cheers
just a dot on the side of the tube where the key would be, and a dot on the chassis where the key would
line up, then you simply line up the dots. Take your time, if you put it in wrong you may very well ruin the
tube if not more. Try the dot method. Let me know how it works for you.
/cheers
212Mavguy
Well-known member
LerxstLee said:
Right on! I used a black sharpie marker on a brown based tube to do the same thing. Think that using the white out is a better way to go by far.
94Tremoverb
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Just to be more complete:
If it's one of the power tubes, mark the position of the keyway on the tube by looking carefully at the broken stump - you should be able to see where it was. If not or you're not sure, most 6L6 and EL34 tubes have pin 6 missing (because it's not used for a connection). The pins are numbered clockwise when looking at the base of the tube, and the keyway is between pins 1 and 8, so if you count two pins clockwise from the missing one (7,8), the keyway is in the next gap. If there are *two* missing pins (some 6L6s are like this) they are pins 1 and 6, so you can still work it out.
Once you've done this and checked where the keyway slot in the tube socket is, fit the tube so it matches. Now turn the amp on *with the standby switch set to standby/mute*. Check that the filament in that tube lights up. If it does, the tube is in correctly since this is the only arrangement that will connect the filament pins to the supply. Now you're good to go. If the filament doesn't light up, *do not* flip the standby switch - you may blow the tube or burn out something in the amp, depending on exactly how the tube is in the socket.
If it's a rectifier tube, you can't do this standby procedure because the tubes are powered up as soon as the amp is on. You *must* make absolutely certain it's in the right way round before you switch on. Luckily on a Dual/Triple Rectifier you have another clue - the grey plate structures inside the glass are oriented in a particular way relative to the pins (at least on tubes from the same manufacturer), so if you look at the other rectifier tubes and make sure that they are all lined up the same, that's a further indication of safety. Rectifier tubes also often have pins 3, 5 and 7 missing which can help identify where the keyway is supposed to be.
If you get it right, there is no reason you need to replace the tube, but be absolutely certain you do know what you're doing - if you get it wrong the first sign is usually smoke coming out of the amp!
If it's one of the power tubes, mark the position of the keyway on the tube by looking carefully at the broken stump - you should be able to see where it was. If not or you're not sure, most 6L6 and EL34 tubes have pin 6 missing (because it's not used for a connection). The pins are numbered clockwise when looking at the base of the tube, and the keyway is between pins 1 and 8, so if you count two pins clockwise from the missing one (7,8), the keyway is in the next gap. If there are *two* missing pins (some 6L6s are like this) they are pins 1 and 6, so you can still work it out.
Once you've done this and checked where the keyway slot in the tube socket is, fit the tube so it matches. Now turn the amp on *with the standby switch set to standby/mute*. Check that the filament in that tube lights up. If it does, the tube is in correctly since this is the only arrangement that will connect the filament pins to the supply. Now you're good to go. If the filament doesn't light up, *do not* flip the standby switch - you may blow the tube or burn out something in the amp, depending on exactly how the tube is in the socket.
If it's a rectifier tube, you can't do this standby procedure because the tubes are powered up as soon as the amp is on. You *must* make absolutely certain it's in the right way round before you switch on. Luckily on a Dual/Triple Rectifier you have another clue - the grey plate structures inside the glass are oriented in a particular way relative to the pins (at least on tubes from the same manufacturer), so if you look at the other rectifier tubes and make sure that they are all lined up the same, that's a further indication of safety. Rectifier tubes also often have pins 3, 5 and 7 missing which can help identify where the keyway is supposed to be.
If you get it right, there is no reason you need to replace the tube, but be absolutely certain you do know what you're doing - if you get it wrong the first sign is usually smoke coming out of the amp!
stephen sawall
Well-known member
I plug a other tube in and make sure I have good light .... so I can see exactly how it fits in. ..... and then use all the advise above.
I have seen this happen to several people. Getting the post out of the amp can sometimes be the biggest project.
As long as the glass is not cracked ..... it should be fine.
Any time you put in tubes it is a good idea to do the start up steps stated in the post above. Watching what the tubes do well being turned on for several minutes.
I have seen this happen to several people. Getting the post out of the amp can sometimes be the biggest project.
As long as the glass is not cracked ..... it should be fine.
Any time you put in tubes it is a good idea to do the start up steps stated in the post above. Watching what the tubes do well being turned on for several minutes.
just for the record, I broke the stump of one of my rectifier :lol: so for not mentioning that earlier, but luckily I had a spare one lying around, so I put that one in instead, but one thing I did notice when I was putting the other rectifier tube in the amp was, it did fit in the amp but for some reason it felt kinda of loose compared to the rest of the tubes in the amp, and not matter how much pressure I had applied on the tube it still doesn't feel fully seated in the amp?
stephen sawall
Well-known member
Did you remove the piece that was broken off from the amp ?
stephen sawall
Well-known member
I never had any problems myself. Breaking off that part of the tube has happened to lots of us. Your other problem with the tube staying in place may be able to be fixed with a tightening of tube sockets.
http://www.thegearpage.net/board/showthread.php?t=427922
http://www.thegearpage.net/board/showthread.php?t=427922
Info below but:
Prevention is the best medicine for this problem. If you feel the need to keep changing your tubes,
and you refuse to gently hold the tube clamps and rotate them very slightly as you pull them, then
leave them alone. Most tube guide pins break for two reasons in my experience.
(1) They have been in and out so many times it weakens them.
(2) The person removing the tube pulls them "straight" out, yet at an angle and pop.
To your question on the tube safety.
Make sure your tube clamps are tight esp on that tube. The guide pin, also adds some stability,
thus I would make sure all your tube clamps are tight,within reason, yet a tube without the guide pin
sometimes may move a bit more during transit. After a few moves if it stays put you should be fine.
There are many ways to add to this conversation, Yet if you find the guide pin, use the white dot theory,
you won't need to let this get very involved. Yet if it were my quad of EL34, metal base mullards, I would
still do the same white out dot. Perhaps order some of the slip on tube keys in case my son decided
he wanted to play at a friends house without asking.
A quick note to add to my white out method. I also have a method I use to get the guide pins out when they
are stuck in the sockets. Some sockets they will fall through, but most recent mesa's they just are hard to reach,
thus my eraser side of the pencil, it really does not matter but I use that side, take some strong tape and make a small
loop, attach it to the part of the pencil that will give you the best angle and press down, Presto I have never NOT been
able to retrieve one, unless it is the socket with a large enough center hole, or the tube guide broke so far from the tube base that less than 1/8th of an inch is in there. I would then find something smaller and still use double sided tape or make a loop of tape as I suggested.
Some older tube amps I have to get into the chassis where they fell.
/cheers
Prevention is the best medicine for this problem. If you feel the need to keep changing your tubes,
and you refuse to gently hold the tube clamps and rotate them very slightly as you pull them, then
leave them alone. Most tube guide pins break for two reasons in my experience.
(1) They have been in and out so many times it weakens them.
(2) The person removing the tube pulls them "straight" out, yet at an angle and pop.
To your question on the tube safety.
Make sure your tube clamps are tight esp on that tube. The guide pin, also adds some stability,
thus I would make sure all your tube clamps are tight,within reason, yet a tube without the guide pin
sometimes may move a bit more during transit. After a few moves if it stays put you should be fine.
There are many ways to add to this conversation, Yet if you find the guide pin, use the white dot theory,
you won't need to let this get very involved. Yet if it were my quad of EL34, metal base mullards, I would
still do the same white out dot. Perhaps order some of the slip on tube keys in case my son decided
he wanted to play at a friends house without asking.
A quick note to add to my white out method. I also have a method I use to get the guide pins out when they
are stuck in the sockets. Some sockets they will fall through, but most recent mesa's they just are hard to reach,
thus my eraser side of the pencil, it really does not matter but I use that side, take some strong tape and make a small
loop, attach it to the part of the pencil that will give you the best angle and press down, Presto I have never NOT been
able to retrieve one, unless it is the socket with a large enough center hole, or the tube guide broke so far from the tube base that less than 1/8th of an inch is in there. I would then find something smaller and still use double sided tape or make a loop of tape as I suggested.
Some older tube amps I have to get into the chassis where they fell.
/cheers
bermuda_ said:
I knew I read some posts by this one. You try to help someone, and I think they might just be baiting.
Perhaps you are trying to get your next level on the board.
Fellow members, look at the help you all have put into this, then look at his posts.
Here is my favorite, tell me is it me, or can someone really want to make themselves this helpfull?
http://forum.grailtone.com/viewtopic.php?f=16&t=41856&p=301517#p301517
I just found another to BLOCK. I fell for it.
Well just for the record, Im inexperienced when it comes to knowing about tubes, so I'm incapable of helping others people out on this board, regardless of how much I would love to help them out, but I'm shocked to see you feel so offended by this, really in all fairness man what do you want me to do?
