RETUBED PHANTOM ARCING

[Sonar]

After retubing my phantom everything worked fine. The tubes seemed to be healthier than the one's I removed (original d&a 6lq6's)
I used it twice since re tubing it and even left the amp powered on for several hours the first day.
It hasn't been used since last Thursday. I turned it on today. Let it warm up for the usual 10 minutes then called to a local. After the fourth key down the amp arced. The radio room is dark and I saw a bright blueish arc. The amps power light flickered and dimmed as did a single light bulb that's plugged in a different outlet from the amp (station.)
I only noticed after looking at the photos I took of the install that one 6lq6 was not in straight and almost leaning on another. I'll add the picture. Could this tube be close enough to cause this arc? Should i put the old 6lq6's back in if the tube that's leaning a bit wouldn't cause an arc? It never arced with the original tubes. Should I just remove the cover and push the tube in its socket properly? I probably shouldn't have but after eating I turned the amp on again and keyed then modulated and no arc.
Can y'all advise me. Thanks. Happy Thanksgiving.

 

[543_Dallas]

I don't think the leaning tube is going to cause an arc but I would still correct it and retest. I see some dark spots on the leaning tube on the right. Are these replacement tubes taller and arcing against the top cover?

If it still happens and all you've changed is the tubes I'd suspect one of them is shorting out. Try a known good spare and swap them out one at a time to see of the problem goes away. Inspect the anode connections at the tops of the tubes for cracked solder joints, broken wires or resistors.

 

[Robb]

Think I wouod watch it closely and try again - to be certain where it is happenig.
Pretty hard to start any troubleshooting with few facts . . .

 

[BJ radionut]

Looks like couple issues...those choke resistors most certainly have changed value...which may cause issues with tuning(also can cause amp to get dirty)Suggest replacing...One or more I noted may be cracked which easily may cause an arc to accrue (remember that is the High Voltage passing through those)...
That tube noted maybe OK...however could have also flashed over inside due to a short...would suggest replacing that one until it's tested properly.
GL
All the Best
Gary

 

[Sonar]

I don't think the leaning tube is going to cause an arc but I would still correct it and retest. I see some dark spots on the leaning tube on the right. Are these replacement tubes taller and arcing against the top cover?

If it still happens and all you've changed is the tubes I'd suspect one of them is shorting out. Try a known good spare and swap them out one at a time to see of the problem goes away. Inspect the anode connections at the tops of the tubes for cracked solder joints, broken wires or resistors.

Thanks for responding. The tubes are all exact in height. I think I'm going to send all the tubes for testing.
I have the nine original 6lq6's and ten I purchased as replacements.
I have a total of 19 and I think (hope) I could get nine between all of them that test good enough for full output. And hopefully long lasting.
Someone actually posted that he liked the look of the original d&a's as opposed to the replacements.
As I mentioned in my op this arcing never happened with the original tubes.
Thanks again. 73. Picture no 1 original tubes.picture no.2 replacements

 

[222DBFL]

One thing I see that I don't know if it matters or not is that there is an insulated white bolt with a nut on top. First photo it appears the wiring is much shorter and in the 1st pic it appears that only one wire is going down to this bolt/nut setup. In the 2nd photo it appears as if the wiring has been shortened and that the resistors are much closer to this bolt than before. I zoomed in on the part I speak of and took photos.
Let me say as well, I am far from being any type of amp expert or claim to know much if anything about tubes amps!! I don't like AC power. Especially HV stuff. Please keep your hands out of it or make sure to drain it down before you work on it. I know you know this, but I just have to say it!!
Now back to the pics and what I was speaking of. Again, if I am way off base here gents, please don't flame me. Just trying to help. Have a good one to all. Here are the pics.
Pic one is before
Pic two is after you replaced the tubes.
Hope you get it fixed Sonar!! And again, please be safe!!!

 

[wavrider]

Maybe be one of the "New tubes" flashed over, NOS tubes are just that OLD,
When they flash, or arc they may take out the HV PS, Metering circuit or even the meters,
Old tube stuff is nice, and fun to use, but maintenance is always ongoing if you going use 40 and 50 year old equipment.

Hope you get it straightened out.

 

[Road Squawker]

...
Pic one is before
Pic two is after....

Well, what I see is a hole in the chassis that you can see a green wire and what looks like part of a cap.

In pic # 2, there seems to be some black smudge marks,... like a magic smoke trail

 

[357]

those resistors look just dusty.
I'd open the bottom and look.
If you seen a blue light and the power went out you got a problem.
Those tubes dont appear to be plate current, cathode current (however they do it) matched.
The strong tube of the sets will draw all the current and pop.

hopefully its something simple.
I'd suggest buying a sencore mighty mite to do your testing, less movement the better

 

[Sonar]

those resistors look just dusty.
I'd open the bottom and look.
If you seen a blue light and the power went out you got a problem.
Those tubes dont appear to be plate current, cathode current (however they do it) matched.
The strong tube of the sets will draw all the current and pop.

hopefully its something simple.
I'd suggest buying a sencore mighty mite to do your testing, less movement the better

Well, what I see is a hole in the chassis that you can see a green wire and what looks like part of a cap.

In pic # 2, there seems to be some black smudge marks,... like a magic smoke trail

Picture no. 2 was taken after retubing it.
The black smudge is a pattern on a seat cushion.
I won't turn the amp on again but must remove the cover in order to pack the tubes and amp for shipping. I enjoy the old equipment but I'm not knowledge enough to be putting my fingers in there.
I'm leaning towards the idea that one of the tube caused the flash. I'll get it out to Mike and let the professional do the job. Thanks for responding. Everyone has been a great help with every issue I've ever had . 73

 

[Tallman]

Tubes can get Gassy. I have seen picture tubes that would Arc and flash because of failed seals around the pins.

 

[Robb]

Playing around inside a tube amp is VERY dangerous and should be only dealt with by those who are well acquainted with those dangers. Taking your own life in your hands to work on a tube amp for the hobbyist goes beyond the definition of hobby. Unless, of course, that you have the proper gear and are well acquainted with every danger that presents itself - seen or unseen. . .

 

[Sonar]

It would be nice to enjoy using this ancient equipment and know how to repair it.
Fortunately there are still people who know how to work on this stuff and still do. As you mentioned this old equipment breaks. Heck even new equipment breaks. At this point I'm still willing to put the few bucks into it in order to keep it going. I enjoy it that much. If it were a rust bucket I wouldn't put a penny into it nor wold I like looking at it and that's important to me. I plan on purchasing a new 811 H but i still want to use the phantom as do I the sonar. It's about nastagia and nothing more (at least for me). If I could put an hf into a sonar chassis and a modern amp into a d&a housing I would. I'll send the 19 tubes along with the amp to Mike and I'm positive hell get 9 good working tubes from the batch. If he thinks replacing those resistors is necessary he'll do so. Those resistors definitely look to be original to the amplifier. I hope that after this the amp will work for a long time without issue. I'll take a picture of the tube side when I remove the cover in order to pack everything for shipping. I've little doubt that it was one of thosne "new" tubes that flashed. Two hours after the flash I turned the amp back on and keyed it and it worked without issue. I'd rather not push it so I'll get it out on Monday and wouldn't be surprised if it's back by Saturday. I hope y'all know I appreciate everyone's responses to all my questions. And I seem to have many. 73

Maybe be one of the "New tubes" flashed over, NOS tubes are just that OLD,
When they flash, or arc they may take out the HV PS, Metering circuit or even the meters,
Old tube stuff is nice, and fun to use, but maintenance is always ongoing if you going use 40 and 50 year old equipment.

Hope you get it straightened out.

 

[Sonar]

Playing around inside a tube amp is VERY dangerous and should be only dealt with by those who are well acquainted with those dangers. Taking your own life in your hands to work on a tube amp for the hobbyist goes beyond the definition of hobby. Unless, of course, that you have the proper gear and are well acquainted with every danger that presents itself - seen or unseen. . .

That's the best advice. It took me three or more days to decide to change those tubes myself. Mike walked me through it. No amount of money is worth getting electrocuted. In all honesty it's packing this equipment that's the annoying part. Having Mike fix it and pay him for his work is the easy part. Thanks again my friend. 73

 

[Sonar]

Tubes can get Gassy. I have seen picture tubes that would Arc and flash because of failed seals around the pins.

I wouldn't be surprised if that's exactly what happened.