The AM Forum

Help;Just bought a Henry 2KD without the high voltage supply,I think I have all the parts for it in my junk box.The problem is the tubes have something that looks like a silver gray washer 5/16 dia. by 1/16 thick with a 1/16 hole in the center floating loose in the tube .If I put the tube upright it fits right into the glass dimple in the bottom.Is this normal ??,or should I start looking for some 3-500's.Also any thoughts on the power supply would be helpful.I have a 3925 volt @400 ma xfmr.,7.5 kv @1 amp diodes,lots of 2400mfd @450vdc caps, a 1.4 henry choke@3kv,and a variac that will handle the load.THANKS ,Joe WB2FQD ??? PS They are marked EIMAC 8163/3-400Z

Dunno what the vintage of your Henry 2KD is...

At least the earlier Henry 2K series was set up only for 3-400 tubes!
There is insufficient height in many cases to fit the 3-500... you have to check.
Sometimes you can "squeeze" the socket lower with some washers to make the clearance, and/or add some dielectric to the area above the plate connector, cut down a plate connector or two, etc...

Not sure what's flopping about in there, maybe a bit of glass?? Washer, odd!
Perhaps some getter material.

BUT, if they work, so what!

The PS should be set up to pull down with the loading resistors (see the Henry schematic) in place to ~2800v. As you start to get up to 3kv. things in the linear like to arc over quite a bit, depending on atmospheric conditions... ymmv.

            _-_-bear

Oh, some folks have changed out the filament choke setup for a dual set up and run separate filament iron, so you can put in a single tube - sometimes useful for testing tubes and/or in a pinch. Can't do that with the fils in series as they now are.

It looks just like a washer with  serrated edges.Serial# is 142 with 6 1/2 inches from deck to top of cabinet.I have to build the power supply before I can test them,but they look good ,no burn marks or flash over inside,I hope they are good .Thanks JOE

Look at the other tube, do you see one, but up near the bottom of the plate assembly??

How about shooting a jpeg and posting it?
Take a magnifying glass and hold it flush to the lens of the camera, focus by moving the
whole thing and looking at the LCD display, then shoot, no flash.

             _-_-bear

Are yours Eimac 3-400Z/8163? With the vertical fins on the anode and the little aluminum heat dissipator cap?

Go to this link and pull up the PDF I have there, see one on the right of the two 3-500Z triodes:

http://amfone.net/Amforum/index.php?topic=6841.0

I am holding one in my hand now, and there is no washer like what you describe visible anywhere inside this Eimac tube. I wonder if there was some change or you got another brand, that uses such a part? If it sets down in the bottom, between the leads that go through the glass seals, maybe OK as long as it doesn't move and bridge two leads! However, if it is indeed part of the filament structure, such as a flag getter, it won't function down there, and your tube may become gassy overtime if it is overloaded some, and if the getter isn't activated by the filament heat.

The tubes are both EIMAC and they both have the little washer.The filaments on both seem to be good (not open).I will try and get a picture.Thanks

Here's what I would do.

Pin 1 to 5 should have continuity...  That's your fils.

2, 3 and 4 should all have continuity (if memory serves me well...  This ain't no 4-1000 :) ) as those are the grids.  If you don't have continuity between 2 3 and 4, or continuity between 1 and 5, then the tube is shot.

If you DO have continuity between pins 1 to 2, 3 or 4, or pin 5 to 2 3 or 4, then you have problems (think fils to grid short).

If you can, bring the fil up slowly, and monitor current.  Would help (memory, again), if the grids where directly grounded, or you used a real fuse of some type when bringing them up.

Shane

For Sale 2 christmas ornaments,look just like a 3-400Z,also sounds like a tiny  bell when shaken due to small silver washer.First tube made it to 2.25 volts @8 amps before filament blew open,second one went to 2.8 volts @11 amps before shorting to the grid.Those small washers must be  what holds the top of the filament in place.Thanks for  all the  info.Also where is the best place to buy some 3-500Z's .Joe.

I get mine thru RF Parts shipped about $160.00 a piece...

http://www.rfparts.com (http://www.rfparts.com)

Hi -
Please understand, you can't just plug-in 3-500Z's in one of the older Henry 2K's originally made for 3-400Z's. They just won't fit in the vertical space available- I know, I have one!

I did, however, hook-up a pair of 4-400A's triode connected in place of the 3-400's, they (at least the ones I used) had the exact same envelope, hence the same overall height. I tied the control grid and screen together, then proceeded as if they were, in fact, 3-400's. Worked like a champ. Putting in 3-500Z's and getting enough clearance is a real pain!

73
Don

The 3-400z has 2 inches of space between it and the top cover,the 3-500z only has 1 inch.Building a 1 inch spacer out of aluminum square stock for the top cover is no big deal.You get 2inches of space and no chassis mods.Joe WB2FQD

How about using one of those flying saucer  flat anode caps like ameritron puts on they're 500z amp? It gains you another 5/8" or so of clearance.

The 4-400A's will work just pissa. Just connect all of the grids together with some braid and when you come across some cheap triodes, remove the braid and plug them in. 4-400's are a lot easier to find.
Keith
WA1HZK

Nothing to connect the socket already does all the work for you, iirc.

But the 4-400s I have are taller than the 3-400z I have, and they don't really fit
into the 2Ks that I have, but they are all different depending on year and model # from Henry... afaik.

the shorty plate cooler/cap is good, I wanted to make some that look like a --->*
to do that trick... still you need some extra clearance, which you can get with spacers on the tube sock!

           _-_-bear

Ok  what gives ,am I missing something.The top cover of my amp is 12 1/4 by 13 with 4 quarter turn screws.If I use 1 inch square tubing as a spacer it will end up flush with the back and the sides(ok the sides are rounded, but should still look good)and the front will be recessed about 3/4 inch and I will have my 2 inch clearance from the top of the plate cap.Nice simple solution ,no work inside ,polished aluminum looks good,and its still rf tight.Just got two used 3-500z's ( they're EIMAC ) which have passed the hot filament test,will just have to wait until the HV supply is done to see if everything else works OK.