Finally wore out a C16J

Until today I've been running on the same used C16Js I got with my 10EE 10 years ago. From the invoices I got with the machine they were bought in the mid-80's. After some months of slower and slower I finally decided to check the drive - on starting only one thyratron fired and on replacement the drive was back to snuff. A final tweak on the compensations to get rid of a low speed thrumming and the covers are back on and she's as good as new.

Those tubes have been known to last many decades.

My question would be,

Can you throw that no good old tube away?

I cant seem to do it, I have 3 in a box, that have been played out, just cant toss them in the trash.

I seem to remember or maybe it was in a alternative universe, that Richardson Electronics?? will rebuild those tubes? Or did ...

daryl bane said:

I seem to remember or maybe it was in a alternative universe, that Richardson Electronics?? will rebuild those tubes? Or did ...

Click to expand...

I seem to recall that, too, but suspect that they only do that for the really expensive tubes such as those in high power radio stations. I recall that the KOB 50KW transmitter pair were about 3' high and had a hurricane of air blowing on each to keep it from melting.

In the meantime the expired tube is on a shelf in my office waiting for a visitor to exclaim "I have a bunch of those - can you use them?"

How about going solid state?

Never thought of rebuilding tubes so I did a quick search - Kennetron is in Taunton MA near where I work. I suspect their target is big stuff as Russ mentions (at least one of their web pictures looks to support that) but I can easily make an inquiry if they will do the C16J's and cost. It may be attractive if there are a bunch of them to do at once.

Paul

Per daryl bane's comments, I would contact Richardson Electronics. Many years ago they bought the design and manufacturing equipment for tubes. vacuum and industrial. I have never heard of rebuilding a tube of this size, but if push comes to shove, at least know where to find replacements.

Tom

PS, they are located just down the road from me, probably 3 miles.

"I have never heard of rebuilding a tube of this size, but if push comes to shove, at least know where to find replacements."

Transmitter tubes are frequently rebuilt.

Although Richardson does indeed own the rights to manufacture a large number of old power tubes, many of the tubes which it sells are actually new-old-stock, being branded by the original manufacturer.

In an apparent record for 50,000 watt tube-type transmitter tube lifetime, CBS-owned WNEW, Morningside, MD (Washington, DC), is still on its original pair of Eimac 4CX35000 tubes in its Continental Electronics 317C transmitter. The station chief states that careful tending of tube filament voltage, and the fact that the 50,000 watt transmitter is only operated from local sunrise to local sunset (7:30 am to 4:45 pm, 9 hours and 15 minutes, during December), is the reason for the exceptionally long lifetime. The station operates with 270 watts during the remainder of its schedule, using a solid state transmitter. A solid state transmitter is scheduled to replace the CE 317C.

BeelIndustrialControls said:

How about going solid state?

Click to expand...

I see no reason to replace a functioning well kept drive, with a thousand dollar plus unit, when a simple tube replacement at at fraction of the cost, takes care of it every couple of decades.

The original Monarch drive, based upon high-power thermionic devices, is actually pretty close to being the best that can be done.

Only the later lack of availability and consequent high cost of the high-power tubes appears to be eliminated by going solid-state.

SCR-type "power blocks" were employed in the "Monarch Sidney" armature-regenerative drive (the last of the 10EEs before Monarch went with a VFD "solution", one with an ac spindle motor). Alas, drives which employ "power blocks" usually have VERY complicated controls, and tend to trade-off very high component counts in the control section for lower cost in the power section.

Indeed, both the thermionic- and SCR-based drives require "boosted" voltages in order to achieve the dc spindle motor's requirements of 230 volts armature and 115 volts field.

In the ca. 1949 WiaD, a 300-0-300 anode transformer for the armature (600 volts, center-tapped, is, practically speaking, the highest voltage possible without employing wiring methods which are exceptionally expensive) and a 150-0-150 anode transformer for the field were employed by the armature and field regulators, respectively, and both employed full-wave phase-controlled rectification, with the inductance of the armature- and field-windings, respectively, acting as chokes, hence low-pass filters for the thyratron's switching transients.

In the ca. 1960 Modular, a 300-0-300 anode transformer is still employed for the armature regulator, but one-half of the armature regulator's anode transformer and half-wave phase-controlled rectification for the field regulator, employing only one thyratron plus two series-connected "free-wheeling" silicon diodes to "complete" the cycle.

The WiaD is low-voltage controlled, using voltage-steering from a number of "receiving" tubes.

The Modular is high-voltage controlled, using current-steering from a number of silicon diodes.

Both provide equivalent performance.

Obviously, the drive which has the lowest component count is the best, and that observation would strongly favor the Modular.

However, other than the high-power tubes and associated transformers, the WiaD drive's components are all relatively low cost, and have very long lifetimes.

Both drive types share a common fault: the "audio type" transformers which are employed in the thyratron trigger circuits. Fortunately, third-party replacements are available, for otherwise, these transformers are "unobtanium" UTC audio interstage (plate-to-grid) types.

Once one has mastered the calibration of these drives, they are just about as good as it gets.

donie said:

I see no reason to replace a functioning well kept drive, with a thousand dollar plus unit, when a simple tube replacement at at fraction of the cost, takes care of it every couple of decades.

Click to expand...

Exactly. My hollow state drive is doing fine in its 51st year. And what I really like is that I have the schematic and circuit description. So, it's totally maintainable... (I wonder if these solid state drives come with that sort of documentation? )

Most solid state drives can be easily repaired by parts that are relatively inexpensive and readily available from places like digikey and newark.

1) Unless and until Beel offers to supply all buyers with COMPLETE schematic diagrams and COMPLETE theory of operations manuals of Beel's drives, Beel's drives are ... de-facto ... completely unmaintainable except by using the proverbial "shotgun" method, and

2) when a member of this Forum makes a possibly critical comment about his/her original tube drive and asks for help, and a Beel representative blurts out a completely self-serving reply such as, "How about going solid state?", I am driven very close to the point of frustration; not with the O.P., but with Beel.

I have granted Beel far greater latitude than may be warranted ... up to now.

In future, keep all Beel comments ON POINT, or risk being banned.

Now, as for Beel's requests for copies of 13EE and EE1000 manuals, and possibly others, please phone Monarch and buy copies of them.

If Beel has no respect for Monarch's intellectual property rights, which are contained in Monarch's implicitly or explicitly copyrighted works, why should we have any respect for Beel?