[ARC5] Bear ''raslin', or, "The ATC and Me" (Very Long)

[Kenneth G. Gordon]

Thank you, thank you, thank you, thank you, thank you!!!!!!!

I have an ART-13 which was given to me by a very good fellow. It has not 
been so much as looked at for at least 40 years.

I am carefully hoarding your notes and will put them in "a safe place" until I 
am able to use them.

Ken Gordon W7EKB


On 4 Jul 2010 at 1:30, arc5 at ix.netcom.com wrote:

> An old friend asked me to help him get an early ATC
> (sea-going ART-13) on the air.  I'm close.... ;-)
> When something is tough, I have a habit of calling it "a bear," 
> meaning: "tough as wrestling a bear, and just as likely 
> to chase you up a tree."  Or three...
> 
> I have resurrected some hard-case BAs, 
> but I ain't never had as tough a "bear" as this ATC. 
> I thought I'd pass along a few tips.  
> This isn't a "step-by-step"; a beginner should not even
> try to 'rastle an ART-13, so I'm not going to cover
> all the obvious stuff you already know.  
> It's just a "heads-up" on a few issues 
> for anyone who's "feeling froggy" enough to dust-off an ART-13.
> 
> 1.  Don't be in a hurry.  You're not going to finish in one night.
> Probably not in one week.  It's going to be a long time before you put
> power to this black monster. Slow down and think about everything
> you're going to do before you do it.  The ART-13 has a reputation for
> being a "tough" transmitter.  Don't you believe it.  This thing is as
> fragile as any 70-year-old, and just as hard to handle. Tipping or
> turning it over without care and caution will result in bending or
> breaking something, like the terrible "CRACK!" you hear when you turn
> it over and the screwdrive you left on the bench crushes the vacuum
> relay.... Don't ask me how I know.
> 
> 2.  If you don't have the Maintenance manual, 
> don't even think about turning the first screw.
> Guessing and fudging just won't do on this one.
> Get it.  Read it.
> 
> 3. The "Screw Gremlins" can smell you working
> on an ART-13 from miles away and they will
> come running.  So get your bench and tools organized.
> You'll need a full can of De-Ox-It or such 
> (NOT "Blue Shower;" that stuff should be sprayed 
> all over the guy that invented it).
> Have a way to sort and keep screws and washers
> (Ice trays turn over too easy.  
> Don't ask me how I know that one, either).
> Important- A good, comfortable pair of insulating gloves.
> You're going to be tweaking things that bite.
> And if you get across that 1100 volts.... 
> well.... you won't be worried about your ART-13 anymore.
> 
> 4.   All of you know not to try and pull the big tubes out 
> by the plate cap or glass, right?  (Again- don't ask).
> Put a screwdriver through the vent holes in the back,
> under the tube bases and *gently* pry the tubes up 
> out of their sockets.  Make sure you've released the 
> tube clamps at the bases before you try it.
> 
> 5.  OK- here's the first time the bear is going to bite
> a hunk out of you.  In order to lubricate the autotune
> correctly, you're going to have to remove at least 
> "A" and "C" autotune mechanical thingies, one at
> a time (they are not interchangeable).   
> Otherwise, you can't get to all the worm gears 
> or the line shaft bearings.  
> Instructions for removing "A" are in the most common 
> copy of the Maint. manual at 5-40 para 3 and 
> for removing "C" at para 4.  
> If you're lucking enough to have the big, full-on 
> ATC maintenance manual 
> NAVAER 08-5Q-6, FEB 1944,  
> the instructions are on the bottom of page 83.
> 
> Here's the first indication that even the revered
> Collins can engineer something stupid:
> They don't tell you in the instructions about 
> this little, brass dog-bone looking thingie that connects 
> the autotune dial to the thing it's controlling.
> It has an indexed, toothed wheel on each end
> and is about 3/4 of an inch long.  It's not secured
> on either end; it just fits into toothed, 
> indexed slots on each end.
> So naturally when you pull the autotune out, 
> the little dog-bone thingie falls out, bounces on 
> the bench and flys down to the floor.
> If you don't find it, you are a dead duck.
> Worse is trying to fit it back together.
> Don't move the clutched autotune stuff,
> but you can rock the control shaft back and 
> forth until you get the cursed stupid thing to 
> engage on both ends.  This shouldn't take more 
> than, oh, about 58 tries.  If you force it,
> it will bend and you will be unhappy.
> Whiskey might help.
> Don't try to take out the "B" HF Oscillator 
> multi-turn unit unless it's broken.  
> More on this nasty gadget later.
> 
> 6.  Once you get the autotune back together, 
> go do anything else until your sanity returns.
> Then make sure all the locking bars on the tuning knobs
> are tight and use a large-ish flat-blade screwdriver 
> on the end of the autotune line shaft and gently give it 
> a few turns to make sure nothing is binding or busted.
> If you are one of the blessed that has the original 
> crank for the shaft, send me a private email 
> telling me where you put it 
> and when you go to sleep at night.
> 
> 7.  Here's a great big "gotcha" that happens in a lot
> of WWII rigs- Ground lug oxidation.
> I put a meter from the PA chassis to the Osc 
> chassis and it read 300 Ohms.  Almost every ground
> screw and lug in the whole rig was hi-Z.  Give 
> a slight tightening turn to every chassis screw you 
> can see, and that will fix most of them.  
> Check each one.
> But- unfortunately- there are several more deep 
> in the guts of the this big black troll, and you 
> must get to them.  For instance: there's a stack
> of parts right next to the 813 socket and it has 
> a ground lug on one of the screws.  Yep- it was 
> hi-Z.  You have to take the back cover off 
> (Not the screws holding the two relays.  The relays
> stay and the cover swings out of the way on the 
> relay wires)  in order to fix it.
> But that's an easy one.  The real hair-puller is:
> 
> 8.  The Frequency Multiplier chassis.
> Yes- it has to come out.  And it's a pain to
> take out.  Putting it back is worse.
> Grid resistors 25% high and hi-Z grounds.
> Two slightly-leaky caps (look at the diagram
> and you can test these parts without 
> pulling the chassis.... kinda).
> 
> If you need to pull this chassis, the procedure
> is in the ATC manual on pages 70-71, and
> in the more common ART-13 maint. manual 
> on pages 5-22 to 5-23.
> Mark the wires from the Multipliers coils
> or you will weep.  I used colored dots on
> the coils and wires to get them back
> correctly.  Be careful with the "folded" 
> connections to the bottom of the coils.
> And be gentle- the coils can break
> and some of the cores flake a little.
> 
> Important: Before you get up your courage
> and remove the Multiplier chassis, get some 
> fingernail polish and mark the dial, the front switch 
> and the back switch so you are certain to 
> get them back together correctly.   
> The bandswitch segments are held together 
> with another Collins screw-up; a "U"-shaped clip 
> that holds tension on the segments and which falls-out 
> if you hold your mouth wrong.  This clip is  
> not sold at WalMart.  If the clip comes loose,
> this can allow the rear bandswitch (2nd Multiplier) 
> to become mis-aligned,
> and it took me three blankettyblankblank times of 
> pulling this chassis in and out to finally get it fixed,
> all because I marked the front switch and neglected
> to mark the back.
> I fixed the hi-Z grounds and
> replaced the bad resistors.  The two caps-
> a screen bypass and a cathode bypass- 
> leaked less than 200 microAmps at full voltage,
> and would have been a nasty chore to replace,
> so I left them in there.  So shoot me....
> All the grid caps and tank caps were fine.
> 
> More "gotchas" on the Multiplier chassis:
> 
> The tube clamps will hang when you try to remove
> or replace the chassis.  A screwdriver can push
> them out of the way.  The doubled lead that goes
> to the LF oscillator will also be a pain unless you
> remove it.
> 
> The big brass posts that connect the tube plate caps 
> are fragile and will snap-off easily, as I found out.
> I wire-brushed the nut on top of the insulator
> and the end of the broken post and, using
> a good frame iron and non-acid flux, was able to 
> solder the post back in place with enough solder
> to keep it secure... I think.
> 
> The round pink-n-brown multiplier tank caps
> that you use to tweak the multi stages are 
> also quite fragile.  Their adjustments will be "stuck."
> The connection post on them is secured internally
> with a rivet about the size of a flea's butt.  It will 
> break off if you're not gentle with the cap, and
> you won't find one of these at WalMart either.
> This ATC won't be transmitting on 14.4-18 MC
> because of this.  Yet, you're going to need to apply
> some amount of force to break the cap adjustments
> loose so you can peak them.  This flexes the connection,
> so you might want to see just how much juju you can 
> get out of the rig without tweaking before you risk it.
> I had to tweak this one, so I used a flat screwdriver
> as a "punch" and the rubber handle of another screwdriver
> as a mallet, and very gently tapped on the adjustment posts
> over and over until the rotor came free.
> Some of you mechanical whizzes 
> probably know a better way.
> Use the insulated gloves when you tweak these
> caps, or you shall surely get "lit-up" with 400 volts.
> 
> 9.  Once the transmitter was putting out RF, 
> I attempted to see the limits of the HF Oscillator.
> Next thing I knew, the rig was stuck with the 
> osc. railed high, and wouldn't tune freq anymore.
> So off came that end cover again.
> 
> This Osc-Mulitiplier set-up is a mix of genius and stupid.
> Ok- let's see if I can describe this.
> Imagine a coil.  It has a core, which is fixed to a
> long rod.  The rod is threaded on one end
> and is fixed in place so it can't turn on the other end.
> The threaded end of the rod is screwed into the 
> threaded center of a cylinder.  So if you turn the
> cylinder, the threaded rod can't turn (because it's fixed
> at the other end), so the rod moves in and out of 
> the cylinder.  That's what moves the core back
> and forth in the coil, and that's how you tune
> the freq of the HF Oscillator in an ART-13.
> It's a PTO.
> 
> So far so good.  Now-  the fixed end of the rod
> is secured to a yoke that moves cores in and out
> of two smaller coils, which are the tank coils of
> the two multiplier stages.  So- as we turn the 
> PTO dial, the core on the big threaded rod moves
> in and out of the PTO coil, changing the freq, 
> and at the same time, the big threaded rod 
> (which is fix and can't turn- it just moves in and out) 
> moves the mulitplier tank coil cores, 
> peaking the mulitplier stages in sync with the PTO.  
> Genius, right?
> 
> Well, yeah... except for the way the long threaded
> rod is secured to the yoke, which both keeps the 
> rod from spinning and moves the two smaller cores.
> It's secured to the yoke with a #10 nut, a star washer
> and a drop of 70-year-old Glyptol.  That's it.  
> Nothing else.  No key, no indexed slot, nothing
> but friction and old paint.  What were you thinking, Art??
> So, naturally, the paint gave way when I got near 
> one end of travel and the nut and washer loosened.
> Now the long threaded rod spins, the PTO core spins
> and nothing moves anymore, regardless of where the 
> PTO dial is set.  I was able to tell by the marks on 
> the guide bar where to re-secure it at the high end
> of travel, within a rotation or so.  I had to re-flex the
> lock washer and secured the nut with a glob of 
> "Shoe Goo" (I think you could repair a battleship
> with that stuff...it's good).   It could just have easily 
> turned loose in the middle of travel, in which case 
> I'd have had a hard time getting it close.
> So if you have an ART-13, do yourself a favor-
> take off the case end and put a drop of something
> on that nut to keep it from coming loose.
> 
> I guess that's all I can think of for tonight-
> I still have a "gremlin" or two in the rig.
> The 837 filament is intermittant, and I think that's going
> to be another hi-Z ground lug at the LF osc. socket.
> We'll see.  
> 
> Hope this is helpful to any brave soul who tries
> to tame this "black bear" of a rig.
> 
> 73 Dave AB5S.
> 
> p.s. In case you didn't know---
> I'm loving every minute of fixing this rig :-)
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