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Author Topic: N1ESE's Chippewa Thread  (Read 49968 times)
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N1ESE
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« on: November 05, 2007, 08:08:43 PM »

Brought home a new to me Heathkit Chippewa today.  It is complete but very dirty.  I think the best thing to do is re-build her from the ground up.  Although it was supposedly working before it was put away in storage.  I'm starting this thread to document the restoration process.  I will likely need the collective input of ya'll as I do this re-build as I have never done a restoration like this.

Here are the pics, this is how I brought her home:

Front view:
http://n1ese.qrpradio.com/AM/Chippewa-1.jpg

Top view:
http://n1ese.qrpradio.com/AM/Chippewa-2.jpg

See the broken meter in the first pic?  Here's a NOS replacement:
http://n1ese.qrpradio.com/AM/Chippewa-3.jpg

- JT
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Pete, WA2CWA
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« Reply #1 on: November 05, 2007, 08:17:13 PM »

How's the power supply section?
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N1ESE
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« Reply #2 on: November 05, 2007, 08:21:38 PM »

How's the power supply section?
Turned out to be homebrew, I was hoping it was the matching HS-1 but it's not.  Here are some pics of the HV supply that came with the amp:

Transformer:
http://n1ese.qrpradio.com/AM/HVSupply-1.jpg

Capacitors:
http://n1ese.qrpradio.com/AM/HVSupply-2.jpg
http://n1ese.qrpradio.com/AM/HVSupply-3.jpg

- JT
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w3jn
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« Reply #3 on: November 05, 2007, 08:26:24 PM »

Dude, that's a helluva strapping PS  Grin Grin
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N1ESE
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« Reply #4 on: November 05, 2007, 08:29:05 PM »

Dude, that's a helluva strapping PS  Grin Grin
Tell me about it, I can barely lift the transformer.  I need to figure out how to safely discharge the capacitators before I kill myself working on this stuff.

- JT
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« Reply #5 on: November 05, 2007, 08:31:13 PM »

Matching supply was model KS-1.

Hopefully you got a schematic of the power supply to get a feel as to how it was designed. Hard to tell from the pictures you just posted. Actually I probably would be more concerned with the supply then the KL-1. Other than the broken meter, it just looks like it needs a good cleaning and component checking.
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Steve - WB3HUZ
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« Reply #6 on: November 05, 2007, 08:33:21 PM »

Fire hydrant red. Cool!
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N1ESE
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« Reply #7 on: November 05, 2007, 08:41:13 PM »

Hopefully you got a schematic of the power supply to get a feel as to how it was designed. Hard to tell from the pictures you just posted.

Unfortunately, no skizmatic for the supply.. it was basically the transformer, capacitor deck, and a few terminal strips inside the rack cabinet.
 
- JT
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Steve - WB3HUZ
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« Reply #8 on: November 05, 2007, 08:43:46 PM »

Should be easy enough to trace out and make your own schematic.
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N1ESE
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« Reply #9 on: November 05, 2007, 08:49:01 PM »

Should be easy enough to trace out and make your own schematic.
How do i go about identifying what all the terminals are on that big transformer?  There are a couple terminals on the other side of the transformer as well.  I also have a big mod-iron with a bunch of terminals I need to identify as well.

All this is much different than the QRP rigs I am used to building but I know to be careful with high-voltages. 

- JT
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N1ESE
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« Reply #10 on: November 05, 2007, 09:00:29 PM »

UH-OH! Now you've done it! Let's see how many pages of posts this brings!

Yeah, I know I'm an idiot but we all have to start somewhere and I am capable of learning.

- JT
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N1ESE
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« Reply #11 on: November 05, 2007, 09:20:19 PM »

Might as well start the ball rolling on this, are the terminals on the other side designated with an X?
Negative.  On the other side, we have three terminals.  Two of them are about half way up the side and centered on each half of the transformer.  Someone hand wrote "sec." on each of these.  At the top of the transformer is the third terminal with a big ceramic insulator.  Both halves of the transformer are connected to this point and someone hand wrote "C.T." with an arrow pointing to it.  So it is clear these are the secondaries with a center tap.  No other connections are on this side of the transformer.

Thanks

- JT

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WQ9E
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« Reply #12 on: November 05, 2007, 09:38:29 PM »

I will throw out a guess, 3 phase primary...  If my guess is correct, not to fear because the transformer can still be used on a single phase line with slightly reduced ratings and I don't think that would be a problem given the size of that piece of iron!

Rodger WQ9E
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Rodger WQ9E
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« Reply #13 on: November 05, 2007, 10:14:09 PM »

Hi Mack,

The H marked terminals seem to be typical of some three phase units so that was the reason for my guess.  Hopefully if it is 3 phase someone can offer expertise in that area.  There is an article in the May '95 Electric Radio starting on P.8 that offers some information on connecting/using 3 phase transformers to single phase lines.  JT, if you find that you have a 3 phase unit and you don't subscribe to ER I can make a copy for you.  However, given that you have jumped into vintage with both feet you might want to call the nice folks at ER and get a set of back issues since you will find them full of interesting and informative info!

Rodger WQ9E

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Rodger WQ9E
N1ESE
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« Reply #14 on: November 05, 2007, 10:14:38 PM »

And remember before applying AC to anything, THIS STUFF WILL HURT OR KILL YOU IN THE BLINK OF AN EYE!!!

Definitely, that is why I am trying to figure out what I am dealing with first.  I don't have 220VAC in the shack yet so I won't be applying power anytime soon either.  I'll ohm it out when I get it in the shack (hopefully tomorrow).  I can barely lift it, it is still on the porch, and we nearly broke my dolly when we tried bringing in the rack cabinet and the transformer.  I'm going to U-Haul tomorrow to get a hefty dolly.

- JT
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N1ESE
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« Reply #15 on: November 05, 2007, 10:21:03 PM »

Actually, the power supply project may have just come to a grinding halt.  Does this look like a leaky cap to you guys?

http://n1ese.qrpradio.com/AM/LeakyCap.jpg

Thanks

- JT
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N1ESE
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« Reply #16 on: November 05, 2007, 10:27:24 PM »

remove the strap between H2&3

BTW, that strap is a capacitor.  Can't tell from looking at the pic.

- JT
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N1ESE
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« Reply #17 on: November 05, 2007, 10:37:42 PM »

Slight leaks around the insulators are not uncommon, clean it good and place a ring of silicon seal around the base of the insulator, probably won't cause any problems.
Sounds good, thanks Mack.  I'll wait until I discharge the caps.   Cool

- JT
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N3DRB The Derb
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« Reply #18 on: November 06, 2007, 12:37:53 AM »

yeah hat looks like a leaker to me. just remove it. unless it's cap input it wont amount to anything. check it, but dont despair unless the voltage rating is exceeded or it's a cap inpoot suckply.

I would worry more about making that thing safe than makin it work for now. I think the way it's made it's a deathtrap waiting to happen. you got a lot of cleanup on that RF deck to worry about before you even fire the supply, unless you like the smell of carbon tracks, becuase that all you will get.

1. see how the supply is made. make a bangstick for yourself to discharge the caps.

2. document. dont assume the builder knew what he was doing. assume the exact opposite, that you can and will do it better than him.

3. start figuring out how you want it to be laid out.  Personally, I would turn it into a Henry Radio pedestal type all in one unit, self contained, on big casters.



make the framework out of 2 X 6" and wrap yer sheet metal around it. But get that supply and cap bank under cover. Unless you wanna b a SK.

btw, the pic comes from the best place to get a used henry amp in the country. the one in the pic is a bargains - -such amps are lifetime buys.
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N1ESE
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« Reply #19 on: November 06, 2007, 06:04:29 AM »

I would worry more about making that thing safe than makin it work for now.
Yeah, I have no plans in the near future to make this power supply work.  It's obviously setup for 220VAC 3-phase and I definitely don't want to deal with getting that in the shack at this time.  I'm just trying to figure out what the heck it all was/is.  I will likely build a smaller supply for use with the Chippy.  The Chippy needs 3000VDC, 450 ma.  I have a feeling the power supply that I have now it much beefier than that.

- JT

 
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N1ESE
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« Reply #20 on: November 06, 2007, 06:48:31 AM »

How should I go about discharging these two capacitor banks?

One person told me to just lay a screwdriver across the bars.  However, this would likely result in the screwdriver becoming welded to the bars wouldn't it?

Should I carefully remove each bar and deal with each capacitor individually?

Once discharged, I'm putting this mess aside for awhile.   Lips sealed

Thanks

- JT
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N1ESE
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« Reply #21 on: November 06, 2007, 07:11:26 AM »

Seems like a resistor mounted to an insulated stick is probably the best way to handle the situation?

- JT
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W1ATR
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« Reply #22 on: November 06, 2007, 08:01:03 AM »

Fire hydrant red. Cool!

You mean fire hydrant yellow?

I don't think that's a 3ph tranny there. I have big 3ph open frame chunks here and they all have 3 windings, or cores, or whatever. Judging by where the taps are going into the windings on the primary side, that trans looks like it has a nice selection of outpoot voltages.

Does that RF deck still have the 4x4's in it, or did someone knock it up with some 500z's? Can't see a 4-400 base in the pic.

Looks like a nice score and what will be one helluva power supply when your done. Very first thing I would do is break apart that bank of caps. Having those long large straps across the tops leaves way too much "accidental contact area". Tying them together with that 1" bar stock is useless anyway, We're talking about Kilovolts here, not Kiloamps. Tongue

Start at the tranny and get a nice print drawn up, and when you get to mounting the caps, wire them up with HV wire leaving the only exposed area's right at the terminals. I like to use GTO-15, it's a 14ga. neon sign wire that's available everywhere cheap.

I believe the original PS was a choke input, but that doesn't mean nothing now. It's clear this PS is wayy hairier than the original stuff was.

I would pick up a HV probe, like a Fluke 80K, and when you make your Jesus stick, a resister type is good, but make sure you also come up with a way to dead short everything right to ground. Don't use cheap clip leads to tie cap terms together. The roachclips don't have enough bite to hang on if they get bumped and can come off when your not looking. Make a set with some high quality battery clamps. Build your safety gear as though your life depends on it not to fail. Because it does.

 
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N1ESE
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« Reply #23 on: November 06, 2007, 11:10:55 AM »

Does that RF deck still have the 4x4's in it, or did someone knock it up with some 500z's? Can't see a 4-400 base in the pic.

Yup, here's a picture:
http://n1ese.qrpradio.com/AM/4-400A.jpg

Says Eimac 4-400A on each tube.  The amp is very stock and complete, just very dirty and the face plate is discolored with lots of nicotine buildup.

Thanks for the other comments.

- JT
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N1ESE
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« Reply #24 on: November 06, 2007, 11:52:06 AM »

It looks like the load resistors might still be wired to the capacitor banks in the pic, if they are then the caps are discharged already.
Wires from resistors to caps have been cut at some point so I can't take that chance.   Shocked

Just pulled the bottom cover on the Chippy, more pics coming up.  it looks like there has been one mod made to the rig as there is a MOSFET installed in the LV supply area.

- JT
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