N1ESE's Chippewa Thread

[N1ESE]

I'm not at all SURE that the transformer is 3 phase, it's just a possibility. Ohmmeter tests of the primary windings will tell you for sure.

Yeah, I'm going to check it out later today.

I've never owned a Chippewa, so I looked at the KS-1 PS on the internet and it is 500 ma continuous and 1 amp peak, so I'd be building for 3000vdc@1amp continuous.

Yeah, that's the best plan I think.  Build a dedicated supply, I think the original builder had several amps or modulators in mind when he built this beast.
 
- JT

[Todd, KA1KAQ]

Well, other than being dirty as hell, it looks to be in decent, restorable shape at least. The panel should clean up nicely and buff to a shine, can't tell what the chassis has on it, maybe just oil from the blower and accumulated dust?

Tubes look like they were ridden hard and put away wet, though. Maybe it's just the lighting. Hold a piece of white paper behind them and take a peak. Brown staining and spatters don't mean the tubes are bad, just driven hard. 

Good deal to get the replacement meter with it. The case might not be difficult to find, but the scale would be another story. I'm guessing you got the cabinet with it, just took it off for the shots?

Make a decent cage to cover the PS with. Something stout to keep things at a distance. You might find an original supply for it someday, but at least this one should work well in the meantime. Production figures I heard were in the multiple hundreds, can't recall exactly.

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.

One of these sold at Deerfield for $450, complete. W1DEC sent it down the road along with his 75S-3B and a few other trinkets. I never cared for the looks of 'em, along the lines of a HB linear in a 30S-1 case. Always liked the Alphas, kinda miss my old PA-77 some days. The original 'brick-on-the-key' amp.

[W4EWH]

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

 

JT,

The guy I got it from was planning on building a modulator, and he sized the supply to power both the amp and the mod deck. I'll look through my file drawers and see if I come up with his address.

HTH.

Bill W1AC

[N1ESE]

Here are some more pics of the Chippewa with the bottom covers removed:
 
http://n1ese.qrpradio.com/AM/Chippewa-4.jpg
http://n1ese.qrpradio.com/AM/Chippewa-7.jpg
 
Some type of modification was done to it.  This is an NTE51 which is a high Voltage, high speed switch transistor.  Here's a pic of the transistor:

http://n1ese.qrpradio.com/AM/Chippewa-5.jpg
 
Some of the caps look new:
 
http://n1ese.qrpradio.com/AM/Chippewa-6.jpg
 
I just hauled in the cabinet this was all mounted in.  Pics of this beast coming up in a bit.

- JT

[Todd, KA1KAQ]

Some of that soldering looks like it was done by a gorilla. You sure have got your work cut out for you, but plenty there to work with.

Yep, it's a long way from the world of QRP. 

[N1ESE]

Rack cabinet pictures:
 
http://n1ese.qrpradio.com/AM/rack-1.jpg
http://n1ese.qrpradio.com/AM/rack-2.jpg

Blower:
 
http://n1ese.qrpradio.com/AM/rack-blower.jpg
 
Wiring at the bottom where the HV transformer was mounted to the floor.  Secondaries were wired to the terminal strip in the first picture:
 
http://n1ese.qrpradio.com/AM/rack-wiring-1.jpg
http://n1ese.qrpradio.com/AM/rack-wiring-2.jpg
 
- JT

[Todd, KA1KAQ]

Wow, someone went through the trouble of painting up a relay rack to match. That's a lot of Heathkit green!   

[N1ESE]

Says Eimac 4-400A on each tube.

Actually, upon closer inspection.. only one of the tubes is a Eimac brand 4-400A.  Not sure what the other tube is, there are no markings on it and it looks a bit different.

- JT

[WBear2GCR]

When you go to test the transformer, use a low voltage transformer and a fuse if you like to fire up the primary - or what you think is the primary.

In the case of a big step up like 120v:6000 CT or so, I'd use a 5 volt AC source.
Then the ratio of ~1:60 will give you like 300vac across the entire secondary... not quite so bad... I often use a 10v source since that gives you a quick and accurate reading of the ratio.

To "short" those caps? How about taking two cleep leeds from one of those resistors and putting an insulated stick on one lead, clip the other lead to one of the cap rails and take the other lead with the insulated stick and put it across. Then wait, it should be down to nil pretty quick. Put a temporary shorting wire across the bars or the terminals of the caps. Done.

                         _-_-bear

[N1ESE]

I just ordered a high voltage probe today, if I'm going to be working on this stuff.. I need one anyway.

- JT

[N3DRB The Derb]

I bet that little bit of solid state in there has something to do with the tubes idle current.

[N3DRB The Derb]

I'd take the Alphas too, but the older Henrys are damn nice amps. At $450 that was a steal.

[WBear2GCR]

I just ordered a high voltage probe today, if I'm going to be working on this stuff.. I need one anyway.

- JT

Nooooooooo!!!   

Yes, you need a HV probe later!!

When you go to fire up an unknown transformer one definitely does not want to put line voltage on it!! Not terribly safe nor a good way to figure out the taps.

The best way is to use a small step down transformer, as I said preferably one that makes it easy to figure out the ratios later, like a 5vac, 10vac, or for those who are terminally lazy or without a calculator 12vac (10x less than line voltage). It can be rather small, nothing big needed, an amp of current rating is quite sufficient.

(or you can use a random low voltage transformer with the secondary set to your favorite voltage with a variac on the 120vac primary side of the LV transformer...)

This also works fine for finding the turns ratios on mod iron.

This lets you test without popping the breakers in the house, without sparks, without deadly voltages and no smoke. 

                     _-_-WBear2GCR

                       

[N1ESE]

Nooooooooo!!!   
Yes, you need a HV probe later!!

Bear, sorry.. you misunderstood and I wasn't.  I am not powering up the transformer anytime soon.  I bought the HV probe so I could see how many volts are still in the capacitor banks.  This was suggest by a few people earlier in the thread.

- JT

[WBear2GCR]

You can play with the HV probe no prob.

As Mack said, just take and short them out already - use the resistor.
They'll only have some minor atmospheric charge unless something wierd happened to them... the internal leakage will drain them down usually, or worst case leave them with some voltage but not backed by any Joules... usually.

Then tie them down with a few bits of #20 solid wire, keep them at ground, if you worry about such matters... 

JT, keep in mind that just like a QSO on the air, the reader to poster ratio is fairly high here, so opportunities to spell out things like that are useful to others who might merely be lurking and reading the posts, and may actually go off and try some things that they're not 100% on solid footing with are valuable. In the case of high voltage high current transformers it's not a minor detail. So, I try to nail down things like this, lest someone get the wrong impression and make a dangerous or fatal error as a result.


                           _-_-WBear2GCR

PS. why wait to test the iron(s) - GO FOR IT!!

[N1ESE]

So, I try to nail down things like this, lest someone get the wrong impression and make a dangerous or fatal error as a result.

Mack, I appreciate your concern and experience.  I'm scared enough to respect what I am dealing with here as I start to work with high voltage stuff.
 

PS. why wait to test the iron(s) - GO FOR IT!!

Actually, the iron will likely be going to NEAR-fest in the spring along with the capacitor bank.  I'm never going to need anything as potent as this setup.  I don't know if I even want to mess with the Chippewa.  There is an OM who contacted me who has the matching supply and he's been bugging me to sell him the Chippewa so I just might.  I'm thinking of going the Class-E route where I am a bit more friendly with solid state.
 
I'll get my barefoot screen modulated transmitters on the air in the meantime.
 
- JT

[N1ESE]

Ok, I just finished stripping the rats nest of hanging and disconnected wires from the rack cabinet.  Here are pictures of the remaining pieces of the high voltage supply.  Still not sure how this was all wired originally as everything was cut up pretty good with almost nothing attached.
 
Big honkin' relay, this was mounted right next to the big honkin' power transformer near what I believe to be the primary side:
 
http://n1ese.qrpradio.com/AM/relay.jpg

The secondaries on the big honkin' transformer were connected to this bridge rectifier panel:
 
http://n1ese.qrpradio.com/AM/diode-panel.jpg
 
Back to cleaning up the cabinet.
 
- JT

[KB2WIG]

For watts its worth, I'll wrap solder around the terminals of oil filled caps, and other points of HV...Eye glasses help for thoes 'little' accidents.

 All oil filled caps in storage get the solder treatment.........   klc

[N1ESE]

Well, it turns out that my Chippewa has been heavily modified.  All the screen/bias control circuitry is missing and other parts put in their place.  I am definitely in weigh over my head now with none of these changes documented anywhere.  Not sure what to do now, guess I will sell it as a parts unit as it will be next to impossible to restore it back to original condition.

- JT

[WQ9E]

Hi JT,

I have an unmodified Chippewa and I will be happy to take some high res photos of the insides as a guide to you also.  Just let me know.

Rodger WQ9E

[N1ESE]

JT, you know what's "way over my head" better than the rest of us might. The screen supply and grid bias circuits are pretty basic and easily recreated in the Chippewah from the schematic in the manual.

I'm just suddenly a bit overwhelmed and this is suddenly a much more extensive project than I originally envisioned.  There are actually chassis parts missing as well.  To do this amp justice likely would mean tearing down and rebuilding from step one in the manual.

I dunno what to do.
 
- JT

[flintstone mop]

Hey Sonny,
You got yourself a serious project there!! A lot of TLC needed but you will have a very nice strong signal for AM.
It won't happen over night.
Prolly next radio season or in a couple of months if you have lottsa time and some dineros to fix/replace anything outta spec.

Very nice amplifier.....Chippewa capable of 160M??

Fred

[N1ESE]

Here's a picture of one problem area, this horizontal coil should not be here.  There is supposed to be a vertical plate here with a bunch of voltage regulator tubes and a clamp tube mounted to it.
 
http://n1ese.qrpradio.com/AM/Chippehack-1.jpg
 
- JT

[N1ESE]

I have an unmodified Chippewa and I will be happy to take some high res photos of the insides as a guide to you also.  Just let me know.

Rodger, I'd greatly appreciate this.  I'd like the raw images straight off your camera as I run pretty high resolution on my screens here.
 
Thanks
 
- JT

[N1ESE]

I'm just venturing a guess here but I'd say somebody added the extra coil for 160m band coverage and solid stated the screen supply. Both easily undone and put back to stock.

160M coverage is the general consensus of the Heathkit reflector as well but several people told me it'd be extremely difficult, if not impossible, to find some of the missing parts I need.

It's really a personal choice for you to make, somebody will relieve you of the Chippewa if you decide to not continue with it.

I have received a few offers to buy it as is but I don't know if they are fair offers or not.  My gut tells me they are too low.  I am split quite evenly on whether to keep it or not.  I guess I just don't want to get it all disassembled and half way through the rebuild and hit a major roadblock. 
 
- JT