Warning: Creating default object from empty value in /homepages/11/d132647312/htdocs/Amfone/mkportal/include/SMF/smf_out.php on line 47
Story of a Transmitter Restoration




 
The AM Forum
December 12, 2017, 07:12:55 AM *
Welcome, Guest. Please login or register.

Login with username, password and session length
 
   Home   Help Calendar Links Staff List Gallery Login Register  
Pages: [1] 2   Go Down
  Print  
Author Topic: Story of a Transmitter Restoration  (Read 13722 times)
0 Members and 1 Guest are viewing this topic.
Steve - WB3HUZ
Guest
« on: August 31, 2009, 09:48:02 PM »

W8VR has a nice story of the life of an old transmitter and its recent restoration.

http://www.w8vr.org/
Logged
Todd, KA1KAQ
Administrator
Member

Offline Offline

Posts: 4181


AMbassador


« Reply #1 on: August 31, 2009, 10:03:13 PM »

Schweeet! That's a nice looking transmitter from the start. Good job of going through it with necessary upgrades to make it solid.

Didn't know they made hot pink HV wire. I bet Fabio and Doctor Love would appreciate such an upgrade.  Grin

Logged

known as The Voice of Vermont in a previous life
W1AEX
Un-smug-a-licious
Contributing
Member
*
Offline Offline

Posts: 1447


ANAN 100 SDR


WWW
« Reply #2 on: August 31, 2009, 11:19:00 PM »

The attention to detail is remarkable. The wiring underneath each chassis is incredibly precise. Very impressive piece of work!
Logged

One thing I'm certain of is that there is too much certainty in the world.
KL7OF
Member

Offline Offline

Posts: 1981



« Reply #3 on: September 01, 2009, 01:42:02 AM »

The black wrinkle chassis look great....When a painted chassis is used, is a star washer enough to assure a good chassis ground?  The filament leads have a very tight even twist on the speech amp..Very impressive work.
Logged
WA3VJB
Guest
« Reply #4 on: September 01, 2009, 05:11:30 AM »


Reminds me of the construction style and quality of the tube-type Lambda power supplies.

Very cool stuff.

What struck me odd is modern photography on authentically old-looking brand new gear.

Doesn't Adobe PhotoShop have a tab that says "make photo look old"  ?

Logged
ashart
Member

Offline Offline

Posts: 171


WWW
« Reply #5 on: September 01, 2009, 07:57:32 AM »

To: KL7OF

Tnx OM, fer ur kind words.

I wouldn't trust a star washer to make a decent contact through a powder-coated surface, as the finish is very very tough.  Additionally, even if a tang or two of the star washer did penetrate the coating and look good on the ohmmeter, the connection might be unreliable and of higher-than-wanted impedance. 

Where I wanted a chassis connection point (there are very very few), I ground away a small circle of the powder coating with a Dremel motor and a small cylindrical grinding tool.  Consider placing the tool on one side of a chassis hole, the motor on the other with the grinding-tool shaft passing through the hole, and then grinding with the inner surface of the grinding tool while pulling on the Dremel motor.  This technique will keep the ground area reasonably concentric with the hole.

The twisted filament leads in the speech amp are but one means of reducing hum.  They are twisted evenly by fastening ends of two equal-length wires into a bench vise and putting the other ends into an electric drill chuck, the wires pulled taut, and the drill then run at low speed.

Soldering close to the wire insulation without melting it, is easy with teflon-insulated wire!

73 de al hart, w8vr
Logged
WBear2GCR
Member

Offline Offline

Posts: 3426


Brrrr- it's cold in the shack! Fire up the BIG RIG


WWW
« Reply #6 on: September 01, 2009, 02:45:55 PM »



Two questions:

1) Are there any "before" pictures?
1.5) you said there were comparison images of the before and after wrinkle/crinkle finish?
(I'm not particulary finicky about it, but I am curious...)

2) Where, when and how did you learn to do that harness lacing??

Afaik, when mfrs did harnesses they were done using a pattern board that permits the wires to be laid out and laced, then the entire harness is placed into the gear and trimmed and soldered in place... how did you do yours?

               _-_-

PS. there is a tool that is used in machine shops - I am not sure of the proper name at the moment - but it is an end mill with a short center "pin", this permits the mill to follow a hole and mill precisely around it to some diamter. I think maybe it is a shoulder mill or shoulder cutter... one of these would  be ideal for clearing the paint or powder coat from a surface. Given its small size it would work ok in a drill press or even a steady hand with a hand drill...

Logged

_-_- bear WB2GCR                   http://www.bearlabs.com
W1VD
Contributing
Member
*
Offline Offline

Posts: 401



« Reply #7 on: September 01, 2009, 07:05:25 PM »

Quote
there is a tool that is used in machine shops - I am not sure of the proper name at the moment

'counterbore' or 'spot face'
Logged

'Tnx Fer the Dope OM'.
Opcom
Patrick J. / KD5OEI
Contributing
Member
*
Offline Offline

Posts: 6738



WWW
« Reply #8 on: September 01, 2009, 07:41:40 PM »

The tool that has a short center pin  the ones I have fit in rack-screw holes. The "mill" end is wire brush and they 'dust' the paint and rust right out of there so the panel and hardware makes contact well.
Logged

Radio Candelstein - Flagship Station of the NRK Radio Network.
W3SLK
Member

Offline Offline

Posts: 2368

Just another member member.


« Reply #9 on: September 01, 2009, 08:17:54 PM »

I checked out that speech amp. What an awesome job! Man that tying and bundling of the wiring had to be nothing short of frustrating!
Logged

Mike(y)/W3SLK
Invisble airwaves crackle with life, bright antenna bristle with the energy. Emotional feedback, on timeless wavelength, bearing a gift beyond lights, almost free.... Spirit of Radio/Rush
W1UJR
Guest
« Reply #10 on: September 01, 2009, 08:18:06 PM »

Wonderful work Al, just wonderful!

The attention to detail on the mod and power supply decks are amazing,
you did a 1st class job bringing that rig back from the edge.

Great write up on powder coating by the way, I had the same
conclusions. In fact had a nice talk at the AWA Conference last month
with on OT, W3DGB, about the wrinkle painting process. Your friend's
powder coating work looks wonderful, and that finish will outlast all
of us!

A quick question on the powder coating of the xformers.
Did you coat just the end bells, or the laminations as well?
I've run into that before, but was told the powder coat temps are
not good to subject the complete xformer too, wonder how you
got around that?

Didn't see any images of the finished final deck, but
wonder if the rig on the air yet?

Can you tell us a bit about its background and history?

Your image files were amazing, I'd be curious how you shoot those,
first class pro level work. I noticed no background images, can
you share how you shoot those?
I'd doing a restoration of a 1937 Lafayette rack transmitter,
and would like to have my photo documentary look as nice as yours.

I don't think we'd had the pleasure to work on air, but
hope that add my station to your list for the maiden voyage
of this rig.  Cheesy

Tnx,
Bruce W1UJR
www.W1UJR.net
Logged
ashart
Member

Offline Offline

Posts: 171


WWW
« Reply #11 on: September 01, 2009, 11:25:28 PM »

Everyone:

Thank you all for your kind words - I appreciate each and every one of them.

Let me try to answer several posters' questions in this one reply:

1.   Are there any “before” pictures?

   Only those posted on the website.  I have none of the speech amp, but the other stages show both “before” and “after” pictures.


2.   Where, when, and how, did you learn to do that harness lacing?

   In 1953-1956, I was an electronics tech at Armour Research Foundation in Chicago.  We built experimental gear for the gov’t and we had to make it not only physically and electrically reliable, but it had to look nice.

   Yes, I used one small "cable board."  I used it for some of the behind-the-panel wiring of the final amp power supply, but it’s not visible in the pictures.  I’ll also use a big one, 2' x 8', for the two inter-deck cables, which I’ll be working on in about a month and a half, or so.  I'll photograph that process.  Much of the BigRig cable-lacing was done in situ, without using cable boards.  While one must take care to use the correct knots, lacing is an easily learnable albeit time-consuming process and I’ve seen instructions on the web.


3.   Did you coat just the end bells, or the laminations as well?

   My powder coater uses a temperature of 400 deg. F., so complete transformers cannot be safely powder coated.  Where the end bells were removable, I painted a couple and had the rest powder coated.  Where the end bells were not removable, I painted them, drying them in my home-built painting oven.  In all cases, I painted the laminations with 3 coats of black satin paint.


4.   Is the rig on the air yet?

   The final amplifier is not yet completed, so the rig has not been on the air. In fact, only today did I strip down the old final, so it’s restoration is now underway.  Take a look in my “Sundry Stuff” folder on www.w8vr.org, and you’ll see a photo of the 7 decks done so far, but not yet mounted in the rack.  I'm hoping to have it on the air for initial testing, somewhere around the first of the year.



5.   How were the pictures made?

   The pictures were shot with a digital camera, the subjects illuminated by bare-bulb flash reflected from the ceiling, with a second smaller flash as a fill-light.   The white backgrounds were done in Photoshop.


6.   Can you tell us a bit about its background and history?

   I’ve tried to do that in detail, on the website at www.w8vr.org.  On the homepage, click on the mike, and you'll be taken to a lot of relevant text.


73 de al hart, w8vr.
Logged
W2XR
Contributing
Member
*
Offline Offline

Posts: 882



« Reply #12 on: September 02, 2009, 06:46:36 AM »

Beautiful workmanship and attention to detail!

I have always said the quality in any restoration or homebrew project is in the sum of the details.

Great website, too!

We all look forward to hearing that rig on the air.

73,

Bruce
Logged

Real transmitters are homebrewed with a ratchet wrench, and you have to stand up to tune them!

Arthur C. Clarke's Third Law: "Any sufficiently advanced technology is indistinguishable from magic".
WBear2GCR
Member

Offline Offline

Posts: 3426


Brrrr- it's cold in the shack! Fire up the BIG RIG


WWW
« Reply #13 on: September 02, 2009, 10:49:38 AM »

Quote
there is a tool that is used in machine shops - I am not sure of the proper name at the moment

'counterbore' or 'spot face'

Right! CRS strikes again...

The pins are available in various diameters for a given mill diameter...

I've never seen a wire brush version Patrick! Maybe you can post a link to a supplier or a jpeg of the actual thing.

                         _-_-bear
Logged

_-_- bear WB2GCR                   http://www.bearlabs.com
WA1GFZ
Member

Offline Offline

Posts: 11152



« Reply #14 on: September 02, 2009, 12:21:28 PM »

looks like mil work! Beautiful
Logged
W7TFO
WTF-OVER in 7 land Dennis
Contributing
Member
*
Offline Offline

Posts: 2178


IN A TRIODE NO ONE CAN HEAR YOU SCREEN


WWW
« Reply #15 on: September 02, 2009, 04:35:48 PM »

Mucho Kudos! Cool
Logged

Just pacing the Farady cage...
Opcom
Patrick J. / KD5OEI
Contributing
Member
*
Offline Offline

Posts: 6738



WWW
« Reply #16 on: September 02, 2009, 11:37:41 PM »

Pilot Bonding Brushes are specially designed to clean around rivet or bolt holes. Brush diameter is ½"; Trim length is 3/8"; Brush is filled with .004" Stainless Steel wire. Only the pilot size varies, from 3/32" up to ¼".

http://www.spiralbrushes.com/end.html


* pilot-bonding-brush.jpg (30.24 KB, 330x256 - viewed 418 times.)
Logged

Radio Candelstein - Flagship Station of the NRK Radio Network.
John K5PRO
Member

Offline Offline

Posts: 1026



« Reply #17 on: September 03, 2009, 12:31:06 AM »

Is that red glyptal or just paint on the soldered connections? What is it's purpose? Have seen that in mil. equipment of that vintage. Nice work - you obviously didn't rush it.
73
Logged
W1VD
Contributing
Member
*
Offline Offline

Posts: 401



« Reply #18 on: September 03, 2009, 06:09:34 AM »

Quote
Pilot Bonding Brushes...

McMaster has them. Nice tool...

http://www.mcmaster.com/#power-brushes/=3gv25l
Logged

'Tnx Fer the Dope OM'.
ashart
Member

Offline Offline

Posts: 171


WWW
« Reply #19 on: September 03, 2009, 06:44:57 AM »

Is that red glyptal or just paint on the soldered connections? What is it's purpose? Have seen that in mil. equipment of that vintage. Nice work - you obviously didn't rush it.
73

It's red glyptal.
Logged
ashart
Member

Offline Offline

Posts: 171


WWW
« Reply #20 on: September 21, 2013, 10:40:46 PM »

At last !

BigRig has finally returned to the airwaves.  After a couple of false starts a few months ago, when the power supply chokes kept failing, I finally got that sorted out.

As of 3 weeks ago, I've been bothering everybody on 40 AM and I've done more hamming in the past 3 weeks than I've done in non-repeater operating in the past 3 years!

What great fun, and a lot of nostalgia.  It's hard not to get a little teary-eyed when operating the rig and remembering back to using it nearly 70 years ago as a kid, while sitting on my dad's lap.

Another thanks to everybody who contributed advice, counsel, and parts, and a special thank-you to the more-than extremely-generous local ham with the fabulous old-timer's junk box, who wishes to remain anonymous.

BigRig has been getting gratifying reports on and about 7290.  Look me up!

73.

-al hart, w8vr
al@w8vr.org
Logged
W3RSW
Contributing
Member
*
Offline Offline

Posts: 3201


Rick & "Roosevelt"


« Reply #21 on: September 22, 2013, 07:51:22 PM »

Absolutely gorgeous!

What is the smaller box between the modulator and driver and final decks?

Truly a 3705 / '33 set and forget Big Rig.  Cool
Bet it has Presence
Logged

RICK  *W3RSW*
ashart
Member

Offline Offline

Posts: 171


WWW
« Reply #22 on: September 23, 2013, 08:22:07 AM »

Tnx, OM, fer the "absolutely gorgeous" comment!!

Above the modulator is the modulation-monitor scope, and above the scope is the exciter, then the final.

And forgive me, but I don't understand your last comment.

73.

-al hart

www.w8vr.org

Logged
N2DTS
Contributing
Member
*
Offline Offline

Posts: 2307


« Reply #23 on: September 23, 2013, 08:42:08 AM »

That came out REAL nice!

Running home brew stuff is the most fun way to operate.
Logged
W3RSW
Contributing
Member
*
Offline Offline

Posts: 3201


Rick & "Roosevelt"


« Reply #24 on: September 23, 2013, 09:40:06 AM »

Presence

http://dictionary.reference.com/browse/Presence

Particularly definitions 6 and upwards.  Grin

Logged

RICK  *W3RSW*
Pages: [1] 2   Go Up
  Print  
 
Jump to:  

AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands
 AMfone © 2001-2015
Powered by SMF 1.1.21 | SMF © 2015, Simple Machines
Page created in 0.065 seconds with 19 queries.