My SB-102 restoration project

Discussion in '"Boat Anchor" & Classic Equipment' started by KE4CQ, Apr 25, 2018.

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  1. KE4CQ

    KE4CQ Premium Subscriber QRZ Page

    This is my first and only tube rig. I bought it almost 2 years ago. Since then I have replaced most of the caps and resistors. I really enjoy the radio but because of its age, I had problems every now and then and have spent many hours trying to troubleshoot stuff. So, I decided that if I am going to keep this radio and enjoy it for many more years, maybe I should do a ground up restoration. So, a few days ago I setup my work space, pulled out the soldering irons and started taking it apart. Many thanks to George Blahun, KS1U who after I watched his video on youtube, gave me the inspiration to do this!


    The radio has many wires with bad soldering iron burns on the insulation. So I decided to replace all wires and coax with new. I will replace the wire with 20 awg PTFE stranded and replace the coax with RG316 which has a PTFE dialectric.

    Here is the link for my wire source: https://www.ebay.com/itm/20-AWG-Gauge-Stranded-Wire-Kit-10-Color-25-ft-Each-0-0320-Dia-PTFE-600-Volts/372256373767?ssPageName=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649


    All resistors and caps will be new - I might leave a few of the mica caps. Most new resistors are 1 watt. There are a few ½ watt resistors in place mainly because it was what I had on hand.


    I already had the RG316 on hand - purchased at a hamfest a couple of years ago.


    When I got everything removed from the chassis I cleaned all the boards with soap and water then dried with compressed air. I wet sanded the chassis to an almost new shine.


    Most hardware is new stainless.


    I hope you enjoy the pictures and I will continue to add pics as I make progress. I think I am limited to 10 pics per message.


    If you want to you can join this photo gallery which will have all the pictures and you will be able to see the new ones as I add them. https://photos.app.goo.gl/DpLnzM2QmHeTuxv33


    So far I have had a lot of fun and I know the reward will be great. It’s kinda neat to be able to experience what others got to experience back in the day...except for the “unboxing” part.


    Kevin

    KE4CQ
     

    Attached Files:

    W6ELH, N2EY and K7TRF like this.
  2. KE4CQ

    KE4CQ Premium Subscriber QRZ Page

    Here are a few more pics.
    Kevin
     

    Attached Files:

    KL7KN and N2EY like this.
  3. KE4OH

    KE4OH Ham Member QRZ Page

    All I can say is ... Wow!! What an undertaking. Sounds like fun, though!
     
  4. W3RU

    W3RU Ham Member QRZ Page

    Kevin,

    Best of luck in this endeavor! I have heard of others totally disassembling a somewhat complex Heathkit, but you have certainly taken this to a new level. The SB-101/102's are most certainly worthy of this effort if I had to vote for one particular kit.

    If you plan to restore the silk screening on the rear apron, I'd be most interested in your process and outcome. I have always viewed this as a stumbling block for a full-blown restoration, along with the front panel.

    I anxiously await the rest of your pictures, and I have bookmarked your site for periodic checking.

    Regards,

    Jack W3RU
     
  5. W7UUU

    W7UUU QRZ Lifetime Member #133 Life Member Platinum Subscriber QRZ Page

    Wow!! A huge project indeed!!

    But you know that you can't start a thread like this and not now follow it through, right?! Folks (OK, myself and a pretty big group of like-minded) are going to want to see this through to the end, with final checkout and "back on the air". No bailing out midway through, never to be heard of again (a certain HW-9 project comes to mind :rolleyes:)

    I really admire the step in the direction you're taking. May the Gods of Tube Rigs watch over you the whole way in such a "ground up" restoration :)

    I want to do something similar one day in the coming years, but with a vastly simpler rig like a DX-60b or DX-40. I can't imagine starting with a pretty advanced rig like an SB-101/102

    Dave
    W7UUU
     
  6. N0TZU

    N0TZU Platinum Subscriber Platinum Subscriber QRZ Page

    Excellent!

    I bought an SB-102 here that had been mostly cleaned up and brought to working order. I did some more work on it including several more parts in need of replacement and a few other issues, but nothing like the full job you are doing!

    I look forward to additional reports!
     
  7. K7TRF

    K7TRF Premium Subscriber QRZ Page

    Awesome project!

    One thought as long as you're rebuilding the wiring harnesses. The SB-102 runs a shielded line up to the front panel volume control and then back again. This line is bundled with the filament supply running to a number of tubes and is can introduce 60 Hz hum on the audio output. I saw a dramatic drop in supply hum on my audio by running my own RG-174 line up to the pot and run separately from the cable bundle. I found the advice for that mod somewhere on the web but at least on my SB-102 it helped a lot. As you're building up your own cable bundles you might think about ways to incorporate this audio line in such a way that it doesn't couple to the filament supply lines.
     
    N0TZU likes this.
  8. KE4CQ

    KE4CQ Premium Subscriber QRZ Page


    Thanks, Jack. Regarding the print on the rear of the radio, for a simple solution a fellow ham friend suggested using decals that can be made using an inkjet printer and your pc to customize the font style and size. Here is the website for the decals: https://www.micromark.com/search?keywords=decal paper
    I am not concerned about keeping the radio all original so to speak. Even if I used a good label maker with black ink on clear ribbon it would look a whole lot better than what was there before I sanded it. :)

    Kevin
    KE4CQ
     
  9. KE4CQ

    KE4CQ Premium Subscriber QRZ Page

    Thanks for this suggestion! I will look into this. I will also need to go through all the SB102 service bulletins.

    Kevin
    KE4CQ
     
  10. N0TZU

    N0TZU Platinum Subscriber Platinum Subscriber QRZ Page

    Yep, I also did that mod - highly recommended. I ran the coax tightly along one of the frame members.
     

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