ad: UR5CDX-1

HalliCrafters SX-100 rebuild

Discussion in '"Boat Anchor" & Classic Equipment' started by KD0OXU, Mar 9, 2012.

Thread Status:
Not open for further replies.
ad: L-HROutlet
ad: l-rl
ad: Left-3
ad: Subscribe
ad: L-MFJ
ad: l-BCInc
ad: Left-2
  1. W9GB

    W9GB Ham Member QRZ Page

    Ian -

    IF you are going to change-out/repalce the rectifier tube .. THEN you need to go through the power supply section.
    I always like to get the HV DC supply in these boatanchors to be SOLID/RELIABLE, so I can focus on other issues (RF, IF, Detection, Audio sections).

    1. Electrolytics capacitors (high voltage) should be checked OR replaced.
    2. Shoddy soldering is likely earlier repairs / component replacements from former owner(s) .... bad soldering (factory) on 1950s Hallicrafters is possible (but rare to find these days).
    3. Check AC power cord; fuse amp value correct; and bypass/safety (X, Y) capacitors on AC input to transfromers are safe for operation around your children.
    http://www.justradios.com/capacitors.html

    --
    73 de greg
     
  2. W9GB

    W9GB Ham Member QRZ Page

    Ian -

    IF you are going to change-out/replace the 5Y3 rectifier tube .. THEN you need to go through the power supply section (powers those 14 tubes with correct DC voltages).
    I always like to get the HV DC supply (and 0A2 regulator tube) in these boatanchors to be SOLID/RELIABLE, so I can focus on other issues (RF, IF, Detection, Audio sections).

    1. Electrolytics capacitors (high voltage) should be checked OR replaced.
    2. Shoddy soldering is likely earlier repairs / component replacements from former owner(s) .... bad soldering (factory) on 1950s Hallicrafters is possible (but rare to find these days).
    3. Check AC power cord (fraying); fuses (correct A value); and capacitors on AC input to transformer (bypass/safety/supressor: X1/Y1, X2, Y2) operational for safe operation around your children.
    http://www.justradios.com/capacitors.html

    --
    73 de greg
     
  3. K9STH

    K9STH Platinum Subscriber Volunteer Moderator Platinum Subscriber QRZ Page

    Not only add a fuse in the "black" wire, but also add a 3-wire line cord with the green wire going to the chassis. Otherwise, with a 2-wire cord, you will have about 60-volts AC on the cabinet. Not much current, but enough that you can get a "tickle" from touching the unit. Remember, those units with a 2-wire line cord were designed to have the chassis grounded with a "real" ground. The green wire in a 3-wire line cord takes care of grounding the chassis / cabinet.

    The 3-wire cord should have the black wire to first to the fuse and then to the off / on switch. The white wire goes to the power transformer primary winding directly. The green wire connects directly to the chassis.

    Having a 3-wire power cord is a safety factor. I refuse to send out any unit that I work on that comes in with a 2-wire cord without changing it to a 3-wire cord. "Originality" is one thing and safety is a completely different matter.

    Glen, K9STH
     
  4. KM1H

    KM1H Ham Member QRZ Page

    The SX-100 is not a radio Id recommend to cut your teeth on as if it isnt overhauled and aligned exactly right it wont work very well.
    Forget the tube tester as unless you replace certain parts first you stand a good chance of causing permanent damage to a few other components. I dont think your daughter will appreciate the smell of a frying transformer. DONT replace the 5Y3 with SS, if you still need one give me an address via PM and I'll send one.

    Show us a photo of the bottom side and I'll point out some things to be aware of. This isnt the world of module swap repair, you have to get your hands dirty right into the component level with a soldering iron and other tools. While I own and rebuilt one its not on my favorites list and is strictly for display, I love the looks of it but was told to stay away from them when I was a HS ham in the 50's. Ive rebuilt maybe 20-30 over the years and it does what many expect so almost everyone is happy.

    Carl
     
    1 person likes this.
  5. KD0OXU

    KD0OXU Ham Member QRZ Page

    SOB I just wrote a bunch of stuff and hit the wrong button!!! Anyway, thanks for the tips I realize I got a lot ahead of me and I've got two more receivers my buddy is sending me in trade for a buddipole a Hammurland HQ 180 and a hallicrafters SX-28. I used to do component level swaps and I know how to work a multi meter pretty well. I just haven't done some of this in so long and I have never done tubes. I am a satellite communications operator maintainer by trade for the military but we haven't done component level stuff since the late 90s when I first came in.

    I really wish I hadn't hit the wrong button and lost the other post, but again thank you guys so much I've got a lot to learn and a lot of people here seem to be giving me the right path to take on this.

    Oh yeah back on the SS, you mean solid state? if so I will not be doing that I have a 5Y3 on order should be here the 13th.
     
  6. KM1H

    KM1H Ham Member QRZ Page

    Yep, SS = Sand State and what you need is hollow state. While SS diodes work they create other problems by having almost no voltage drop and will raise the B+ to levels you dont want. A new 5Y3 will last 30-40 years when its happy.

    OK on your experience, I was a Navy ET a couple of years after Sputnik so learned all this silly tube stuff the proper way and never got completely away from it. The real jobs that paid the bills OTOH were at leading edge R&D often with defense contractors.

    Carl
     
  7. W9GB

    W9GB Ham Member QRZ Page

    The Hallicrafters SX-28 is prized by some, panned by others
    But for 1939 state of art.
    IF you need a soldering station or VTVM, speak up -- can send
    those your way. Tobyhanna, PA likely did component level
    repairs for your Army gear.
     
  8. KC8YLT

    KC8YLT Ham Member QRZ Page

    I would agree with many of the other guys, I would leave the 5Y3 in that radio. I had one of these radios a few years ago, when I got it the receive was way down on all the bands. The problem was a few resistors out of tolerance, The problem was they were located in the metal box located on top of the main chassis. I had to take a picture and make a drawing of where all the wires comming out of it went, disconnected them opened the box up and replaced ALL RESISTORS in it. There arent many but it is good practice to change them all on the spot. After that I had a really good performer! Best of luck with your radio! Carl KC8YLT.
     
  9. KD0OXU

    KD0OXU Ham Member QRZ Page

    I know Tobbyhanna, been there on a few occasions in my day, got to stay in a nice resort hotel in the Poconos for a week while touring there for a refit and learning about a new upgraded Satellite system. I do have a decent military type soldering station and access to many many great tools from work. as far as the VTVM would this be anything I need in addition to my tester? I am learning slowly but my limited knowledge was that tubes either worked or they didn't, which common sense would say that they may work but not get the full potential for what ever reason.

    You all have made me feel like I've joined some special club or something I really love the support and am about to go through every box in the garage to find my fluke so I have a good multi meter and start testing the other stuff. Got a day where the wife and one child are gone to learn to kill, clean and cook a chicken, a dieing skill in this world lol.

    Thanks again for all the great advice and pointers, now I really need to get this stuff done so I don't waste all the wisdom comming my way.
     
  10. KM1H

    KM1H Ham Member QRZ Page

    A high quality signal generator for alignment, none of the Heath, Eico, Knight, etc crap. A HP 606A or 606B would be decent since they are typically around $50-75 BUT you need to overhaul them first which is pretty easy. Then you need a counter since the SX-100 IF has to be exact and you will need to align the SG first anyway.

    There are better generators but they cost much more than your radio and when they crap out its not an easy road back.

    Id suggest the AN/URM-25D or later but they are a PITA to overhaul, one already done is about $150 and up.....50's technology.

    Carl
     
Thread Status:
Not open for further replies.

Share This Page