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Astron Power Supply

Discussion in 'Radio Circuits, Repair & Performance' started by WA6TXU, May 1, 2012.

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  1. WA6TXU

    WA6TXU Ham Member QRZ Page

    I own an Astron RS-20A power supply that I use to power my ICOM 735 and some of my VHF rigs. The red on-off rocker switch has gone bad. I cannot find any serial number on my switch (only thing I can discern is "Made in Mexico" on it). There are numbers on it related to different countries (e.g. UK, FR, IT) but no U.S. number. I tried to match any number on the switch I could find with all of the rocker switches in the Mouser Electronics catalog. Seems they have every rocker switch known to man (oops, or woman). Astron Corp. has not responded to me. Guess I am small potatoes. Until I can replace the switch I have am QRT. Can anybody give me a valid part number, or where I can purchase the switch? I would suspect that the only place I can get it is Mouser. Probably not Radio Shack!! I suspect that every Astron power supply uses the same rocker switch (at least the RS series anyway). Would appreciate any help you could provide. Thanks. Dave, WA6TXU.
  2. W9GB

    W9GB Ham Member QRZ Page

    Dave -

    The NEON bulb in the rocker switch has burned out. Neon bulbs typically have a ~ 20,000 hour life.

    Very SIMPLE replacement, these illuminated rocker switches used by Astron fit the
    North American Appliance STANDARD "Snap-In" rectangular cutout !!!!
    Appliance industry uses primarily white trim, while radio and electronics mfg. use the black trim.

    Be a SMART shopper, I have seen these switches sell from $3 to $12 !!
    Some electrical supply houses/distributors "mark up" these switches!!

    Specifically, Astron uses the Carling LR-series "Curvette" illuminated rocker switches.

    Go to Page 294 in the GC Electronics catalog, Figure 8 : switches 290-297.pdf

    GC Waldom Electronics part number: 35-3740
    GC Electronics is available at many retail electronics stores.
    This GC part is the Carling switch, in deep red.

    Dark Ruby Red Color (NEON/120 VAC)

    DO NOT use the non-standard Radio Shack switches
    (I have repaired far too many bad idiot hacks)
    BTW You should have ACK Electronics (Birmingham & Atlanta) on your speed dial for these easy parts!
    ACK is a GC Electronics retailer -- call them!


    BTW I keep this switch in my standard repair parts inventory!!
    Last edited: May 1, 2012
  3. WA6TXU

    WA6TXU Ham Member QRZ Page

    There is more of a problem here. When I push the rocker, the light comes on (but I have to keep it pressed for the light to stay on). However, when I let go of the switch, the rocker switch springs back, and the light goes out. The switch does not stay in the on position. I turned on the rig while keeping the switch pushed to the on position (with bulb lit) and still no power to the rig. I release the rocker and the switch returns to the off position. It is like flipping a circuit breaker in your house and it keeps returning to the position from which you flipped it (like a short somewhere in the system is over-riding the circuit breaker). Haven't seen anything shorting out in the power supply, so that returns me to the belief that it is a bad switch. It just suddenly happened a few nights ago with no warning. Therefore, since the neon lamp goes on when I keep the rocker depressed, I would say that it is not a bulb issue, but rather a problem with the switch itself. Thank you for the sources for a compatible switch. I am not sure I clarified the problem, but I hope so. Dave. WA6TXU.
  4. W9GB

    W9GB Ham Member QRZ Page

    Really does not matter -- your switch is BAD and you need a new switch.
    You know where to call to order it (or drive and pick-up) OR have it shipped.
  5. WA6TXU

    WA6TXU Ham Member QRZ Page

    Appreciate your help Greg. I will order a switch tomorrow. One important thing I should have mentioned in my last post was that even with the power supply unplugged , the rocker switch would not stay in the ON position. Agreed, no short, just a bad switch. Again, thanks for all of your help. Dave.
  6. WA7PRC

    WA7PRC Ham Member QRZ Page

    While you're waiting for the replacement switch, short across the bad switch (and leave the PS on) until the replacement arrives.
  7. W9GB

    W9GB Ham Member QRZ Page

    Astron used this Carling number: LRA211-RW-B/125N (Translucent Pale Red, Black trim, 125V neon)
    for the North American 120 VAC units, a Carling switch with 240 VAC neon is used for Rest of World.

    GC Electronics 35-3740 should be: LRA211-CR-B/125N (Clear Red), or LRA211-RS-B/125N (Translucent Red)

    IF you are ordering from Mouser, they carry BOTH styles:

    Mouser Catalog Page - Carling Rocker Switches

    LRA211-CR-B/125N (Clear Red)

    LRA211-RS-B/125N (Translucent Red)

    BTW This same switch is used in 1980s Weller WTCPN, WTCPR power units.
    Last edited: May 1, 2012
  8. WA6TXU

    WA6TXU Ham Member QRZ Page

    Hi Greg,
    Thanks for the info. I ordered my rocker switch today. You have been a great help. Dave.
  9. WA9SVD

    WA9SVD Ham Member QRZ Page

    It SHOULD be obvious, but the switch doesn't really need to be illuminated to work. A simple SPST rocker switch WILL function properly, and most of us have the supply shoved in a corner where we never even notice the illuminated switch!

    But be careful about advice concerning shorting the present, defective switch, on the off chance there's an additional problem with the supply. If you DO short the switch, unplug the supply first (DUH!) and it would be wise to plug the supply into a power strip and use the power strip as an "ON-OFF" switch. That way, if there's an additional failure in the supply, the circuit breaker in the power strip should trip before catastrophic failure. (Keep ALL equipment off or disconnected when you first re-power the supply, until you determine it's functioning properly (save for the faulty switch.)
  10. WA6TXU

    WA6TXU Ham Member QRZ Page

    Thanks Larry. I have ordered a new switch, and since it should get here in a few days, I don't think I will short the current switch, just to get on the air. As you said, there is a possibility that something else in the power supply could have caused the switch to go bad in the first place. The new switch was only $2 (plus a significant shipping cost from Mouser). But when you are in West Georgia, you do a lot of on-line shopping. Hi. Dave, WA6TXU.
  11. W9GB

    W9GB Ham Member QRZ Page

    Dave -

    The replacement rocker switch uses 0.250 inch QuickConnects ...
    again a common termination method from Appliance industry, used with pre-made wiring harnesses.

    Older Astron supplies used solder lug versions of the rocker switch.
    In those cases, you would need to crimp or solder the 0.250" QuickConnect
    to the wires in the Astron power supply.
    Last edited: May 3, 2012
  12. KD8DEY

    KD8DEY Subscriber QRZ Page

    I wonder how hard it would be to find an equivalent in BLUE??!!

    Blue seems to be all the rage these days.

    I Was thinking about trying to replace the blown bulbs in my 35's meters
    with Blue LED's instead of paying Mucho dinero to Astron for replacement meters
    just to have them light again....
  13. W9GB

    W9GB Ham Member QRZ Page

    Carling makes Blue Illuminated Rocker Switches.

    The BLUE versions are often found with 12 V bulbs for Automobile/Truck industry.
    Carling LR-series catalog
    Short version

    Lighting your meters?
  14. KO6WB

    KO6WB Premium Subscriber QRZ Page

    Say it is so!!!! You are supposed to want to get on the air even if you have to use a bycicle generator to do that. Gheese....what's the matter with operators today?;););)
  15. WA7PRC

    WA7PRC Ham Member QRZ Page

    Astron's cheapo $2 switch is the likely cause of its own failure, not "something else". Mine lasted 30 years (so far) by not ever being turned off.

    The Idiom Press LED illuminator is a GREAT way to get that ugly "spotlight" effect. I don't see the point in illuminating meters that have questionable accuracy and poor precision.
  16. W9GB

    W9GB Ham Member QRZ Page

    Since the Astron power supply (linear models) use that standard rectangular cutout, you have access to MULTIPLE switch manufacturers, such as: Cherry, C&K, Carling, others, and even Japanese based NKK.

    In northern Mexico, across from the USA border -- you can find mfg. facilities for many of these switch mfg.
    About 7 years ago, Carling inventory was low due to back orders -- I used Cherry switches during that period (they worked fine).
    I never understood lighted meters, when my linear supply is not on the radio desk or on the floor.
  17. WA9SVD

    WA9SVD Ham Member QRZ Page

    Those have, unfortunately turned out to be "famous last words."
    PROPER troubleshooting techniques call for eliminating ALL possible failure modes and elements before replacing a part, only to find it fail in short order. While hgighly unlikely that anything other than the original switch i the source of the failure, there was one glowing "symptom,": that was not properly diagnosed. Even when the OP held the switch in the closed position, the radio failed to turn on, if I understand correctly. THAT to me raises a big, red flag, until troubleshooting indicates the absence of other error, even if it's not closing the Power Supply switch long enough to allow power to come up to spec. I tend to use more passive devices (that may be sacrificed because of power supply or P/S regulation) such as lamps, headlamp bulbs as opposed to expensive pieces of equipment as a "dummy load."
  18. W9GB

    W9GB Ham Member QRZ Page

    Fair enough, but the part is faulty and a new now will be required.

    The search for the reason for this AC switch failure -- would start on the AC Line input and the PRIMARY side of the transformer. AC Power or Voltage surges can be one cause, this can damage a power switch or destroy the MOV found across the transformer primary.

    A VOM or DVM can be used to test the bridge rectifier and diodes.

  19. KE3WD

    KE3WD Ham Member QRZ Page

    BS-O-Meter reading: 0_________/__100

    Stop trying to scare the guy.

    Failure of the power switch ONLY in Astron power supplies is damn near legendary.

    Those switches, designed for things like coffeemakers where the load is resistive, quite often fail due to the inductive load of the transformer primary. When switched off, the field falling in the xformer primary makes a healthy back emf that results in a spark/arc across the switch contacts.

    After a while, the contacts get torn up and become resistive, which creates heat, which in turn damages the mechanicals inside the switch and its history.

    Replace the switch.

    Placing a good quality 0.1uF capacitor that is rated for at least 250VAC (and 600VAC is better) across the switch contacts can snub the arcing and make a new switch last a lot longer. There should be a cap across there, suspect it if there is, add it if there isn't.

  20. KA9MOT

    KA9MOT Ham Member QRZ Page

    Not to overlook the elephant in the room........ An RS-20A is not enough PS to run your IC-735 at full power. On 100W peaks you are overloading it and it probably isn't doing your rig any good either. If it were me, I'd fix the one you have (for your lower powered radios and shack accessories) and find a larger (at least 30A) supply.
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