hallicrafters SR-2000 time delay relay?

Discussion in '"Boat Anchor" & Classic Equipment' started by WA6MHZ, May 20, 2013.

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  1. AF6LJ

    AF6LJ Ham Member QRZ Page

    Granted my cams cost four times as much as yours...
    I'm not fond of reworking the same box, even if it's ten or fifteen years down the road.

    The original caps were 200MF at 450V, I could have gone with those but wanted more available peak current and better regulation. Better regulation means two things;
    Higher average power (not that important and not my concern)
    Lower distortion of the output signal. (my main concern)

    Keep in mind one important thing, I wouldn't go with large caps in your application due to the age of the transformer.
    I can get a replacement for my SB-220 there are a number of custom made replacements out there all the way from one that is a drop in replacement rated at the same 600VA as the original one, to a 1500VA transformer that fits in the same spot with minor modifications to the internal side panel.

    Your radio will see some use and will sit in a museum and should remain functional for those times when it is taken out for a spin on the bands. I would be very proud to have an SR-2000 and it would not see daily use.
    (They don't take the Star of India out every weekend and race it, and they certianly don't take it out in bad weather)

    So for a number of reasons you wouldn't want the same cap, They do offer a cap in your voltage and capacitance range that is very reasonably priced that has the same low ESR.

    In short you restoring a classic.
    I am building a daily driver.
     
  2. AF6LJ

    AF6LJ Ham Member QRZ Page

    Oh and Jim if you want a more in depth discussion on the cap issue it will have to wait until I get back.
    Going out with a girlfriend (not that kind ) for brunch, window shopping and a movie. (The new Star Trek movie)
    But I would be glad to go further into the subject when I return at your request.

    I do need to re-state one thing.
    The SB-220 project is not a restoration, it's taking a popular amplifier and customizing it.
    What Pat is doing is great and he is going about it very well.

    If I had a Z-28 and wanted to drive it every day, take it on long trips and have a little fun with it, the last thing I would do is restore it to stock condition. There is no fun in driving a fifty year old car that handles like a tuna boat and takes half a block to stop.
     
  3. N2EY

    N2EY Premium Subscriber QRZ Page

    1) How much internal heating actually happens

    2) How much difference it makes to the transformer, diodes, etc.

    3) How much difference there is in static and dynamic regulation

    4) How much difference there is in fault current
     
  4. N2EY

    N2EY Premium Subscriber QRZ Page

    I'm more interested in actual numbers and calculations. Take your time, no hurry.

    Not sure what your point is there.

    'MHZ's restoration has elements of customization too. Otherwise he'd be using exact replacements of the originals, or as close as possible.

    Your points about not beating the PS-2000 transformer are good.

    The SR-2000 notes on AXN's site show a number of changes made during production runs due to problems, and a couple of worthwhile changes worked out afterwards. Apparently there were a number of problems with the early ones!

    As for "daily driver", it all depends what someone likes. For some folks lack of an automatic trans would be a deal-killer, for others it's not an issue at all. Etc.

    ----

    One more thing: Even when fixed up, a rig like the SR-2000 isn't a good FD rig except in special situations. Here's why:

    1) Unless everybody who uses it knows what they're doing, there's a good chance it won't last the FD period before somebody blows it up.

    2) It needs a decently regulated primary power source - preferably 240 volts.

    3) FD rules are such that the power multipliers break at 5 watts battery (x5) and 150 watts (x2). Worse, the entire group gets the multiplier of the highest-power transmitter. So if one transmitter of a multi-multi runs high power, all the others lose theirs. Better to have everybody run 100 watts output and get the multiplier.
     
  5. WA6MHZ

    WA6MHZ Premium Subscriber QRZ Page

    The SR-2000 is out of the trunk! Plus the HX-10, which is a real DOG! Fortunately, the front panel and knobs are in good shape, but the cabinet is a rusted hulk!

    [​IMG]

    I added screws to the SR-2000 cabinet to hold the covers on and Chassis in place.

    Here are photos around the Chassis

    [​IMG]
    [​IMG]
    [​IMG]

    There was a note in the K9AXN docs where it said to look at the Relay to see how hot the 6AQ5 gets. What is strange is that in THIS unit, the OTHER side of the relay is burnt!!! Maybe at one time, the relay was 180 degrees from what it is now

    [​IMG]

    The tuning knob insert is in bad condition. I sanded the outer ring and it looks better now. Going to need LOTS of NOVUS #2 to clean up the panel and knobs. Plus some touch up paint in one small area. That won't be a problem. Trickiest thing is to match the paint to the right color. I start out with a basic grey and add black paint a drop at a time to match the tint.

    [​IMG]
     
  6. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    SR-2000 doesn't look bad.

    My HX-10 had "shiny" knobs. Looks like yours has the "dull" finish knobs. I don't know when or why they changed, but the shiny knobs looked very nice.
     
  7. AF6LJ

    AF6LJ Ham Member QRZ Page

    I agree with Steve the SR-2000 looks in decent shape.
    The HX-10 is also a fine addition.
    Very Cool.
     
  8. N2EY

    N2EY Premium Subscriber QRZ Page

    Thinking about the SR-2000 got me wondering why we never saw more rigs like it.

    In the late 1950s there was the Cosmophone 1000, but only a handful were made and it wasn't a legal-limit rig IIRC.

    There were some tubed Swans and Yaesus that used multiple sweep tubes to run several hundred watts, but again they weren't legal-limit.

    So the SR-2000 was pretty close to unique, offerering the then-legal-limit in a transceiver, using real transmitting tubes. Of course the power supply was external, but external power supplies were almost universal back then. So why didn't anybody else make a similar rig? Or did they?

    I have two guesses:

    1) The problems of packing that much RF power into the same box as the rest of the rig were deemed not worth the advantage of simplified tuneup.

    2) The market was too limited. Back then, a lot of countries didn't allow their hams to run that much power, so foreign sales would be small. Many hams back then would "build a station a box at a time" - first a transceiver, then an external VFO, then an amp, etc. Spending a lot of money a little at a time was easier than spending a lot of money all at once.

    3) The overall cost was not competitive. Back in the 1960s you could get a pair of new Cetron 572Bs or a single Eimac 3-400Z/500Z for $34 - I suspect 8122s cost a lot more then. An amp based on those triodes was a lot simpler and could be used with any 100-watt class transceiver or separates.

    Anybody know for sure?
     
  9. KE3WD

    KE3WD Ham Member QRZ Page

    I think your three points pretty much sums it up there, Jim.

    Any other points might apply, but you've hit the main headers IMO, the rest would just be smallbeans icing on that cake IMO.

    One of those smaller bean points might have to do with the fact that QRO was historically not as important to operators who were able to erect antennas that worked better than the compromise antennas we see the younger hams of today being forced to contend with. In that frustration, they often attempt to go QRO into compromise antenna, usually falsely thinking that to be a solve for a bad antenna. And damn the neighbors, eh?

    IMO the most important of your three points given is COST, though.

    And cost of operation should also be considered along with original purchase price, the QRO rig, when in need of tubes and other components, comes with a higher repair pricetag, not to mention the higher danger possibilities inherent.

    The modular concept, exciter that can be used onair followed by purchase of an amp later on, is likely to be the easier path, not only for entry into the hobby, but for successive upgrading as well. It is rather prudent to be able to keep the amp and swap the exciter, or vice verse. And multiple exciters (radios) can be used with the one amp, too.


    73
     
  10. WA6MHZ

    WA6MHZ Premium Subscriber QRZ Page

    Wonder if anyone ever converted these to 4CX250B's? Seems like the tube is the same size.
     
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