hallicrafters SR-2000 time delay relay?

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

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  1. K9AXN

    K9AXN Premium Subscriber QRZ Page

    Hi Pat:
    No need to replace the diodes. I stated that I have not seen a diode fail in 35 years. That's true but there is a problem. When these P-2000's are shipped they have to be screwed to a piece of plywood and braced so the case never feels impact from any angle. To do this a longer set of screws are used. If you look at the diode block, you will find one screw hole is directly over it. Install a long screw and you have a shattered diode block --- caution --- check for shipping damage. If you need a diode block let me know.


    Kindest regards Jim K9AXN
     
  2. N2EY

    N2EY Premium Subscriber QRZ Page

    I'd rather not find out the hard way.

    73 de jim, N2EY
     
  3. KC9UDX

    KC9UDX Platinum Subscriber Platinum Subscriber Life Member QRZ Page

    In that case, the safest thing to do is power the rig from a latching relay energised by a momentary switch.
     
  4. N2EY

    N2EY Premium Subscriber QRZ Page

    Exactly the issue. Better to wait a couple of minutes than fry an 8122 or two!

    What you have done is a good compromise because the P-2000 is not changed. If you ever find the right TDR it's a quick swap.

    What I would do would be to build an adapter to use a different Amperite and a small relay that provides the reset feature. Small metal box with 9 pin plug on the bottom, Amperite 26NO180 on the top, relay and voltage doubler inside. Much simpler and foolproof, plus period-correct technology. But hey, I'm still running 866As....

    Just wrap up the old cans and phenolic boards. Someday you or someone else may decide to reuse them.

    As K9AXN points out, it's a bit of a detective story to figure out which caps should be replaced and which shouldn't.
     
  5. N2EY

    N2EY Premium Subscriber QRZ Page

    The safest thing is to do what I've done for almost 30 years in the Southgate rigs: the time-delay relay energizes a stick relay which then deenergizes the time delay so it can cool off. Simple and foolproof. There's a Hint and Kink in QST about it.

    Why Hallicrafters didn't do that - and use the right 180 second TDR - is a mystery. Perhaps the time-delay feature was an afterthought?
     
  6. KC9UDX

    KC9UDX Platinum Subscriber Platinum Subscriber Life Member QRZ Page

    Actually, that's not the safest thing. Imagine if the power goes out during the time delay heater cool-down time. Until the time delay heater is back to ambient temperature, the power supply can still turn on too soon.
    A manually resettable relay would be safer. Or, a timer to guarantee off-time to cool the heater completely.
     
  7. N2EY

    N2EY Premium Subscriber QRZ Page

    That's true but it's more complex. How does the off-time timer run without power? And the chances of a power failure during the cooldown time that would cause a problem are pretty small.

    The timer I use in the Type 7 supply is a 115NO60T. Got it used many years ago. In over 30 years I have worn out exactly two 866As, and they were used when I got them. I credit the TDR systems with part of that.
     
  8. WA6MHZ

    WA6MHZ Subscriber QRZ Page

    Today, Sat Jun 8, I came in at 5AM to get some work done on the P-2000 Power Supply. First,the small electrolytics were all replaced. The 8uf/500V was replaced by two 20uf/250V in series. The can was replaced by two 20uf/350V tubulars. And the bias supply had three more 20uf/250Vs.

    [​IMG]

    Now, the top was finished with the remaining 100K power resistors, and the boards were screwed down in place.

    [​IMG]

    After checking the power supply voltages, it was time for first light off.

    [​IMG]

    After doublechecking everything. the P2000 was plugged into the SR-2000. To my delight, the dial lamps lit up on the rig. After the time delay, the relay clicked and I now had voltage on the SR-2000.

    HOWEVER, there was no sound from the Speaker!!!! Playing with the Preselector showed no response on the meter or even the slightest click from the speaker.

    I pushed the HV ON red button and it latched into place. With my VTVM, I measured MORE than 1500V HV, and about 1000V on the 1/2 way point on the diode array. So, plenty of HV. The low voltages and bias were correct too. But still no response from the SR-2000.

    I need to tear it apart and start cleaning tube socket pins, and do all the maintenance Jim suggested. I need to verify the speaker is good and start looking around the circuit with my O-Scope to see what is working and not.

    But the BOSS is due in any moment and he would have KITTENS seeing a giant boat anchor on my WORK DESK, so it was hidden away again. So much for today!

    The GOOD NEWS is that it didn't BLOW UP. The BAD NEWS is it didn't do much else but light up.
     
  9. WA6MHZ

    WA6MHZ Subscriber QRZ Page

    One disconcerting thing was that, after the FIRST press of the HV red button to latch it on (and then black to turn it off), I could not latch it on again. The relay would close pressing the button, but release as soon as I unpressed it. Also, the relay would not latch on or even have the light light when I put the switch to HV (HV/LV switch). SO there must be some kind of protection circuit involved in there. If I power it off, and allow it to come back on, then I can latch the HV on, but only in the LV position. Hmmmm........

    I forgot to look at the P-2000 meters, as the PS was pointed away from me, so I could access the bottom. Next time, I will watch the P-2000 meters.
     
  10. AF6LJ

    AF6LJ Ham Member QRZ Page

    This good news is indeed Good News.....
     
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