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Just purchased a henry 2k2 1967 vintage

Discussion in 'Amateur Radio Amplifiers' started by KE4AMQ, Mar 14, 2021.

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  1. KE4AMQ

    KE4AMQ Ham Member QRZ Page

    The amp did not power up when i got it, I replaced the bleeder resistors and now it powers up but pegs the amp meter and I have nothing on the high voltage meter. Then it trips the curcuit breaker in the amp. I tried to take the tubes out and tried it that way did the same thing. I did change a couple of the high voltage wires with new high voltage wires. all lights on the amp work, oh by the way its wired for 240 and I dont have a 240 variac, I do have one for 120volt. I was thinking of wiring it for 120 and try it that way to see what happens. This is a great group with alot of smart guys maybe one of you had this happen and could steer me in the right direction. another thing to add is when it does power up the tubes dont light at all. Thanks in advance
    Fred ke4amq
     
  2. KE4AMQ

    KE4AMQ Ham Member QRZ Page

    The amp did not power up when i got it, I replaced the bleeder resistors and now it powers up but pegs the amp meter and I have nothing on the high voltage meter. Then it trips the curcuit breaker in the amp. I tried to take the tubes out and tried it that way did the same thing. I did change a couple of the high voltage wires with new high voltage wires. all lights on the amp work, oh by the way its wired for 240 and I dont have a 240 variac, I do have one for 120volt. I was thinking of wiring it for 120 and try it that way to see what happens. This is a great group with alot of smart guys maybe one of you had this happen and could steer me in the right direction. another thing to add is when it does power up the tubes dont light at all. Thanks in advance
    Fred ke4amq
     
  3. KA0HCP

    KA0HCP XML Subscriber QRZ Page

    1. Have you checked the filament/heater circuit for proper voltage at each tube position?
    2. Does the meter show proper HV value?

    -Take things one step at a time. Work from simplest to complex possible problem.
     
    KE4AMQ likes this.
  4. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    Why would you change the bleeder resistors? Unless one or more failed, they would be the last thing in the world I'd replace, and the amp would have HV with or without them, although if this model has choke input as many older Henry amps did, the HV would be way too high without the bleeders.
    If it trips the breaker, how do the lights on the amp work?

    If it trips the breaker without tubes installed, either something is miswired or something is shorted (such as a rectifier or filter capacitor, or possibly a pinched wire or loose hardware shorting B+ to the chassis). A common point of failure with older Henry amps having choke input is the capacitor across the choke, and if that fails it will blow the breaker also.
     
  5. KE4AMQ

    KE4AMQ Ham Member QRZ Page

    well I had one of these amps before and no hv if the bleeders are out and one read wrong value so i changed it they are 20k and one showed 14k the other two showed 20k
     
  6. KE4AMQ

    KE4AMQ Ham Member QRZ Page

    The circuit breaker I believe is for just the high voltage and dont work anything on the low voltage side of things
     
  7. KE4AMQ

    KE4AMQ Ham Member QRZ Page

    it dont show any hv
     
  8. N6UH

    N6UH Ham Member QRZ Page

    I rebuilt an original 2K from 63/4 recently. I would guess they are similar and has the choke based power supply? If it has been standing unused you will probably find either the transformer or choke or both are toast. Mine was the transformer which made an interesting hissing and gurgling noise as I brought it up on the variac. The choke's resonating capacitor had been leaking too. I ended up gutting it and starting again so I have the filter capacitor, choke and transformer for the rectifiers if you need any of them. With high voltage kit this old it's probably only a matter of time before it fails anyway
    If the meter circuit is the same as the model I have there's a fuse in the multi-meter circuit which maybe OC so no HV indicated. Do you have the equipment to measure the voltage off the power supply safely and is there voltage present?
    There are also a couple of interlock switches one on the door and one on the top cover.
     
    K0UO likes this.
  9. W1QJ

    W1QJ Ham Member QRZ Page

    If you have no tubes in the amp and the plate meter pegs then that’s telling you that there is a path to ground for the plate voltage. Something is pulling the the B+ case to ground. The first thing you want to do is check the transformer for internal shorts to ground. Take your two or three secondary leads and ohm them to ground or back to the primary. Check anything and everything that could form a path to ground from B+. If you have a Variac you could disconnect the secondary wires from the rectifier and bring line voltage up on the transformer, watch for the plate meter or grid meter to move. It shouldn’t!
     
  10. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    It should, according to the schematic. The "tap" for the smaller transformer comes from after one of the 15A circuit breakers. The smaller transformer (LV) also has its own 3A fuse which would protect those circuits in the event of a fault that doesn't cause the 15A breaker to open, and there's still another 3A glass fuse for the blower and relay circuits (those are "inside" behind the power supply door). There's still another 1-1/2 A fuse in series with the plate current meter.
    henry 2k-2.PNG

    But if for some reason the main breakers open, that should shut everything off -- unless someone has re-wired things after the originally factory wiring.

    If one of the bleeders measured 14K and the other two measured 20K, that should not have really changed anything except to make the bleeders dissipate more power and get hotter. But wouldn't change the way the amp operates. If one resistor opens entirely, the HV should soar to about 4500V and that could be harmful, although the 20uF filter cap is an oil-filled one rated 5kV and the 20K resistors are rated 100W each, so such a failure may not actually result in any damage assuming all the components are original or replaced by ones rated same as original.

    It's unusual for wirewound resistors like the original bleeders to drift in value: Usually, they're either the original value or they open altogether when the wire burns out.:p
     

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