[Amps] LK550 ALO/Meter board interconnect - anyone know what the manufacturer or part/type of the two 6-pin nylon connectors that mate with J1/J2 on the ALO/Meter board?

Wed Nov 1 23:22:23 EDT 2023

Basically yes.  12volts comes up from the 12v supply and feeds the ALO board.  If all is good it sends -2v to the relay.  The ALO board interrupts that in a fault so just bypass it to the relay.  

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On Wednesday, November 1, 2023, 6:55 PM, wb0gaz at yahoo.com <wb0gaz at yahoo.com> wrote:

 So remove 12V going into the ALO/Meter board (that came from the xmt/stby switch), leave the two meters and associated resistors in place (they're passive), and send the now-removed 12V that went to the ALO/Meter board back to the relay stuff... Sound right?

     On Wednesday, November 1, 2023 at 04:50:42 PM MDT, gudguyham at aol.com <gudguyham at aol.com> wrote:  

 The board trip simply cuts out the 12v to the antenna relay board.  I just cut the 12v line and connect it to the line out to the relay. End of story.  

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On Wednesday, November 1, 2023, 6:33 PM, wb0gaz at yahoo.com <wb0gaz at yahoo.com> wrote:

Thanks! That is consistent with my thought - with 3-500Z tubes, there's nothing to be gained as long as the op pays attention...

If I can identify the PCB-end connectors in use, that will reduce the hassle of pulling them, but your comment adds fodder to the idea that the board wouldn't likely be of future use anyway...

     On Wednesday, November 1, 2023 at 04:26:44 PM MDT, gudguyham at aol.com <gudguyham at aol.com> wrote:  

 Dave, the ALO boards on these amps are for the most part worthless.  They don’t trip on the important factors anyway.  When they go bad I usually just bypass them.  Not worth the effort to repair them unless it’s something obvious.  The LK550 HD as 3 3-500 tubes.  As long as your meters are working properly you don’t need any trip circuits.  With the LK800 amps the ALO board has a timer on it to hold off RF until the cathodes warm up, there it’s a must!  But even still I don’t believe it trips on grid overload.  If you are concerned about real protection most tubes benefit from a simple grid trip circuit which is a lot less complicated than the ALO board.  Some ALO boards do have grid shunt series resistors that will occasionally open up with tube arcs.  They usually can be seen as bad when inspected closely. 

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On Wednesday, November 1, 2023, 5:29 PM, wb0gaz via Amps <amps at contesting.com> wrote:

 Thanks (Dave) for insight on the panel meters.

Arriving to the point (on LK550) that the ALO/Meter board is suspect - either was damaged or caused damage in it's prior life. Several traces handling 12V path were badly overheated, one to the point of destruction, and the board (with a couple of previously added jumpers to bypass two of the smoked traces) is still dragging the 12V DC control power supply (simple half-wave rectified off the low voltage transformer) down to near zero when amplifier is enabled (XMIT on the XMIT/STBY switch.)

Now intend to delete ALO/Meter and rewire as if it were a LK500 or other model without ALO/Meter (hence why I wanted to understand the nature of the two panel meters.)

Next step is to find pair of nylon 6-pin connectors (equal to what are currently on the ALO/Meter board); they are physically polarized and a search through digikey hasn't found anything equivalent so far. Although could remove the connectors from the (suspect) ALO/Meter board, would rather set it aside as-is for now and source replacement connectors (on the PCB, the two connector housing are female, and the (6) pins are male.) My supply of pins doesn't include any that are the same dimension as the one used on the PCB (else I'd just stuff equivalent pins into the needed positions on the end-of-wire connectors and call it a day.)

Thanks again for the hand-holding through this saga!

Dave

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