HP 3455A, 3456A, etc. Banana Jack (Binding Post) Replacement - Possible?

[radiolabworks]

I did a general search through the Test Equipment section for this topic and came up dry.

I have a couple of old HP 3455A's that have broken Banana Jack ABS outside barrels nuts.  Removing as a unit should not be an issue, but has anyone ever been able to remove one of the individual jacks from the ABS mounting frame?  Each jack appears to be srewed in, but my guess is HP probably applied a locking glue to them and thus made them impossible to replace except as a whole unit of all five binding posts.  Naturally even trying to unscrew the upper portion of the binding post you get stopped once the post wire entry hole is cleared.   

I'm trying not to force anything as I  don't want to do more damage.

Anyone played with these?

Thanks,
Don - Radio Lab Works

[bob91343]

They may be held in by nuts on the back of the panel.

[radiolabworks]

I already had it open and there are NO nuts.  HP used a ABS mount behind the panel that is threaded to accept the thread of the binding post (which are also ABS).  So it's ABS screwed into ABS.  I can see signs of a dried liquid on the rear, so my guess is they used a glue as well.  The glue makes sense as you wouldn't want them turning out.

Update:  Using a pliers with a hard rubber protection on the grip teeth I was able to screw off the two damaged binding post tops.  They appear to flute out the ends of the metal contact portion of the jacks to keep them from normally being screwed off.  With a little force the damaged ABS ends will thread off.  I did the same to remove some good ones off a donor DMM and screwing them back on was easier (naturally).  This is not a procedure for the meek    Taking them off requires turning them off a little at a time and keeping the top portion of the binding post straight as you do it.  You don't want to mess up the threads, except for that flanged out end section which is essentially getting die threaded via backing the damaged binding post top off. 

Here is a picture of the final swap.   My working 3455A is on the bottom with two replacement binding post ends and the donor 3455A is on top.



If you want to see what was removed from the lower DMM.  Here they are.  One only had the metal insert left and none of the upper ABS portion of the binding post remained.  The second wasn't that bad, only the red plastic insert was missing on that one.



Don

[bob91343]

I would love to have that donor 3455A.  Mine is dead and I need some parts.  PM me if you are interested in getting rid of any or all of it.

[radiolabworks]

Addendum Number II:

To prevent damage to the ABS top on those binding posts I used a short piece of 300psi Air Hose that slide perfectly over the end of the top.  Here is a picture of me installing a replacement top, removed from the rear terminals using the same method, with the hose slide on and my pliers slowly turning it back on.  Using a marker you can mark a line on the red plastic insert to verify the cap is turning with the pliers and not just slipping around the top.  Once you hit the point beyond the ferreled end it will turn on with your finger and the hose can be pulled off.

This is my HP 3455A Black Faced version.  So finding replacement binding post tops is even harder than most other HP equipment.  I took the black tops from the rear posts and will eventual replace those with the gray versions.

 

[Oldtestgear]

I have a few of these assemblies  for the 3456A that I bought (used) a while ago. All are in good used condition but are located in the UK. May be worth investigating if no one else can help.

Phil