Dekabox DB655 banana connectors are loose

[cncjerry]

I have the subject box, it is in excellent condition and as near as I can tell tracks perfectly at less than .01% after many years of use.  The banana jacks are loose, I don't know if the standards changed over the years, but they look to be in great shape except the spring loaded probe masters pop out.  I started using a gold plated dual banana as a binding post but that adds a little to the resistance.  Though they look like they have a dull gold plating, I believe the connectors are an alloy, maybe with palladium and gold.  They don't look like your typical metal under the gold plating.

So I would like to replace them though I have kicked around the idea of making a threaded die for my hydraulic crimper that would allow me to tighten them up. 

Assuming I do the die trick and break them, where would I get banana jacks of the same or better caliber?


Thanks

[Vgkid]

A problem that I will soon face... the black plastic portion is falling apart(brittle with age)
similiar pomona 3750, better pomona 3770
Note the way the wire mounts to the bananna plug is completely different. On mine the wire slides into the tube that makes up the plug.

[dacman]

Does it have banana jacks on the (left) side or on the bottom?  IF they are on the bottom, then I second the 3770 (gold plated copper).  These are used in some high end standards.

[FlyingHacker]

Hi,

 I just got one of these for less than $20 USD. It is working spot on as well.

My banana jacks are also loose.

I was curious how you connected the new banana jacks to the existing wires. The old ones almost look like they have some kind of little cup on the end. I am not sure if they is crimped on, or solder on, or part of the original post. See photo.

Did you have any luck?

Thanks.

[FlyingHacker]

BTW, these DekaBoxes are amazing. The build quality is fantastic. The big knurled switches are silk smooth with perfect detents. I really could ask for a nicer design. Though mine is an ugly beige color...

[Vgkid]

Now that looks neat, mine is just a rather thick piece of stranded wire inside.

[Vgkid]

Here is the teardown of my unit.

https://www.eevblog.com/forum/testgear/esi-db655-teardown/msg678121/#msg678121

[dacman]

Looks like a soldered in barrel connector to me.

[FlyingHacker]

Looks like a soldered in barrel connector to me.

So you think if I put heat to it that little cup will come off and I will end up with the banana jack post (rear threaded part), the connected wire, and a third little cup shaped piece?

[dacman]

It doesn't look crimped on to me and I don't believe that it is machined on either.

[FlyingHacker]

It doesn't look crimped on to me and I don't believe that it is machined on either.

So you think it's soldered in?

[dacman]

It doesn't look crimped on to me and I don't believe that it is machined on either.

So you think it's soldered in?

Yes.

[FlyingHacker]

I may try swapping these connectors out. I only have some cheap Chinese posts right now. They actually are pretty decent, and I have put them into other equipment like power supplies and they work great.

So you think when I heat this up the little cup will fall off as a separate piece? Like it will result in three pieces:

1) the pos
2) the wire
3) the little cup

.??

Do you think the Pamona connectors are worth the cost? This is the type of application where I could see a benefit.

[dacman]

I don't have one of those.  I'm guessing that the cup is not part of the post.  If I had some posts that would do, then I'd use them, but if not I'd order the Pomona posts.  If the barrel or cup would not come off, then I'd consider replacing it with McMaster-Carr p/n 8965K23 (which would need a piece cut off).

[FlyingHacker]

For the record, I finally replaced the banana jacks on this. The little cups where actually part of the threaded shaft from the old banana jack. The solid wires just came out of the cups when I heated them.

I ended up doing a slight wrap around the new ends and soldering then on using a bunch of flux.

Works great.