Epiphone Models with Circuit Board Wiring Modules

[Lefty Bill]

I don't have an Epiphone Ultra II, so the only reference I have to the circuit boards and cable connectors would be the excellent pics Rastus took recently..

Link to Rastus' Ultra II board pics

http://forum.gibson.com/index.php?/topic/82302-les-paul-ultra-2/page__view__findpost__p__1126462

 

As far as new replacement cable connectors go, here are some comments previously posted..

Link to my reply about mini cable connectors

http://forum.gibson.com/index.php?/topic/81683-quick-connertor/page__view__findpost__p__1117702

 

I can see from the pics shown in the other Ultra II thread that servicing those circuit boards for repairs or upgrading pots, will present some challenges to those who may not be experienced in electronic equipment repair.

 

I dunno what Epiphone's position on circuit board failures is (scratchy pots etc), but returning a guitar to an authorized repair center for repair may be more time consuming than many players want to endure.

 

Until some kind member posts the actual dimensions of the connectors or other parts, anyone who may be attempting to locate replacement parts will be trying different solutions, some which may work or not work.

At least several forum members can probably locate sources for the correct parts if someone posts the actual dimensions of the parts.

I've seen the same types of connectors used in many types of electronic equipment, but can't determine the specific parts from a picture.

 

The board-mount style of the pots use terminals which are bent to penetrate holes in the printed circuit board, which makes them more difficult to replace than common eyelet terminal pots.

Overheating or excessive stress/pulling to remove those terminals in the PCB can cause damage to the foil traces on the board, which will then need to be repaired to restore the board's proper operating condition.

A common repair practice is to carefully cut the terminals, remove the part (pot in this instance) then unsolder each terminal separately, which is generally easier than cleanly desoldering all the terminals to remove the faulty part intact.

Modern boards are fairly easily damaged if the proper tools and methods aren't utilized.

 

The particular style of pots isn't new, so replacement parts can be found at various electronic suppliers.. although until a seller lists them as "Ultra II replacement pots", the actual dimensions of the original pots will need to be measured and carefully compared to new part specs in catalogs, for example.

 

Having a fairly accurate measuring device such as a caliper will generally be the best method of measuring dimensions of pots and cable connectors.. dimensions are typically metric for most electronic components originating in China and numerous other regions.

Most inexpensive calipers will be sufficient.. a dial caliper is adequate, but the digital calipers are more versatile because they have inch and metric capability and convert either measurement instantly with a button.

 

In addition to selecting the desired pot resistance and taper specifications, the various physical dimensions needed to be matched will be the shaft length (split-shaft push-on knob style), bushing diameter and length, body diameter, and the spacing of the terminals.

The bushing is the area where the threads for the nut are located.

 

Suppliers will vary depending upon location, but several good US suppliers have detailed specs shown in their catalogs (DigiKey, Mouser, Allied etc) while other suppliers can also generally provide good parts, such as Jameco Electronics.

 

I can see that the latest practice of using circuit boards (instead of point-to-point wiring) will present new difficulties for owners who previously had performed their own repairs/modifications, but approaching parts replacement carefully, and possibly requiring a few new tools (yippeee!), many owners shouldn't have a great deal of difficulty working on the newer modular type guitar wiring assemblies.

 

Bill