HP 6627a gummy / hard wire covering

[GRFixedGear]

Folks,

Doing the Rifa cap replacements on my 6627a with a 3420Axxxxxxx serial number. Unit had already been treated for fair amount of dust collected inside as well as a frozen cooling fan. As I got into the board removal for the Caps, I recognized that the vinyl?? coating around the wires to/from the transformer and power switch was VERY gummy and VERY rigid. I've managed to strip that stuff off all the wires of any appreciable length, and the individual wires inside seem stiff but not unduly so. I'm assuming those wires are best covered with something for chafe-resistance and additional electrical insulation. It would be easy to wrap them back up with split woven wire loom, but that may not give the full electrical insulation the designers expected.

Any suggestions for what to use in this case?

Thanks
Jason

[jpanhalt]

Are the wires solid bare, enameled, or stranded?   That is, was the "vinyl" a  secondary insulation.  What gauge are the wires?  Are they soldered at each end?  If that's the case, the easiest solution would be to replace them.  I usually use thin wall, Teflon spaghetti tubing for insulation, but other things like heat shrink will also work.

[GRFixedGear]

jpanhalt,

All of the wires in question have primary insulation on them. The "vinyl" would definitely have been secondary or just chafe protection or maybe just bundling things together so that they can be routed nicely. The lid of this supply has two of the output boards on it and folds open while still connected making it very nice to service, so bundling the wires to allow for that to open may also have been the goal.

Most of the wiring looks to be 18AWG or so. Maybe some of it is smaller like 22AWG. All of the wires have crimped on terminals on the end, if not a big connector on them. Connections between the transformer and the individual output boards have big, right-angle, female QD terminals on the one end, and 4 or 8 pin connectors on the other end.

Heat shrink would be more attractive if the terminals / connectors didnt make getting it installed difficult. Hence that attractive points of the woven split loom.

Thanks!
Jason

[HalFoster]

That is common to just about all of that type and vintage of HP power supplies.  I don't know what the cause is but it is nasty.  I usually just cut it off, clean the wires, and us small tie wraps to re-bundle.  Or, if I'm feeling bored and retro, break out the lacing cord.

Hal