Change That Cord

[leonski]

I'm educating myself as I go along so here goes....

I'm putting a new cord in an Ancient Kenwood KA-7100 integrated amp.   This is all of about 60x2 and has a couple outlets with maybe a 200 watt rating.

But the cord?   Getting old and 'stiff' so I'm scared of insulation breakdown.   

Here's what I did.....

Bought a 15 foot Extension Cord.    I LOOKED for SPT-2 wire.   This has a thicker insulation than SPT-1 and can be found in 18ga or 16ga sizes.     Maybe thicker?

I bought the 16ga for this project.   Maybe 4$ or so?

Cut off the plug end with about 7 feet of cord.   The ORIGINAL plug was NON-polarized.   Both blades were the same width and so would plug in Either Way.

But the cord DID have a ridge on one conductor which might mean THIS should be the Neutral wire (Thanks DY)   This way I now have a properly wired and secure

Polarized plug.     I'll solder the ridged wire to where the ridged wire is NOW attached.      Should be ok, right?    

Next Hurdle is the strain relief.    I see they are not common and simply not at home stores or Best or anywhere else.    Digikey may have them but I found 'em at

WE-Supply, here in SanDiego.    Unfortunately they come in 15 (yep....Fifteen) sizes.    I'm only interested in those sizes for wire about 0.150" X 0.300"  so that leaves

me with 2 choices...    The choices are based on panel thickness.    Either about 1/16" = .0625"      OR   about 1/10", which they call .098"  

i'll go to work area and measure (by micrometer) panel thickness and get them.    The are cheap.   Maybe 0.20$ each and you buy 10 at a time.  

I have found that taking things 1 step at a time, I can do things which I didn't think I could do.      I may have to enlarge the chassis hole, but I'm ready with a vacuum

and a magnet and tape.     Can't afford Any metal chips getting into the works.

[adaboy]

You could have performed a megger test to see if the insulation was still adequate. But.... It's more fun to change it😊

[leonski]

I've asked several electricians about a megger to nothing but blank looks.

I think we had one at work to check the grounding of certain machines.

I even had to buy my own amp-clamp. Besides? Upgrade from 18 to 16 is nothing but to the good.

Next up? New PS caps.

I think the Polarized plug...to a newer NEC level is also to the good.

[405x5]

Jan 4, 2021 20:07:51 GMT -5 leonski said:

I'm educating myself as I go along so here goes....

I'm putting a new cord in an Ancient Kenwood KA-7100 integrated amp.   This is all of about 60x2 and has a couple outlets with maybe a 200 watt rating.

But the cord?   Getting old and 'stiff' so I'm scared of insulation breakdown.   

Here's what I did.....

Bought a 15 foot Extension Cord.    I LOOKED for SPT-2 wire.   This has a thicker insulation than SPT-1 and can be found in 18ga or 16ga sizes.     Maybe thicker?

I bought the 16ga for this project.   Maybe 4$ or so?

Cut off the plug end with about 7 feet of cord.   The ORIGINAL plug was NON-polarized.   Both blades were the same width and so would plug in Either Way.

But the cord DID have a ridge on one conductor which might mean THIS should be the Neutral wire (Thanks DY)   This way I now have a properly wired and secure

Polarized plug.     I'll solder the ridged wire to where the ridged wire is NOW attached.      Should be ok, right?    

Next Hurdle is the strain relief.    I see they are not common and simply not at home stores or Best or anywhere else.    Digikey may have them but I found 'em at

WE-Supply, here in SanDiego.    Unfortunately they come in 15 (yep....Fifteen) sizes.    I'm only interested in those sizes for wire about 0.150" X 0.300"  so that leaves

me with 2 choices...    The choices are based on panel thickness.    Either about 1/16" = .0625"      OR   about 1/10", which they call .098"  

i'll go to work area and measure (by micrometer) panel thickness and get them.    The are cheap.   Maybe 0.20$ each and you buy 10 at a time.  

I have found that taking things 1 step at a time, I can do things which I didn't think I could do.      I may have to enlarge the chassis hole, but I'm ready with a vacuum

and a magnet and tape.     Can't afford Any metal chips getting into the works.

You’re over thinking this.
A few electrical tape wraps will stop it from pulling through, or knotted (1) internally if you’ve got room.
This is no high powered unit with the power cord being any kind of headache.

[DYohn]

Only ex-military types like me know what a meggar test is. Most electricians call it simply insulation testing or hi-pot testing.

[leonski]

405?
I thought of a couple alternatives but do not want Any chance of the cord 'rubbing thru' on the metal hold.
Maybe if I could find a proper grommet?
Don't overlook the new Polarized plug.....

[DYohn]

I usually use these. Thety are called cable strain reliefs

[leonski]

Yes exactly.
But the model # you get depeends on the exact cord and thickness of the panel....

For example? Philmore #65-1015 is made to fit SPT-2 wire. This is usually in either 16-2 or 18-2 with 300v insulation. This is the CHEAP indoor cords at the home stores.
I found a 15 footer for about 4$ and cut off 7 feet including the polarized plug. I'm just going to drill a 1/2" hole and whittle to fit. I've already run a test and was successful.
Tight fit which is fine by me.

Hilmore makes a total of 15 different models of JUST what DY shows. Good all the way from SJT-12/3 to SPT-1, you should be able to replace nearly any cord in any fixed-cord
applliance or gear.
I wish I had the chassis punch used to make the exact hole......

I spent 2$ for 10 of 'em.....so I can experiment on 1, use 1 and give 2 with the amp I'm selling IF the buyer wantt to go thru the hell I'm going thru.

I was being 'smart' when I mentioned grommets. they'd rub thru and you'd end up with tie wraps trying to prevent pull-thru. Marginal solution.