Power cables getting really hot

[dubo2319]

Hi Guys
I wonder if you can help me.
I have got a Kenwood TS870 for last couple of days, and I have noticed that after I use radio with full power on SSB (70w) and FM (60w) my power cables getting really hot.

Also I do own Yaesu FT450d, and when using this radio with the same power supply cables stay cool.
Any help will much appreciated.
Thank you.

[26TM944]

Both the Yaesu and Kenwood needs around 20amps at full power - which at 12v is quiet high - however you say the same cable only gets warm with the Kenwood connected?

Are the cable runs the same? Are they coiled up anywhere? Is the Kenwood OK? Full power? Do you have a current meter or does the PSU so you can see what is happening? Can you lower the Kenwood to say 10w - do you get the cables warming up then?

My old ICOM 7000 never heated it's cables at all during 100w SSB long QSOs, the radio yes, but never the supply cables.

It might be a poor connection at the radio causing a voltage drop which is raising the current demand - but you'll need a meter to prove this. Or of course a fault.

Oh one question is the cable the genuine one?

73 Steve

[Admiral]

Make your mind up, are they getting really hot or really warm?

[dubo2319]

Hi Steve
Thank you for the reply.
I have just bought this radio on the ebay, and the guy told me that he never had such a problem.
The power cables are two different ones, and the PSU is the same which is 25A.
I will check the cable as is coiled up little bit behind my desk and I will check the connection plug of course as suggested.
I do not own a current meter but I will try to source one.
Cable doesn't look genuine, however the gauge of the cable looks fine similar to my Yeasu cables.
I will check the radio with 10W and see if they will warm up sounds a such a good idea.
The other think I have noticed as well is the power output drop, when mic is keyed on the FM I am getting 60W and than drops to 50w and again after a split second is coming back to 60W.
Thank you for your help.
Adam

[dubo2319]

Make your mind up, are they getting really hot or really warm?

Hi I will say they getting really hot.
Thank you.

[Trog]

Hello dubo. Without wanting to state what could be obvious, you say the power cable looks fine and similar to your Yaesu cables but if the cable is not the original, it could be that this particular wire/cable has a much thinner core than is needed. Some cables look thick but only because the insulation is thick. The copper core could be thinner than expected and, if this is the case, it will warm up if the current is high. Can you not try using a larger diameter cable or even temporarily 'double up' the cable you are using? If it's not the cable then there's a fault with the rig (obviousy).

[kr0ne]

Buy bigger cables...

[dubo2319]

Hello dubo. Without wanting to state what could be obvious, you say the power cable looks fine and similar to your Yaesu cables but if the cable is not the original, it could be that this particular wire/cable has a much thinner core than is needed. Some cables look thick but only because the insulation is thick. The copper core could be thinner than expected and, if this is the case, it will warm up if the current is high. Can you not try using a larger diameter cable or even temporarily 'double up' the cable you are using? If it's not the cable then there's a fault with the rig (obviousy).

Thank you for your suggestion, I will definitely try this.
Adam

[DummyLoad]

Adam
If your power cable has inline fuses (hopefully it has) check that the fuses themselves and the fuseholder contacts are clean and making good contact.
Poor contacts in inline fuseholders can be the cause of intermittent power variations due to voltage drop.

[Transwarp]

1. Don't have the radio's power lead coiled or tied up in hoop or bundle.
2. Sensible length of the radio's power cable, not 5 meters long if it doesn't need to be.
3. Cables fuse holders are making good connections with the fuses and are tight.
4. Good solid connection of the radio's power lead to the PSU output terminals.
5. If the radio has a short power cable tail coming from it with a connector on to join up to the rest of it's power cable, make sure this is in good
condition and is a firm fit together.

If the radio's power cable is not a genuine one I'd replace it anyway, or make a new one with good quality cable and fuse holders. My power cable for my FT-450D is still in the box not used as I made up a custom one for shack use.

[dubo2319]

Hi guys.
Thank you for all your help.
This is what caused the heating problem.
Now I am looking to replace the cables as this are poorly made.
Adam
All the best 73's

[spynappels]

It may be worth looking at putting some PowerPole connectors on, get the 45A rated ones for on the power supply and whatever ones best match the rating of the radio on the radio end. They make swapping rigs much easier and will easily cope with the currents you're drawing.

[Trog]

By the picture, it's obvious that those connectors cannot cope with the current (and/or there's a loose connection in there somewhere).