Kenwood PS-430 running hot

[Supspt454]

I noticed that my power supply is getting above warm to touch. It's not hot enough to cook by any means, but I'm sure it's warmer then it needs to be with my 440s in receive only. The fan hasn't kicked on yet, I've only had it up and running but for a few days. But if something is wrong with the fan, I would like to repair that soon. Or install a switch. Any thoughts?

Thanks

 

[TonyV225]

Sometimes it's hard to say with both over radios some do get pretty warm as a matter of fact some newer radios get warm I know some people as myself used to just put an extra fan blowing behind them.

 

[wavrider]

TONY nailed it, small fan, Wally world type 5 or 6 inch behind it and solves the problem of heat.

I use one on all my rigs, never an over heating problem. The TS-440 is noted to run hot due to the design of the thermal sensing circuit, so instead of tearing it apart and modding it just put a fan on it and go to making contacts.

 

[k3cfc]

I think he was talking about warm ps 430 ( power supply ) not a ts 440 radio.

Just my observation from what i read.

 

[N6MYA]

RE: PS-430 getting hot

I use a PS-430 to power both an ICOM IC-271A two meter radio and an ICOM IC-471A 70cm radio at the same time for working satellites. The 471A is in amost continual transmit and the 271A is of course in continual receive. The power supply only becomes warm in these conditions and the fan does not come on.

A couple things to check if you can. 1) Check the amount of current drawn by the TS-440 in receive, it should be OK. 2) Check that the fan that is built into the PS actually works by jumpering it directly to 12VDC. 3) Open the power supply and make sure it is clean and free of dirt and dust accumulation.

If still a problem, i have a schematic for the unit that i can e-mail to you.

73 and GL

Paul
N6MYA

 

[wavrider]

I think he was talking about warm ps 430 ( power supply ) not a ts 440 radio.

Just my observation from what i read.

You read it correct. I just added that I put a small fan on my ts-440 when I use it to keep it cooler than the internal fan.

The PS-50 has no issues on providing the voltage/current for the TS-440

 

[Shockwave]

The PS-430 always ran hot because the pass transistors have significant voltage across them in receive. That's why they offered the heavy duty PS-50. The PS-430 can sometimes overheat and short the pass transistors. Thankfully, Kenwood engineers placed a crowbar circuit in the output stage of this power supply so that a power supply failure will not destroy all of the equipment connected to it. I would check the voltage rating of the internal fan and if it is 12 volts, consider wiring it directly to the output terminals so the fan is always on with the supply.

Alternately, if you can locate the thermistor on the heatsink that controls the fan, you could achieve the same result by either clipping one wire or shorting the two together. Which one will work depends on if the circuit uses a negative or positive temperature coefficient. This modification will also require that the existing driver transistor is still functional where the first option would bypass it altogether.