eHam

eHam Forums => Elmers => Topic started by: AF3Y on November 09, 2012, 03:13:47 PM



Title: Power On-Off at Rig or at Power Supply?
Post by: AF3Y on November 09, 2012, 03:13:47 PM
Does it really matter?  If so, which is better?

I have always used the Power Supply switch to power up and shut down the rig, but have been told that is not good.
When I asked why it was not good, I could not get an answer besides "someone said that". ::)

I am sure I will get answers both ways, but just curious as to your opinions.

73, Gene AF3Y


Title: RE: Power On-Off at Rig or at Power Supply?
Post by: KD0REQ on November 09, 2012, 03:18:19 PM
both.

turn on: power supply, then rig

turn off:  rig, then power supply.

this way, any transients or hiccups in the regulator are NOT going to raise hob in the radio.


Title: RE: Power On-Off at Rig or at Power Supply?
Post by: WB2WIK on November 09, 2012, 03:37:54 PM
Power supplies don't go from zero to full voltage in a millisecond, nor can they turn off that way.

I leave my shack power supplies on 24/7/365 and only use the switches on the equipment.


Title: RE: Power On-Off at Rig or at Power Supply?
Post by: N4NYY on November 09, 2012, 04:12:37 PM
both.

turn on: power supply, then rig

turn off:  rig, then power supply.

this way, any transients or hiccups in the regulator are NOT going to raise hob in the radio.

Exactly


Title: RE: Power On-Off at Rig or at Power Supply?
Post by: SWMAN on November 09, 2012, 04:15:13 PM
 I know that in the owners manual for my Kenwood 570 it says to turn off the radio by its switch and not by the power supply. But it not say why not to switch from the power supply.


Title: RE: Power On-Off at Rig or at Power Supply?
Post by: K8AXW on November 09, 2012, 08:29:59 PM
It can and will be argued forever on rather a power supply "hiccups" when power is applied or shut off.  No doubt there are many who has done this "power supply first, radio left on all the time" routine all their lives.

But, why take a chance?  I would agree with REQ.



Title: RE: Power On-Off at Rig or at Power Supply?
Post by: N4NYY on November 10, 2012, 04:54:29 AM
Quote
It can and will be argued forever on rather a power supply "hiccups" when power is applied or shut off.  No doubt there are many who has done this "power supply first, radio left on all the time" routine all their lives.

I did this to my 746, and the dreaded backlight blew out. The only time I ever did it.


Title: RE: Power On-Off at Rig or at Power Supply?
Post by: AA4PB on November 10, 2012, 05:11:03 AM
I had a radio that intermittently lost all memory settings if I turned off the power supply while leaving the radio on. That's because when you turn off a power supply the voltage gradually drops as the filter capacitors discharge. Some microprocessors in the radio can have problems when their operating voltage gets too low. It is better to turn off the radio first so that the voltage goes immediatly to zero.


Title: RE: Power On-Off at Rig or at Power Supply?
Post by: KH6AQ on November 10, 2012, 07:32:42 AM
AA4PB has described the possible problem; how does the radio respond during the time the voltage is between zero and full? Strange things may happen in some circuits but the short period of time saves the radio from damage.

As a test, take your radio and raise the voltage over a period of one minute from from zero to full. Now lower the voltage over a period of one minute from full to zero.   


Title: RE: Power On-Off at Rig or at Power Supply?
Post by: W8JX on November 10, 2012, 07:39:15 AM
Quote
It can and will be argued forever on rather a power supply "hiccups" when power is applied or shut off.  No doubt there are many who has done this "power supply first, radio left on all the time" routine all their lives.

I did this to my 746, and the dreaded backlight blew out. The only time I ever did it.

I have a 100,000 mfd cap in parallel with my supply and have for many year. It softens peak demands on supply during SSB and absorbs any transit surges too. 


Title: RE: Power On-Off at Rig or at Power Supply?
Post by: K7KBN on November 10, 2012, 08:11:28 AM
I know that in the owners manual for my Kenwood 570 it says to turn off the radio by its switch and not by the power supply. But it not say why not to switch from the power supply.

"Why" is simply "because the manufacturer specifically says not to".

The manufacturer knows his product.  Failure to follow manufacturers' instructions may create problems not covered by warranty.



Title: RE: Power On-Off at Rig or at Power Supply?
Post by: KH6AQ on November 10, 2012, 08:51:16 AM
Quote
It can and will be argued forever on rather a power supply "hiccups" when power is applied or shut off.  No doubt there are many who has done this "power supply first, radio left on all the time" routine all their lives.

I did this to my 746, and the dreaded backlight blew out. The only time I ever did it.

I have a 100,000 mfd cap in parallel with my supply and have for many year. It softens peak demands on supply during SSB and absorbs any transit surges too.  

Having designed many regulated power supplies for industry I can say that adding capacitance to the output of a regulated power supply will alter the feedback loop response and can cause it to oscillate. Oscillation can be masked by the large capacitance but the power supply may still in a high stress mode (slamming the output transistors off/on and going into current limit with each cycle).

I do not recommend additional capacitance or that the existing power supply output capacitor be replaced with one having a lower ESR.


Title: RE: Power On-Off at Rig or at Power Supply?
Post by: KG6AF on November 10, 2012, 12:06:51 PM
Even if the power supply turns on and off glitchlessly, there's at least one reason to always switch the rig off while the power supply is on.  In modern rigs, the transceiver may do some housekeeping, like writing information to Flash, in the time between the rig's off button being pushed and the power being turned off.  If you turn off the power supply first, the rig may not have the time to do this housekeeping before power disappears.  Best case, some of the rig's state isn't saved, and you have to re-enter information when the rig is next turned on; worst case, the state of the rig is scrambled, and you have a repair job to do.  I know that the K3 manual has a warning that the rig should be turned off before the power supply.





Title: RE: Power On-Off at Rig or at Power Supply?
Post by: NO2A on November 10, 2012, 01:32:55 PM
I think this is similiar to why you don`t start a generator with a load on it.


Title: RE: Power On-Off at Rig or at Power Supply?
Post by: KE3WD on November 10, 2012, 03:43:57 PM
Modern rigs with internal processors should be turned both on and off via the rig's intended power switch.  There is both a bootup routine to consider here as well as a power down routine.  Many of these rigs, the power switch is in software rather than an old design switch that simply cuts power at the base level. 

Of course, you can turn the Power Supply on and off as well, just be sure to turn it on first, then power the rig, and at power down, the opposite applies, turn off the rig first, then turn of the Power Supply.

Experimenting won't prove much of anything, for these routines happen fairly quickly and you are just playing the odds.  Most times, the design of the rig is such that it can survive a sudden power cut, but there's that one time...

Don't risk scrambling the bits. 

73


Title: RE: Power On-Off at Rig or at Power Supply?
Post by: VA3KBC on November 10, 2012, 04:13:34 PM
My TS590 manual says that I can turn off the transceiver by turning off the power supply.
I can skip turning the radio off by it's own power switch.

I have the TS590, DX Enginerring antenna switcher, FT1900 two meter radio, Daiwa CN-801 SWR & Power meter light all powered by the Astron RS-35M power supply.
I just tunr off one switch.
DJ


Title: RE: Power On-Off at Rig or at Power Supply?
Post by: K0IZ on November 10, 2012, 06:45:08 PM
My K3 is supposed to be turned on after power supply is on, and turned off before power supply is off.

 Per Elecraft: To ensure correct save of operating parameters, turn the K3 off before turning the power supply off.


Title: RE: Power On-Off at Rig or at Power Supply?
Post by: WD4CHP on November 11, 2012, 05:59:37 AM
I keep my power supply off when not in use.

This keeps my power consumption down as the supply uses power even when nothing is being used.

(This also applies to wallwarts)

I turn the supply on and wait a couple of minutes for it to stabilize then turn the rig on.

I turn the rig off first then the power supply.

Go Green!


Title: RE: Power On-Off at Rig or at Power Supply?
Post by: AF3Y on November 11, 2012, 06:57:39 AM
OK.... ;D  I'm a believer.  Almost all say use the switch on the rig instead of the PS. 

I will do it that way from now on. Thanks for all the comments guys! 

73, Gene AF3Y


Title: RE: Power On-Off at Rig or at Power Supply?
Post by: NR4C on November 14, 2012, 06:30:50 AM
Well, in some cases it depends on the radio.

Older type radios were probably more tolerant of this practice.  But, modern computer controlled radios don't like to have the power cord pulled.  Radios like Elecrafts' K3 or KX3 and many others are more like computers than radios, and when shutdown properly, store many operating parameters to nonvolatile memory at the time of shutdown, so that when powered on again, it is in the same configuration as it was when last used.  Many parameters values are kept so that as you change bands, the filter settings, mode, NR/NB and many others setttings are saved so that when you change back to that band, the radio is just like you left it.  Same for turning the radio off and then back on.  If you just pull the plug, none of this is saved, and it looks like it did the last time it was saved.  This is true for many internal parameters as well, so it's not a good idea to just pull the plug on a radio like this.

Your dad's old TS-520S may not care, and some would say you're saving wear and tear on the switch.


...bill  nr4c


Title: RE: Power On-Off at Rig or at Power Supply?
Post by: KG6YV on November 14, 2012, 04:48:18 PM
It is NOT a good idea to use the power supply on/off and not turn the rig off on the front panel for many of the ultra new rigs.

Any radio like the yaesu's (FT-2000, 950, 5000 and 9000) have very orderly power sequencing built into
the radio to make sure that the internal firmware and software come up in the correct sequence.  They don't necessarily have internal software code that looks at everything and preserves integrity if you do not use the radio's power button to sequence events.... Don't be surprised if something gets trashed if you don't follow
the correct sequence.   

Don't own and ICOM or Kenwood so I don't know how they would react to this.




Title: RE: Power On-Off at Rig or at Power Supply?
Post by: W4VR on November 15, 2012, 08:58:08 AM
I think this is similiar to why you don`t start a generator with a load on it.

Precisely.  I always turn off the radio before I turn off the power supply...and turn on the power supply before I turn the radio on.  I use switching power supplies, so I don't leave them on 24/7.


Title: RE: Power On-Off at Rig or at Power Supply?
Post by: N6AJR on November 15, 2012, 11:24:19 AM
lug everything into a 5 or 6 hole zip strip.  then turn on everything with it.  after replacing the on off and stand by switch ( now made of unobtainum) on a ft 101, you learn its easy and cheap to replace the zip strip when the switch fails as opposed to changing the switch on the radios.


Title: RE: Power On-Off at Rig or at Power Supply?
Post by: K2OWK on November 15, 2012, 03:34:04 PM
I have been in Ham radio and electronics for more then 50 years. It has always been good practice to turn the power supply on first then the piece of electronic equipment, and reverse the order for shut off. This also holds  for plugging in wall warts for charging HTs, Cell phones and rechargeable electronic equipment. Plug the charger in first then the the equipment and reverse the order for removal. Modern equipment has many types of protective circuitry, but why take a chance. The reason for this order power switching is to avoid back EMF which can produce a voltage spike many times the amount of the set voltage. I will always use the power supply on equipment on, and equipment off power supply off mode of operation.

73s

K2OWK