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KPA500 fan won't shut off

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jerry-5

KPA500 fan won't shut off

After yesterdays contest, I noticed this morning that the KPA500 fan was
still running at a high speed even though the amp had been turned off
all night by using the front "on" button. The only way the fan stops
running is if I turn the amp on with the front switch or if I shut the
amp off by using the rear on/off switch. Menu setting for Fan is set to
normal. Any ideas?

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Bill K9YEQ

Re: KPA500 fan won't shut off

Try reloading your saved firmware. Could be an internal error which can happen. Reloading firmware, preferably one you have saved will correct the error.

72 & 73,
Bill
K9YEQ
FT’er for K2, KX1, KX3, KXPA100, KAT500, W2, etc.

-----Original Message-----
From: [hidden email] <[hidden email]> On Behalf Of jerry
Sent: Sunday, July 14, 2019 1:23 PM
To: [hidden email]
Subject: [Elecraft] KPA500 fan won't shut off

After yesterdays contest, I noticed this morning that the KPA500 fan was still running at a high speed even though the amp had been turned off all night by using the front "on" button. The only way the fan stops running is if I turn the amp on with the front switch or if I shut the amp off by using the rear on/off switch. Menu setting for Fan is set to normal. Any ideas?

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Re: KPA500 fan won't shut off

In reply to this post by jerry-5

That means the power is not shutting off. We bleed off the capacitor charge through the fan at front panel shutdown, which is why you hear the fan run for normally a short time.
Turn off the KPA using the rear pane switch and call tech support in the morning. They need to look into this one.

73!
Jack, W6FB

> On Jul 14, 2019, at 11:22 AM, jerry <[hidden email]> wrote:
>
> After yesterdays contest, I noticed this morning that the KPA500 fan was still running at a high speed even though the amp had been turned off all night by using the front "on" button. The only way the fan stops running is if I turn the amp on with the front switch or if I shut the amp off by using the rear on/off switch. Menu setting for Fan is set to normal. Any ideas?
>
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k4vd

Re: KPA500 fan won't shut off

Jerry:

Maybe clarify. I think Jack's concern is that your fan was running even
with the power off. That's not the case, right? The fan just came back on
full when you turned the power back on?

Try Menu, scroll down to FAN CTL and make sure that say NOR. If it has a
number instead, you somehow accidentally set the fan on at that speed. Just
use the down arrows to get back to NOR. This is all done on the front panel
of the KPA500. Hope it helps.

73,
Kev N4TT

On Sun, Jul 14, 2019 at 2:38 PM Jack Brindle via Elecraft <
[hidden email]> wrote:

> That means the power is not shutting off. We bleed off the capacitor
> charge through the fan at front panel shutdown, which is why you hear the
> fan run for normally a short time.
> Turn off the KPA using the rear pane switch and call tech support in the
> morning. They need to look into this one.
>
> 73!
> Jack, W6FB
>
>
> > On Jul 14, 2019, at 11:22 AM, jerry <[hidden email]> wrote:
> >
> > After yesterdays contest, I noticed this morning that the KPA500 fan was
> still running at a high speed even though the amp had been turned off all
> night by using the front "on" button. The only way the fan stops running
> is if I turn the amp on with the front switch or if I shut the amp off by
> using the rear on/off switch. Menu setting for Fan is set to normal. Any
> ideas?
> >
> > ______________________________________________________________
> > Elecraft mailing list
> > Home: http://mailman.qth.net/mailman/listinfo/elecraft
> > Help: http://mailman.qth.net/mmfaq.htm
> > Post: mailto:[hidden email]
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Elecraft mailing list

Re: KPA500 fan won't shut off

In reply to this post by Bill K9YEQ

The KPA runs a check on the memory contents when it starts up. If something has changed that should not, then it will ask for a fresh firmware load. Since Jerry is not seeing this, then I don’t believe there is a firmware issue.

I _am_ concerned about the issue, which is why I suggest calling tech support when they open tomorrow. This has the feel of a stuck relay on the power supply board, but I am sure my friends in Watsonville will have a better idea as to what might be happening.

73!
Jack, W6FB
Elecraft Engineering

> On Jul 14, 2019, at 11:34 AM, Bill Johnson <[hidden email]> wrote:
>
> Try reloading your saved firmware. Could be an internal error which can happen. Reloading firmware, preferably one you have saved will correct the error.
>
> 72 & 73,
> Bill
> K9YEQ
> FT’er for K2, KX1, KX3, KXPA100, KAT500, W2, etc.
>
> -----Original Message-----
> From: [hidden email] <[hidden email]> On Behalf Of jerry
> Sent: Sunday, July 14, 2019 1:23 PM
> To: [hidden email]
> Subject: [Elecraft] KPA500 fan won't shut off
>
> After yesterdays contest, I noticed this morning that the KPA500 fan was still running at a high speed even though the amp had been turned off all night by using the front "on" button. The only way the fan stops running is if I turn the amp on with the front switch or if I shut the amp off by using the rear on/off switch. Menu setting for Fan is set to normal. Any ideas?
>
> ______________________________________________________________
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David Bunte

Re: KPA500 fan won't shut off

In reply to this post by k4vd

Kevin -

As I read Jerry's post, I believe his fan was running even after the amp
had been shut off all night long... and the only way to get it to stop
running at full speed was to either turn the amp on... or turn off the
power switch on the rear. He also stated that the menu setting was set to
NOR, so I think Jack is on the right track to check with support.

Dave - K9FN

On Sun, Jul 14, 2019 at 2:57 PM Kevin, N4TT <[hidden email]> wrote:

> Jerry:
>
> Maybe clarify. I think Jack's concern is that your fan was running even
> with the power off. That's not the case, right? The fan just came back on
> full when you turned the power back on?
>
> Try Menu, scroll down to FAN CTL and make sure that say NOR. If it has a
> number instead, you somehow accidentally set the fan on at that speed. Just
> use the down arrows to get back to NOR. This is all done on the front panel
> of the KPA500. Hope it helps.
>
> 73,
> Kev N4TT
>
> On Sun, Jul 14, 2019 at 2:38 PM Jack Brindle via Elecraft <
> [hidden email]> wrote:
>
> > That means the power is not shutting off. We bleed off the capacitor
> > charge through the fan at front panel shutdown, which is why you hear the
> > fan run for normally a short time.
> > Turn off the KPA using the rear pane switch and call tech support in the
> > morning. They need to look into this one.
> >
> > 73!
> > Jack, W6FB
> >
> >
> > > On Jul 14, 2019, at 11:22 AM, jerry <[hidden email]> wrote:
> > >
> > > After yesterdays contest, I noticed this morning that the KPA500 fan
> was
> > still running at a high speed even though the amp had been turned off all
> > night by using the front "on" button. The only way the fan stops running
> > is if I turn the amp on with the front switch or if I shut the amp off by
> > using the rear on/off switch. Menu setting for Fan is set to normal. Any
> > ideas?
> > >
> > > ______________________________________________________________
> > > Elecraft mailing list
> > > Home: http://mailman.qth.net/mailman/listinfo/elecraft
> > > Help: http://mailman.qth.net/mmfaq.htm
> > > Post: mailto:[hidden email]
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> >
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k4vd

Re: KPA500 fan won't shut off

Cool. I saw "turned off all night" and it surprised me the fan was left
running full speed the whole night.

I'm interested in the outcome.

Kev

On Sun, Jul 14, 2019, 3:13 PM David Bunte <[hidden email]> wrote:

> Kevin -
>
> As I read Jerry's post, I believe his fan was running even after the amp
> had been shut off all night long... and the only way to get it to stop
> running at full speed was to either turn the amp on... or turn off the
> power switch on the rear. He also stated that the menu setting was set to
> NOR, so I think Jack is on the right track to check with support.
>
> Dave - K9FN
>
> On Sun, Jul 14, 2019 at 2:57 PM Kevin, N4TT <[hidden email]> wrote:
>
>> Jerry:
>>
>> Maybe clarify. I think Jack's concern is that your fan was running even
>> with the power off. That's not the case, right? The fan just came back on
>> full when you turned the power back on?
>>
>> Try Menu, scroll down to FAN CTL and make sure that say NOR. If it has a
>> number instead, you somehow accidentally set the fan on at that speed.
>> Just
>> use the down arrows to get back to NOR. This is all done on the front
>> panel
>> of the KPA500. Hope it helps.
>>
>> 73,
>> Kev N4TT
>>
>> On Sun, Jul 14, 2019 at 2:38 PM Jack Brindle via Elecraft <
>> [hidden email]> wrote:
>>
>> > That means the power is not shutting off. We bleed off the capacitor
>> > charge through the fan at front panel shutdown, which is why you hear
>> the
>> > fan run for normally a short time.
>> > Turn off the KPA using the rear pane switch and call tech support in the
>> > morning. They need to look into this one.
>> >
>> > 73!
>> > Jack, W6FB
>> >
>> >
>> > > On Jul 14, 2019, at 11:22 AM, jerry <[hidden email]> wrote:
>> > >
>> > > After yesterdays contest, I noticed this morning that the KPA500 fan
>> was
>> > still running at a high speed even though the amp had been turned off
>> all
>> > night by using the front "on" button. The only way the fan stops
>> running
>> > is if I turn the amp on with the front switch or if I shut the amp off
>> by
>> > using the rear on/off switch. Menu setting for Fan is set to normal. Any
>> > ideas?
>> > >
>> > > ______________________________________________________________
>> > > Elecraft mailing list
>> > > Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> > > Help: http://mailman.qth.net/mmfaq.htm
>> > > Post: mailto:[hidden email]
>> > >
>> > > This list hosted by: http://www.qsl.net
>> > > Please help support this email list: http://www.qsl.net/donate.html
>> > > Message delivered to [hidden email]
>> >
>> > ______________________________________________________________
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>> > Help: http://mailman.qth.net/mmfaq.htm
>> > Post: mailto:[hidden email]
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>> > Message delivered to [hidden email]
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>

ANDY DURBIN

KPA500 fan won't shut off

In reply to this post by jerry-5

"the KPA500 fan was still running at a high speed even though the amp had been turned off all night by using the front "on" button. The only way the fan stops running is if I turn the amp on with the front switch or if I shut the amp off by using the rear on/off switch. Menu setting for Fan is set to normal."

Yes, as Jack suggested, a stuck 60 V enable relay in the PSU fits the symptoms.

That leads to a question though - what does the firmware do if commanded to shutdown but 60 V never bleeds down? I'm guessing it eventually times out or else the fans should have stayed at low speed trying to bleed down the 60 v supply. I also assuming that, when the firmware shuts down, the fan speed control lines default to high speed setting.

When the KPA500 is next powered, but still off, the stuck 60 v enable provides power to the fan and the defaulted control lines make it run at high speed. Once the firmware starts running it detects low PA temperature and sets all fan control lines to off.

Interesting puzzle. Was there a prize?

73,
Andy, k3wyc
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Re: KPA500 fan won't shut off

Dinner on Andy?

Your analysis is spot on. When the KPA is requested to shut down it does some housekeeping, saving various things and putting the amp into a safe condition, including setting the 60V to off. It then sets the fan for full speed operation to bleed off the 60V power and waits for the power button to be released. It finally resets into the boot loader. It does not monitor the 60V voltage at that point. It is an interesting observation that perhaps it should, but the question is then what to do about it. The only thing really is to throw a fault, which puts that amp into a safe mode, but we are already there.

As usual, Andy, you provide great things to think about. I’m not sure there is anything to do about this one, except find out why Jerry’s 60V power is stuck on.

73 and thanks!
Jack, W6FB

> On Jul 14, 2019, at 4:09 PM, Andy Durbin <[hidden email]> wrote:
>
> "the KPA500 fan was still running at a high speed even though the amp had been turned off all night by using the front "on" button. The only way the fan stops running is if I turn the amp on with the front switch or if I shut the amp off by using the rear on/off switch. Menu setting for Fan is set to normal."
>
> Yes, as Jack suggested, a stuck 60 V enable relay in the PSU fits the symptoms.
>
> That leads to a question though - what does the firmware do if commanded to shutdown but 60 V never bleeds down? I'm guessing it eventually times out or else the fans should have stayed at low speed trying to bleed down the 60 v supply. I also assuming that, when the firmware shuts down, the fan speed control lines default to high speed setting.
>
> When the KPA500 is next powered, but still off, the stuck 60 v enable provides power to the fan and the defaulted control lines make it run at high speed. Once the firmware starts running it detects low PA temperature and sets all fan control lines to off.
>
> Interesting puzzle. Was there a prize?
>
> 73,
> Andy, k3wyc
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ANDY DURBIN

Re: KPA500 fan won't shut off

In reply to this post by ANDY DURBIN

"It then sets the fan for full speed operation to bleed off the 60 V power and waits for the power button to be released."

I don't think fan is set to high speed to bleed down the 60 V supply. I think it is set to low speed but may revert to high speed when the firmware shuts down with 60 V is still present.

Try this simple test - With KPA500 powered and On, use menu to set minimum fan speed 6. Then shut down with the front panel On button. Fan immediately reduces to speed 1 and holds speed 1 until it slows down as the 60 V supply bleeds down.

The firmware could detect that 60 V has not decayed below min monitor threshold and issue a fault. That fault code could perhaps alert the operator to turn off the rear panel power switch and seek assistance. Better to be alerted at shutdown time than find the fans still running the next day.

There is a potential safety issue with a stuck 60 V enable relay. The interlock switch is in the relay coil coil circuit and offers no protection if the relay is stuck on.

On the other hand - how often does the 60 V enable relay fail ....

73,
Andy, k3wyc

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VK5GR

Re: KPA500 fan won't shut off

Folks,

Has there been any further word on this fault? I have just had the same
thing happen to me and am wondering if it could be the same issue?

Regards,
Grant VK5GR

--
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Bob McGraw - K4TAX

Re: KPA500 fan won't shut off

What is the value in the menu for FAN CTL?   If at NOR then the fan
should be off until the temp hits about 50º C. It will then increment
up one speed value about every 5 degrees temp increase.   What is the
TEMP value showing?   Should be about room temp or 22 to 25 C

73

Bob, K4TAX

On 11/25/2019 7:57 PM, VK5GR wrote:

> Folks,
>
> Has there been any further word on this fault? I have just had the same
> thing happen to me and am wondering if it could be the same issue?
>
> Regards,
> Grant VK5GR
>
>
>
>
> --
> Sent from: http://elecraft.365791.n2.nabble.com/
> ______________________________________________________________
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VK5GR

Re: KPA500 fan won't shut off

FAN CTL = NOR

FANs are idle while the amp is turned on - amp ambient temp was 27C at the
time (it was powered up and had been idle for about 20 minutes).

I then turned the amplifier off via the front panel push button. I would
have expected the FANs to start up for about 10 seconds as they discharge
the 60V rail supply but instead the FANs continue to run. the only way to
turn them off is to unplug the amp from the mains supply.

It is definitely a fault condition and not a menu selection.

Thoughts?

--
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Bob McGraw - K4TAX

Re: KPA500 fan won't shut off

Does the mains switch on the rear panel shut the fan off?
I would next reload the firmware.

Bob, K4TAX

Sent from my iPhone

> On Nov 25, 2019, at 8:50 PM, VK5GR <[hidden email]> wrote:
>
> FAN CTL = NOR
>
> FANs are idle while the amp is turned on - amp ambient temp was 27C at the
> time (it was powered up and had been idle for about 20 minutes).
>
> I then turned the amplifier off via the front panel push button. I would
> have expected the FANs to start up for about 10 seconds as they discharge
> the 60V rail supply but instead the FANs continue to run. the only way to
> turn them off is to unplug the amp from the mains supply.
>
> It is definitely a fault condition and not a menu selection.
>
> Thoughts?
>
>
>
> --
> Sent from: http://elecraft.365791.n2.nabble.com/
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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Eric Norris-2

Re: KPA500 fan won't shut off

In reply to this post by VK5GR

Reload the firmware.

73 Eric WD6DBM

On Mon, Nov 25, 2019, 6:51 PM VK5GR <[hidden email]> wrote:

> FAN CTL = NOR
>
> FANs are idle while the amp is turned on - amp ambient temp was 27C at the
> time (it was powered up and had been idle for about 20 minutes).
>
> I then turned the amplifier off via the front panel push button. I would
> have expected the FANs to start up for about 10 seconds as they discharge
> the 60V rail supply but instead the FANs continue to run. the only way to
> turn them off is to unplug the amp from the mains supply.
>
> It is definitely a fault condition and not a menu selection.
>
> Thoughts?
>
>
>
> --
> Sent from: http://elecraft.365791.n2.nabble.com/
> ______________________________________________________________
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Re: KPA500 fan won't shut off

That won’t do any good. The main firmware has shut down at that point. The fan is running because the relay is stuck, which is not something that firmware can fix.

Call tech support.

73!
Jack, W6FB

> On Nov 25, 2019, at 7:49 PM, Eric Norris <[hidden email]> wrote:
>
> Reload the firmware.
>
> 73 Eric WD6DBM
>
> On Mon, Nov 25, 2019, 6:51 PM VK5GR <[hidden email]> wrote:
>
>> FAN CTL = NOR
>>
>> FANs are idle while the amp is turned on - amp ambient temp was 27C at the
>> time (it was powered up and had been idle for about 20 minutes).
>>
>> I then turned the amplifier off via the front panel push button. I would
>> have expected the FANs to start up for about 10 seconds as they discharge
>> the 60V rail supply but instead the FANs continue to run. the only way to
>> turn them off is to unplug the amp from the mains supply.
>>
>> It is definitely a fault condition and not a menu selection.
>>
>> Thoughts?
>>
>>
>>
>> --
>> Sent from: http://elecraft.365791.n2.nabble.com/
>> ______________________________________________________________
>> Elecraft mailing list
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VK5GR

Re: KPA500 fan won't shut off

In reply to this post by Eric Norris-2

Eric,

I reloaded the firmware tonight – no change (in fact I upgraded it from 1.47 to 1.54).

If I plug the mains cable in the fans power up immediately. If I then turn the amplifier on, the amp works normally. When I power it off from software or the front panel the fans spin up and stay running.

Is there something I can look at here in VK I wonder? I really don’t want to have to ship it back to Elecraft for this.

Regards,

Grant VK5GR

From: Eric Norris [mailto:[hidden email]]
Sent: Tuesday, 26 November 2019 2:20 PM
To: VK5GR
Cc: elecraft@mailman qth. net
Subject: Re: [Elecraft] KPA500 fan won't shut off

Reload the firmware.

73 Eric WD6DBM

On Mon, Nov 25, 2019, 6:51 PM VK5GR <[hidden email]> wrote:

FAN CTL = NOR

FANs are idle while the amp is turned on - amp ambient temp was 27C at the
time (it was powered up and had been idle for about 20 minutes).

I then turned the amplifier off via the front panel push button. I would
have expected the FANs to start up for about 10 seconds as they discharge
the 60V rail supply but instead the FANs continue to run. the only way to
turn them off is to unplug the amp from the mains supply.

It is definitely a fault condition and not a menu selection.

Thoughts?

--
Sent from: http://elecraft.365791.n2.nabble.com/
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Eric Norris-2

Re: KPA500 fan won't shut off

As Jack Brindle noted (and he would know), it appears to be a stuck relay.
If you don't want to send the amp back to the mothership, I'm sure Elecraft
Support could identify the relay, and if you can do rework, you could
remove the bad one and replace it yourself.

73 Eric WD6DBM

On Tue, Nov 26, 2019, 12:57 AM Grant VK5GR <[hidden email]> wrote:

> Eric,
>
>
>
> I reloaded the firmware tonight – no change (in fact I upgraded it from
> 1.47 to 1.54).
>
>
>
> If I plug the mains cable in the fans power up immediately. If I then turn
> the amplifier on, the amp works normally. When I power it off from software
> or the front panel the fans spin up and stay running.
>
>
>
> Is there something I can look at here in VK I wonder? I really don’t want
> to have to ship it back to Elecraft for this.
>
>
>
> Regards,
>
> Grant VK5GR
>
>
>
>
>
>
>
>
>
> *From:* Eric Norris [mailto:[hidden email]]
> *Sent:* Tuesday, 26 November 2019 2:20 PM
> *To:* VK5GR
> *Cc:* elecraft@mailman qth. net
> *Subject:* Re: [Elecraft] KPA500 fan won't shut off
>
>
>
> Reload the firmware.
>
> 73 Eric WD6DBM
>
>
>
> On Mon, Nov 25, 2019, 6:51 PM VK5GR <[hidden email]> wrote:
>
> FAN CTL = NOR
>
> FANs are idle while the amp is turned on - amp ambient temp was 27C at the
> time (it was powered up and had been idle for about 20 minutes).
>
> I then turned the amplifier off via the front panel push button. I would
> have expected the FANs to start up for about 10 seconds as they discharge
> the 60V rail supply but instead the FANs continue to run. the only way to
> turn them off is to unplug the amp from the mains supply.
>
> It is definitely a fault condition and not a menu selection.
>
> Thoughts?
>
>
>
> --
> Sent from: http://elecraft.365791.n2.nabble.com/
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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> Post: mailto:[hidden email]
>
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> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]
>
>

ANDY DURBIN

KPA500 fan won't shut off

In reply to this post by jerry-5

"As Jack Brindle noted (and he would know), it appears to be a stuck relay."

Ok, I'll bite. How would a mechanically stuck relay be freed by cycling power?

Andy, k3wyc
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ANDY DURBIN

Re: KPA500 fan won't shut off

"Ok, I'll bite. How would a mechanically stuck relay be freed by cycling power? "

Never mind. I should have checked my notes first. Stuck K1 in the PSU would seem to fit the symptoms.

Andy, k3wyc

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