In looking at the schematic, I see the fan is controlled by a MJE182
{Q5}. If this transistor shorts the fan runs at full speed. I didn't
see a relay in the circuit, but I could have missed it.
73
Bob, K4TAX
On 11/26/2019 3:29 AM, Eric Norris wrote:
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 <vk5gr.ra...@gmail.com> 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:norrislawfi...@gmail.com]
*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 <vk5gr.ra...@gmail.com> 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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