Re: [Elecraft] KPA500 / 270V ERR

[Andy Durbin]

"He tells me that a failed R16 on the power supply board should have no effect 
on the 60V supply, ."

No, of course it won't.  It will only prevent 270 V being produced if 60 V is 
present.   The amplifier is heavy and will be expensive to ship.  Why not 
diagnose the problem and just fix what has failed?

You have already determined that mains voltage is reaching the low voltage 
supply since you have the display and control panel working.  There really 
isn't much that can kill 60 V if there is input to the main transformer T1.

Failure can probably be isolated to T1, the diode bridge,  the 60 V enable 
relay, and their interconnections (assuming the power supply rails really have 
failed and this isn't a sensing problem).   The problem could be as simple as a 
poor contact on the transformer tap.  The hardest part of the job is removing 
all the screws to gain access to make measurements.

Perhaps the best thing about building a kit is not the small cost saving but 
gaining the confidence to open it up if needed.

Andy, k3wyc
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Re: [Elecraft] KPA500 / 270V ERR

[James Bennett via Elecraft]

Folks - I’ve exchanged email with Rob at Elecraft support. He tells me that a 
failed R16 on the power supply board should have no effect on the 60V supply, 
so I’m opting to NOT rip the amp apart in search of R16. Waiting on Rob to send 
me an RSA and the amp will be off to Watsonville for some first aid. I’ll post 
back here when it is returned and let you know what went south.

73, Jim / K7TXA


> 
>> On Jul 17, 2022, at 4:04 PM, Bruce Forsberg > > wrote:
>> 
>> James I had the 270 V Err message on my KPA500 as well, S/N 3406. It turned
>> out to be R16 on the PS board had opened (S/B 100 ohms). This resistor
>> feeds the voltage multiplier circuit to get to 270V. Don't know if this is
>> your problem or not but does not hurt to check. It is an SMD resistor and I
>> think is accessible from the top.
>> 
>> Bruce, WB6IZG
>> 
>> On Sun, Jul 17, 2022 at 2:51 PM James Bennett via Elecraft <
>> elecraft@mailman.qth.net > wrote:
>> 
>>> Hi - I’ve had my KPA500 serial number 3645 for several years and until
>>> today have had zero problems with it. Previously it was driven by a K3;
>>> currently (until today!) a K4D. Last time I used it, it worked great. Today
>>> I powered it on after having it off for several days and when I went to
>>> Operate mode, I got the dreaded 270V ERR display. When I display HV it
>>> shows “1”. Everything else seems to be OK - band changing works fine,
>>> metering of the power and frequency are OK - just can’t go to Operate mode.
>>> The top cover is on just as tight as it has been for years. Fuses are all
>>> OK.
>>> 
>>> Looked through the archives and did see a few hits, but most were related
>>> to loose top cover or incorrect voltage settings.
>>> 
>>> I’ve fired off an email to Elecraft support earlier today but thought I’d
>>> run it by the owner community too.
>>> 
>>> Suggestions?
>>> 
>>> Jim Bennett / K7TXA
>>> Eagle, ID
>>> 
>>> 
>>> 
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>>> 
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Re: [Elecraft] KPA500 / 270V ERR

[Andy Durbin]

"If you check the schematics, the 270V is made/comes from the power 
supply...BUT the 60V enable relay (feeds the voltage divider and read on the 
front panel) is on the PA board... "

May I suggest that you look at KPA Power Supply Schematic sheet 1 of 2 and 
locate relay K1 (60 V Enable) which is controlled by the interlock switch and 
signal 60 V ENBL.

How is 270 V produced if this relay is open?

How is 270 v produced if 60 V is not present?

I do not think it a coincidence that the OP has lost 270 V and 60 V.  I suspect 
a common cause.

Andy, k3wyc


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Re: [Elecraft] KPA500 / 270V ERR

[Andy Durbin]

"I think it may actually be the other way around... The 60V relay does not 
close if 270V is missing?"

Assume 60 V Enable relay K1 is not closed.  How would 270 V be produced?  The 
secondary winding of T1 is open circuit.

Andy, k3wyc
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Re: [Elecraft] KPA500 / 270V ERR

[Dr. William J. Schmidt]

I think it may actually be the other way around... The 60V relay does not
close if 270V is missing?

-Original Message-
From: elecraft-boun...@mailman.qth.net  On
Behalf Of Andy Durbin
Sent: Sunday, July 17, 2022 6:49 PM
To: elecraft@mailman.qth.net
Subject: [Elecraft] KPA500 / 270V ERR

HV and 270V are separate power supply rails but, if my read of the schematic
is correct, 270 V depends on 60 V being present.  60 V requires the
interlock switch to be closed.

Diagnosing this may require having the top off and the interlock defeated.
Everyone should evaluate their own competence and risk tolerance.

Andy, k3wyc

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[Elecraft] KPA500 / 270V ERR

[Andy Durbin]

HV and 270V are separate power supply rails but, if my read of the schematic is 
correct, 270 V depends on 60 V being present.  60 V requires the interlock 
switch to be closed.

Diagnosing this may require having the top off and the interlock defeated.  
Everyone should evaluate their own competence and risk tolerance.

Andy, k3wyc

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Re: [Elecraft] KPA500 / 270V ERR

[Bruce Forsberg]

James I had the 270 V Err message on my KPA500 as well, S/N 3406. It turned
out to be R16 on the PS board had opened (S/B 100 ohms). This resistor
feeds the voltage multiplier circuit to get to 270V. Don't know if this is
your problem or not but does not hurt to check. It is an SMD resistor and I
think is accessible from the top.

Bruce, WB6IZG

On Sun, Jul 17, 2022 at 2:51 PM James Bennett via Elecraft <
elecraft@mailman.qth.net> wrote:

> Hi - I’ve had my KPA500 serial number 3645 for several years and until
> today have had zero problems with it. Previously it was driven by a K3;
> currently (until today!) a K4D. Last time I used it, it worked great. Today
> I powered it on after having it off for several days and when I went to
> Operate mode, I got the dreaded 270V ERR display. When I display HV it
> shows “1”. Everything else seems to be OK - band changing works fine,
> metering of the power and frequency are OK - just can’t go to Operate mode.
> The top cover is on just as tight as it has been for years. Fuses are all
> OK.
>
> Looked through the archives and did see a few hits, but most were related
> to loose top cover or incorrect voltage settings.
>
> I’ve fired off an email to Elecraft support earlier today but thought I’d
> run it by the owner community too.
>
> Suggestions?
>
> Jim Bennett / K7TXA
> Eagle, ID
>
>
>
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[Elecraft] KPA500 / 270V ERR

[James Bennett via Elecraft]

Hi - I’ve had my KPA500 serial number 3645 for several years and until today 
have had zero problems with it. Previously it was driven by a K3; currently 
(until today!) a K4D. Last time I used it, it worked great. Today I powered it 
on after having it off for several days and when I went to Operate mode, I got 
the dreaded 270V ERR display. When I display HV it shows “1”. Everything else 
seems to be OK - band changing works fine, metering of the power and frequency 
are OK - just can’t go to Operate mode. The top cover is on just as tight as it 
has been for years. Fuses are all OK.

Looked through the archives and did see a few hits, but most were related to 
loose top cover or incorrect voltage settings.

I’ve fired off an email to Elecraft support earlier today but thought I’d run 
it by the owner community too.

Suggestions?

Jim Bennett / K7TXA
Eagle, ID



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[Elecraft] [KPA500] 270V ERR

[Andy Durbin]

"We are constantly getting the "270V ERR" when switching over to OPER.  We have 
checked that the micro-switch is working properly and is correctly operated by 
the lid."

If it were mine I'd measure the voltage and ask for the low and high warning 
levels.   Of course you must take proper precautions.  There is a reason there 
is an interlock switch. 

My KPA 500 notes include this:

"Investigation revealed
the PSU board multiplier could produce 210V OFF LOAD with the PSU>LPF jumper
disconnected but only 60v when the jumper was connected. Simulating the pin
diode current consumption with a resistor also produced the same result.
Turned out that R16 which should have been 100 ohm was now 1.2Mohm.
Replacing it fixed that problem

While talking to elecraft support it transpired that there was an upgrade
kit (E850607) that replaces the Q5 FET on the LPF board with a transistor
(as usual no reference could be found to it on the elecraft web site!). This
upgrade has also now been done"

I regret that I did not record the source.

Andy, k3wyc
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Re: [Elecraft] [KPA500] 270V ERR

[Jack Brindle via Elecraft]

It sounds like you really need to contact the tech support guys for this one. 
The small cable from the microswitch plugs into the Power Supply board. Make 
sure it is properly seated. It is behind the big toroid transformer, so you may 
have to move that to check. The signal indicating that 270V is bad comes from 
the PA module to the front panel over the ribbon cable that is permanently 
attached to the PA sandwich. Make sure that cable is securely plugged into the 
front panel connector.

The 270V is enabled when the KPA500 goes into OPER mode. If you always get this 
fault when switching from STBY to OPER, it is an indication that something is 
not right in the power supply. Again, contact Customer Support to get their 
help in tracing this down.

To specifically answer your question, it is ’NO'. The IO board has no part in 
getting the 270V supply going, checked, and reported to the front panel board.

Good luck getting the KPA500 going again. It is a great amplifier! But then I’m 
a bit biased…

73!
Jack Brindle, W6FB
Elecraft Engineering

> On Aug 7, 2020, at 9:11 AM, LA7NO  wrote:
> 
> Hello,
> 
> We are constantly getting the "270V ERR" when switching over to OPER.
> We have checked that the micro-switch is working properly and is correctly
> operated by the lid.
> We have also tried the power reset, but still the same.
> 
> We know there is a problem with the I/O card, since we are not able to get a
> PC connected to the serial port - RS232 (PC).
> So, we can not use the KPA500 Utility Program.
> 
> Is it in any way possible that a fault on the I/O-card can cause the "270V
> ERR" message?
> 
> 73,
> 
> Per-Tore
> LA7NO
> 
> 
> 
> 
> -
> 73,
> 
> Per-Tore / LA7NO
> 
> --
> Sent from: http://elecraft.365791.n2.nabble.com/
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Re: [Elecraft] [KPA500] 270V ERR

[Augie "Gus" Hansen]

Be certain that both ends of the heavy power cable between the PS and 
the amp are properly installed. Unplug the power pole connectors and 
reinsert them fully until you hear and feel the click.


This ERR indication happened to my KPA1500 recently because the APP on 
the amp end was slightly loose. I have revised my cabling layout to put 
some strain relief on that heavy cable to prevent this problem from 
recurring.


Gus Hansen
KB0YH (proud son of Norway!)


On 8/7/2020 10:11 AM, LA7NO wrote:

Hello,

We are constantly getting the "270V ERR" when switching over to OPER.
We have checked that the micro-switch is working properly and is correctly
operated by the lid.
We have also tried the power reset, but still the same.

We know there is a problem with the I/O card, since we are not able to get a
PC connected to the serial port - RS232 (PC).
So, we can not use the KPA500 Utility Program.

Is it in any way possible that a fault on the I/O-card can cause the "270V
ERR" message?



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[Elecraft] [KPA500] 270V ERR

[LA7NO]

Hello,

We are constantly getting the "270V ERR" when switching over to OPER.
We have checked that the micro-switch is working properly and is correctly
operated by the lid.
We have also tried the power reset, but still the same.

We know there is a problem with the I/O card, since we are not able to get a
PC connected to the serial port - RS232 (PC).
So, we can not use the KPA500 Utility Program.

Is it in any way possible that a fault on the I/O-card can cause the "270V
ERR" message?

73,

Per-Tore
LA7NO




-
73,

Per-Tore / LA7NO

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[Elecraft] KPA500 270V ERR

[Paul DeFelice]

I sent the following email to Elecraft support today but would appreciate
any input that the reflector could offer.

 

73 Paul K9NU

 

My KPA500 (S/N 1073) gave me a 270V ERR message last evening. I removed
the top cover (over-road the interlock switch) unplugged the white connector
from the PA assembly and measured the no-load voltage at the  gray wire.
When AC power is applied, the voltage slowly rises to at best, 180 Vdc
(starts off at about 90 volts and slowly raises to 180 volts in 15 seconds).
The 75 volt supply is work fine. I have removed the power supply board from
the amp. I see no visual damage to the board taking particular notice in the
270 volt area of the PCB. I applied 55 Vac to J1  J2 via an Isolation
transformer and a variac. One at a time, I paralleled c9 thru c14 with
another 10UF, 100 volt capacitor with no change in the output voltage noted.
The voltage drop across each diode of the 6 diodes (d7, 8,  9) is around 8
to 10 volts.

Can you give me some input as to where or what to do next? Some test point
voltages would me great.

 

73,

Paul K9NU

 

 

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[Elecraft] (KPA500) 270V ERR

[Bill Conkling]

Just finished my KPA500 last night.  Plugged it in and it lit up.  Hooray!  
Went to bed happy.  Today I pressed the button to get out of standby and
lo and behold, I got a FAULT and the error displayed 270V ERR.  Took side
panel off and checked cables, tap and anything I could see, all ok.  Saftey
switch appears just as in book, and the actuator assembly looks right.

Help!  Please...

...bill nr4c

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