[Elecraft] KPA 500 fault!

[Dave Cole]

Ian,
Could you also send me a copy, I have an older amp as well.

73, and thanks,
Dave (NK7Z)
https://www.nk7z.net
ARRL Volunteer Examiner
ARRL Technical Specialist
ARRL Asst. Director, NW Division, Technical Resources

On 5/3/20 1:14 PM, iain macdonnell - N6ML wrote:
> On my early model, the interlock switch is actuated by an assembly
> including a 13mm 4-40 standoff (and some other hardware), which is
> attached to the inside of the top cover. I'll attempt to send you the
> old (rev C) assembly manual off-list.
> 
> 73,
> 
>      ~iain / N6ML
> 
> 
> On Sun, May 3, 2020 at 1:07 PM Tom Doligalski via Elecraft
> <elecraft at mailman.qth.net> wrote:
>>
>> Problem is definitely the interlock switch not being engaged correctly: if I close it manually (with a wooden rod!) the amp operates normally.
>>
>> Anyone have an assembly manual for the older type KPA500, so I can see how the top-panel interlock switch is supposed to be engaged? Again, this a fairly old amp, and Elecraft changed things in later versions (like the one covered in the assembly manual currently on the website).
>>
>> Thanks!
>>
>> Tom W4KX
>>
>>> On May 3, 2020, at 3:21 PM, Tom Doligalski via Elecraft <elecraft at mailman.qth.net> wrote:
>>>
>>> Hi Jack!
>>>
>>> After cycling the main power the HV in standby is back to 70 V. But, every time I go to operate mode, the error reoccurs.
>>>
>>> This is with what I believe was the old style interlock switch (has a shaft attached to the top cover to engage the switch when the top is screwed down). Can’t tell if it is properly engaging. But the behavior is the same when the top cover is totally removed.
>>>
>>> How picky is this switch. I bought the amp used, and the assembly manual online at elecraft doesn’t cover the old interlock switch.
>>>
>>> Thanks for your help!
>>>
>>> Tom W4KX
>>>
>>> Sent from my iPad
>>>
>>>> On May 3, 2020, at 3:06 PM, Jack Brindle <jackbrindle at me.com> wrote:
>>>>
>>>> A “270V ERR” fault indicates that the TR switch bias supply is not working. This may be caused by the top cover being removed, the safety switch attached to the top cover becoming loose or an actual failure of the 270V supply. Since your main HV supply is now down close to 0V, it looks like you have power supply issues. You should call technical support on Monday to get help.
>>>>
>>>> 73 and good luck getting your KPA going again.
>>>> Jack, W6FB
>>>>
>>>>
>>>>> On May 3, 2020, at 11:32 AM, Tom Doligalski via Elecraft <elecraft at mailman.qth.net> wrote:
>>>>>
>>>>> My KPA500 has been working fine waited for 115 V. Just now it has been throwing a “25=70 VAC” fault!
>>>>>
>>>>> Can anyone lead me in helping this? Fuses look good. HV read 0.1 v when in standby, which is FAR from the 70 some volts it used to read.
>>>>>
>>>>> Thanks!
>>>>>
>>>>> Tom W4KX
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