K1 - High current drain on power on

[VP8ROT]

Hello everyone, I'm sorry to trouble you with something which you've probably had posted a thousand times. I'm very new to the hobby and am struggling to get the K1 to work.

Symptom: Up power on the current drain is high (as much as I would allow the bench supply to give).
This is with just the RF board and front panel connected. Supply is a bench supply with 12.5v and max 1 amp.

On my first attempt to use the rig the Q7 on the finals melted. This has been replaced but it was clearly the poor recipient of the high current and not the cause.

I have carefully checked each component is in the correct place and orientation.
I've checked each solder joint.

What I need are some places to start troubleshooting the issue. Your assistance will be greatly appreciated.

73
Ian
VP8DLJ

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[Don Wilhelm-4]

Ian,

Check and re-check T4 to be certain the windings are not interchanged.
Secondly, check to see if the High Current condition occurs on all
bands.  If it is only on one band, the suspect the Low Pass Filter for
that band.

Check the base DC voltage of Q7 during transmit.  If it is other than
zero volts, you should look for a solder splash somewhere that is
causing Q7 to conduct heavily.

These are only starters - there is no one answer to a problem such as
this - there can be several causes, only to be revealed with further
measurements.

73,
Don W3FPR

Ian Nightingale wrote:

> Hello everyone, I'm sorry to trouble you with something which you've probably had posted a thousand times. I'm very new to the hobby and am struggling to get the K1 to work.
>
> Symptom: Up power on the current drain is high (as much as I would allow the bench supply to give).
> This is with just the RF board and front panel connected. Supply is a bench supply with 12.5v and max 1 amp.
>
> On my first attempt to use the rig the Q7 on the finals melted. This has been replaced but it was clearly the poor recipient of the high current and not the cause.
>
> I have carefully checked each component is in the correct place and orientation.
> I've checked each solder joint.
>
> What I need are some places to start troubleshooting the issue. Your assistance will be greatly appreciated.
>
> 73
> Ian
> VP8DLJ
>
> _______________________________________________
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