KIO2 help!

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KIO2 help!

Michael Lawton
  Having just completed the KIO2 module, I discovered that the onboard oscillator doesn't. I've isolated it, had it apart twice, checked all components and pcb lands, replaced the FET even though my analyser said it was OK. The FET is running very hot, perhaps 50 deg C. If I inject the required negative voltage into pin 8 of the IC, all voltages come up correct on the pins, so it doesn't seem to be anything to do with that. I'm just about to knock up a crystal checker, but while I do, has anyone else had this problem?

  73 de Mike GW4IQP
  G-QRP, K2 no 4185
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RE: KIO2 help!

Don Wilhelm-3
Mike,

You mentioned that Q1 was getting hot - it does not normally.  The only
thing that I can spot on the schematic for possibilities is D4 - if it were
reversed, it would place 5 volts on the gate of Q1 and make it conduct
heavily.  The anode (unmarked end) of D4 should be closest to the edge of
the board.

73,
Don W3FPR

> -----Original Message-----
>
>   Having just completed the KIO2 module, I discovered that the
> onboard oscillator doesn't. I've isolated it, had it apart twice,
> checked all components and pcb lands, replaced the FET even
> though my analyser said it was OK. The FET is running very hot,
> perhaps 50 deg C. If I inject the required negative voltage into
> pin 8 of the IC, all voltages come up correct on the pins, so it
> doesn't seem to be anything to do with that. I'm just about to
> knock up a crystal checker, but while I do, has anyone else had
> this problem?
>
>   73 de Mike GW4IQP
>   G-QRP, K2 no 4185
>

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