First Alignment and Test problem #5703

[NZ0T]

I got to the first test stage tonight and while the rig came on with no
smoke there is nothing on the LCD display. I hear the relays clicking and
the backlight is on but no characters at all.  The front panel is plugged in
fine and I reset it just to make sure.  Dittos for the control board.  All
the intermediate resistance checks were.  Any input as to where to start
looking would be appreciated!

Thanks and 73,

Bill NZ0T


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[John E. Reiser]

Hi Bill,

When you did your resistance checks for the front panel board, were any of
them outside of the expected range on the low side?

John, W2GW

----- Original Message -----
From: "Bill Carpenter" <[hidden email]>
To: "elecraft list" <[hidden email]>
Sent: Thursday, August 24, 2006 11:52 PM
Subject: [Elecraft] First Alignment and Test problem #5703

>I got to the first test stage tonight and while the rig came on with no
>smoke there is nothing on the LCD display. I hear the relays clicking and
>the backlight is on but no characters at all.  The front panel is plugged
>in fine and I reset it just to make sure.  Dittos for the control board.
>All the intermediate resistance checks were.  Any input as to where to
>start looking would be appreciated!
>
> Thanks and 73,
>
> Bill NZ0T
>
> _______________________________________________
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[Don Wilhelm-3]

Bill,

One often repeated error in assembly is failure to solder pin 1 of the Front
Panel U1 socket - result is a blank display.

Peer carefully under the LCD and backlight assembly and see if pin 1 is
soldered.
If it is not soldered, therre is a way to solder it without removing the LCD
(which is a nasty task) - cut away a small portion of the plastic outside
pin 1 (cut at the bottom of the socket), so you can place the tip of the
soldering iron on the pin from the socket side while feeding a bit of solder
on the other side of the board.

You may want to vow to always solder IC pin 1 first on all ICs during your
assembly.  The pad for pin 1 is round as a unique marker while the others
are square.  Sometimes the eyes miss that single round pin.

73,
Don W3FPR

> -----Original Message-----
>
> I got to the first test stage tonight and while the rig came on with no
> smoke there is nothing on the LCD display. I hear the relays clicking and
> the backlight is on but no characters at all.  The front panel is
> plugged in
> fine and I reset it just to make sure.  Dittos for the control
> board.  All
> the intermediate resistance checks were.  Any input as to where to start
> looking would be appreciated!
>
> Thanks and 73,
>
> Bill NZ0T
>

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[g3ymc]

On 26 Aug 2006 at 4:02, W3FPR wrote:

>
> One often repeated error in assembly is failure to solder pin 1 of the Front
> Panel U1 socket - result is a blank display.
>
> Peer carefully under the LCD and backlight assembly and see if pin 1 is
> soldered.
> If it is not soldered, therre is a way to solder it without removing the LCD
> (which is a nasty task) - cut away a small portion of the plastic outside
> pin 1 (cut at the bottom of the socket), so you can place the tip of the
> soldering iron on the pin from the socket side while feeding a bit of solder
> on the other side of the board.
>
> You may want to vow to always solder IC pin 1 first on all ICs during your
> assembly.  The pad for pin 1 is round as a unique marker while the others
> are square.  Sometimes the eyes miss that single round pin.
>
> 73,
> Don W3FPR
>

Well I reached the same point in the assembly of #4848. I had just
read your posting and said 'well at least I won't make that mistake' -
 I am a seasoned builder and this is my second K2.

Guess what, switched on for the first stage testing and lcd lit up,
relays clicked but no display. Did a bit of tracing, got my dmm out,
and you guessed it, pin 1 of U1 was not connected!!

To avoid dismantling the front panel assembly and not wishing to
mangle the ic socket I added a wire link soldered directly to U1
itself and to the lower end of R7.

K2 now working fine at stage 1.

73 Dave G3YMC



http://www.davesergeant.com

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