[K1] No power out

[Bob Molloy]

Hi,

 

I'm in Chapter 9, Alignment and Test, Part II. I've done the first set of
voltage checks and the values are all good.

 

Now I have moved on to Band 1 Alignment (40 meters). No position of L1, L2,
L5 or L6 has any effect. The display continues to show P0.1. (Also tried
Band 2 (20 meters) with the same result.)

 

What steps should I take next?

 

Thanks,

Bob KD2UJ

 

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[Don Wilhelm-4]

Bob,

I believe you will need an RF Probe or a 'scope with a 10X probe to proceed.

First step is to check to see if you have RF from the crystal - P1 pin 4
of the band board.
Check on both bands.
Assuming you do have RF from the crystal, the next step is to check for
RF at P1 pin 6 - tune the Premixer inductors for maximum amplitude while
probing that point.

Once you have the PreMixer output, you can peak the RF Bandpass filter
in receive - if you have a signal generator that is great, if not and
you have another transmitter, feed that transmitter into a dummy load
and put a pickup wire on the antenna connector of the K1.

After you have the K1 receiving, then try transmit again and touch up
the premixer and rf bandpass filters during transmit.

73,
Don W3FPR

On 8/9/2012 12:26 PM, Bob Molloy wrote:

> Hi,
>
> I'm in Chapter 9, Alignment and Test, Part II. I've done the first set of
> voltage checks and the values are all good.
>
> Now I have moved on to Band 1 Alignment (40 meters). No position of L1, L2,
> L5 or L6 has any effect. The display continues to show P0.1. (Also tried
> Band 2 (20 meters) with the same result.)
>
> What steps should I take next?
>
>  
>
>

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[Bob Molloy]

Don,

First of all I couldn't have solved this without your help. Thanks very
much. Elecraft should be paying you for your services.

The symptom was "no power out" during the band alignment of a 2-band filter
board in "9. Alignment and Test, Part II." Here is a recap of what it took
to fix this problem:

It quickly became obvious that I needed an RF probe. I ordered kit RFPROBE
from Elecraft. It arrived here in about 2 days.

Almost everything else I did was at the direction of Don W3FPR. The first
symptom he attacked was: no voltage on FIL-P1 Pin 6.

1. Peaked the RF voltage on the left side of C3 using L1.

2. Peaked the right side of C3 using L2.

3. Did the same for C8 using L3 and L4.

4. Peaked the voltage at FIL-P1 Pin 6 on both bands.

5. Now I reran all the steps in "7. Alignment and Test, Part I" to get the
receiver aligned. Still no transmit power.

6. Started Transmitter Signal Tracing as described in "Appendix E,
Troubleshooting."

7. Everything looked good up to the BPF (bandpass filter) test point where
the voltage was zero.

8. Checked Band 2 (20 meters) and it was fine.

9. Pulled the filter board to inspect the solder joints in the Band 1
bandpass filter area. Found a couple that looked iffy.

10. Re-soldered the joints that looked incomplete and reflowed most of the
others.

11. Re-installed the filter board and now had 2 Watts out on both bands.

I wish the RF probe was included in the K1 kit, but at least it was
available for ordering at a reasonable price.

Learned a lot. Looking forward to finishing and getting the K1 on the air.

73,
Bob  KD2UJ


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[Don Wilhelm-4]

Bob,

Actually Elecraft does pay me for the repair work I do.  The email
effort I spend here on the reflector is volunteer.  I have been doing it
that way for a long time now - since the original K2 Field Test in 1999

73,
Don W3FPR

On 8/16/2012 12:08 PM, Bob Molloy wrote:
> Don,
>
> First of all I couldn't have solved this without your help. Thanks very
> much. Elecraft should be paying you for your services.
>
>

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[Bob Molloy]

Just an FYI since it's a little hard to find, the RFPROBE kit is on this
page http://www.elecraft.com/order_form_parts.htm#K2%20Parts under K2 PARTS
AND MOD KITS.

 

Bob KD2UJ

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