XRef - 10MHz-Locked Reference Oscillator

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Re: XRef - 10MHz-Locked Reference Oscillator

Postby VK3HZ » Mon Apr 25, 2016 8:52 am

Hi Kevin,

There was an issue with some of the earlier boards where, under certain conditions, the divider chip could "take off" when the synthesizer was disabled (i.e. running the rig without 10 MHz connected). This then interfered with the standard Kenwood reference oscillator causing some strange effects.

There's a simple fix which was applied to later boards, then incorporated in a recent redesign of the PCB. I'll describe the mod in the next posting.

If you don't want to try the mod yourself, return the board to me and I'm happy to do it.

Regards,
Dave
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Re: XRef - 10MHz-Locked Reference Oscillator

Postby VK3HZ » Mon Apr 25, 2016 9:32 am

XRef-VS Modification

Under certain conditions, some XRef-VS boards can generate a spurious output when the XRef is supposedly disabled (i.e. no 10 MHz applied).
The XRef-VS is mainly used for the TS-2000 and the IC-910H fitted with a hi-stab OEM oscillator.

The mod is applicable to XRef-VS boards delivered prior to the start of 2015. Later boards already have this modIfication. From the start of 2016, this mod is incorporated in the redesigned PCB.

** Note - This mod is NOT required and MUST NOT be done to an XRef-VT, XRef-FT or XRef-PLL board. **

You need a 10K 1/8W standard (i.e. not SMD) resistor - the smaller the better. You also need a short length of wire.

The mods are shown in red on the PCB overlays below. Note that these overlays show the full set of components used for both versions (VS and VT). The VS does not have anything where the large square outlines are shown (TCXO and adjustment trimpot, only on the VT).

Xref VS top mod.jpg
Top of PCB
Xref VS bottom mod.jpg
Underside of PCB

Begin by removing the SMD resistor that is crossed out in red on the top side of the PCB.
Solder the 10K 1/8W resistor to the top side of the PCB as shown.
Add the wire link on the underside of the PCB as shown.

That's it. Reinstall the board and enjoy trouble-free operation (now).

Regards,
Dave
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Re: XRef - 10MHz-Locked Reference Oscillator

Postby VK6OX » Tue Dec 11, 2018 7:24 pm

Resurrecting a long dormant thread!

First of all, thanks Dave VK3HZ for providing a solution to the XREF-VS unlock situation with the TS2000.

And now my question: has anyone used the XREF-VS with their TS590s or sg??

TIA
73
Andy VK6OX

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Re: XRef - 10MHz-Locked Reference Oscillator

Postby VK3HZ » Tue Dec 11, 2018 9:42 pm

Yes, the XRef-VS for a TS-2000 has been used on a TS-590S. The rig didn't have the optional TCXO but the XRef was to be always used with 10MHz supplied. Just change the output coupling capacitor to 47pF, inject at the TCXO output and you should get the right level. You'll need to break the power feed to the XO.

All you need to do is find a TS-2000 XRef-VS.
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Re: XRef - 10MHz-Locked Reference Oscillator

Postby VK4UH » Wed Dec 12, 2018 7:04 am

VK3HZ wrote:Yes, the XRef-VS for a TS-2000 has been used on a TS-590S. The rig didn't have the optional TCXO but the XRef was to be always used with 10MHz supplied. Just change the output coupling capacitor to 47pF, inject at the TCXO output and you should get the right level. You'll need to break the power feed to the XO.

All you need to do is find a TS-2000 XRef-VS.



Still a demand for your excellent X-ref design David!

As we have discussed before, a need for a second production run or maybe a Mk.2 one-size-fits-all version

Would you and your group consider another run or maybe even let someone else do it?

Seasons Greetings

KJ VK4UH
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