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KI-207 indicator VOR center adjustment

Does anyone know which screwdriver is suitable?

There is a small potenstiometer behind the upper left screw that needs to be tampered with. Obviously something small, but is it hex, flat or philips?

G

The KI207 doesn’t have any adjustment screws – these are only in the KI203/204.

Have a look at the installation manual: http://www.seam-avionic.com/pdf/r09eng1yjo.pdf

If you in fact have a KI204, the adjustment screw is a flat blade – about 1.5mm wide will do and don’t push too hard or you’ll bend the legs of the potentiometer. A normal instrument screwdriver is too short so a piece of thin brazing rod filed to a flat blade works fine.

Last Edited by wigglyamp at 02 Jul 15:29
Avionics geek.
Somewhere remote in Devon, UK.

Thanks.

The indicator is NOT a KI207, you are absolutely right. So, which one is it? I have tried google, but it is a bit inconclusive.

G

That’s either a KI204 or KI206 – it will depend on what it’s connected to. What is the Nav system it’s coupled to?

Avionics geek.
Somewhere remote in Devon, UK.

There are two of them, each one coupled to a KX165. One of them can also take GPS, I believe.

They are both off, in opposite directions. The radios have the opportunity to show the radial in the display, and that number is surprisingly accurate. The indicators are a couple of dots off. Error seems constant on different radials, so worth a try adjusting the center/zero….?

G

OK – with a KX165 you’d normally have a KI206 indicator. The interconnect is as per page 2-25 of the installation manual:
http://www.aeroelectric.com/Installation_Data/Bendix-King/KX155_IM.pdf

If the VOR or ILS LOC are not correctly aligned, the adjustments are on the KX165 itself, not in the indicator. (The KI204 has the electronics for the Nav converter inside whereas the KI206 does not – if uses the converter within the KX165). If you remove the KX165 from its tray you’ll see the adjustment scews marked on the case under peel-off covers.

To make an accurate VOR adjustment requires a Nav test set to generate radials of 000 and 090 degrees. The normal adjustment is to centre the beam bar accurately on 000 and then halve any residual error on 090. Before doing this however, the digital bearing adjustment must first be set to as accurate as possible to the test set radial using the appropriate potentiometer on the KX165.
If you don’t have access to a calibrated test set, I’d suggest approaching your local avionics engineer or company to do these adjustments for you. If you try and do the adjustment using just one radial from a local station you have little chance of getting the system accurate across all bearings.

A further note. If you have a residual VOR error in the same sense on all bearings (perhaps always over-reading by 3 degrees), then most likely the resolver synchro in the indicator is misaligned. This will require setting up on the bench – it’s not something that can easily be done in the field.

Avionics geek.
Somewhere remote in Devon, UK.

You are probably right, this sounds like a job for the local avionics guy…

Thank you for your help,
G

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