No Beep

[flyboy0681]

Fresh out of its annual the plane is flying smooth, cool and well rigged. Although it's working just fine, the KAP 150 no longer beeps during it's self-test and when I disengage it via the thumb switch.

Where's the first place I should look in attempting to resolve this?

[carusoam]

Make sure the power trim switch is on...

Somewhere in the Annual process it gets turned off...

First flight back in the owner’s hands...

Owner expects the electric trim to always be on...

The BK KAP150 autopilot checks for trim power, then fails when it is off...

PP thoughts only, we have a good BK guy around here as well...

Best regards,

-a-

[flyboy0681]

Just now, carusoam said:

Make sure the power trim switch is on...

Somewhere in the Annual process it gets turned off...

First flight back in the owner’s hands...

Owner expects the electric trim to always be on...

The BK KAP150 autopilot checks for trim power, then fails when it is off...

PP thoughts only, we have a good BK guy around here as well...

Best regards,

-a-

I appreciate the response but the trim switch was the very first thing I checked, having been through it a few times before.

The A/P itself works perfectly and I even had it fly an LPV approach down to 200 feet (in VMC).

I suspect the wiring to the Sonalert became disconnected.

 

[carusoam]

Without the success beeps caused by a failed test... the AP probably can’t do anything...

If it is working... but silent...  sounds like it lost touch with the sonalert...

The only time I didn’t get success beeps was for the off position of the trim switch...  

Best regards,

-a-

[flyboy0681]

Just now, carusoam said:

Without the success beeps caused by a failed test... the AP probably can’t do anything...

If it is working... but silent...  sounds like it lost touch with the sonalert...

The only time I didn’t get success beeps was for the off position of the trim switch...  

Best regards,

-a-

When my switch is off it beeps ten times. That's all it takes to get my attention.

[Awful_Charlie]

Do you have a KA15 aural alerter? It can be wired in two ways, either through the intercom/panel or via a sonalert. I had a similar problem and it turned out to be the KA15 itself, but was a cheap fix (can't remember exactly how much, so probably less than 0.2AMU)

[flyboy0681]

Just now, Awful_Charlie said:

Do you have a KA15 aural alerter? It can be wired in two ways, either through the intercom/panel or via a sonalert. I had a similar problem and it turned out to be the KA15 itself, but was a cheap fix (can't remember exactly how much, so probably less than 0.2AMU)

I have no idea what a KA15 is, but the Sonalert was never heard through the intercom, only through the ceiling.

[Warren]

Here is some information -- caution all from at 1985 M20K, 12V system -- that is hopefully similar to what you have. 

If you have only the sonalert and not the KAA 15 the information below may help.  It is either a power or grounding issue and these are very simple circuits.  Power is supplied directly to the sonalert and grounded through the autopilot to create the alarm.

First - check if you have 12V at the sonalert.  If not, you know there is a power supply issue or an open breaker and can chase that down.

Second - check if you have a connection between the ground side of the sonalert and the autopilot.

Here is the drawing for the connector that leads up to the ceiling panel (at least for the M20K).  It goes down the pilots side a-pillar and enters the dash near the ignition switch and the connector is not too far behind.  Not shown are the sonalerts for the autopilot that are optional and almost identical to the stall and gear horn.  With my autopilot, the Trim fail power (pin 11) supplies power to both sonalerts (the power is tied from the + side of the trim sonalert to the + side of the A/P sonalert).  The individual sonalerts are grounded through pin 12 and pin 15 depending on which sonalert is triggered.  Hopefully through this connector you should be able to see if there is power and when you run the autopilot test, see if the grounds are being switched to sound the sonalert.

Good luck and hopefully this helps a little.

[flyboy0681]

1 minute ago, Warren said:

Here is some information -- caution all from at 1985 M20K, 12V system -- that is hopefully similar to what you have. 

If you have only the sonalert and not the KAA 15 the information below may help.  It is either a power or grounding issue and these are very simple circuits.  Power is supplied directly to the sonalert and grounded through the autopilot to create the alarm.

First - check if you have 12V at the sonalert.  If not, you know there is a power supply issue or an open breaker and can chase that down.

Second - check if you have a connection between the ground side of the sonalert and the autopilot.

Here is the drawing for the connector that leads up to the ceiling panel (at least for the M20K).  It goes down the pilots side a-pillar and enters the dash near the ignition switch and the connector is not too far behind.  Not shown are the sonalerts for the autopilot that are optional and almost identical to the stall and gear horn.  With my autopilot, the Trim fail power (pin 11) supplies power to both sonalerts (the power is tied from the + side of the trim sonalert to the + side of the A/P sonalert).  The individual sonalerts are grounded through pin 12 and pin 15 depending on which sonalert is triggered.  Hopefully through this connector you should be able to see if there is power and when you run the autopilot test, see if the grounds are being switched to sound the sonalert.

Good luck and hopefully this helps a little.

This may be what I'm looking for, thanks.

Does the whole ceiling panel have to come off for access?

[Warren]

Here is some information -- caution all from at 1985 M20K, 12V system -- that is hopefully similar to what you have. 

If you have only the sonalert and not the KAA 15 the information below may help.  It is either a power or grounding issue and these are very simple circuits.  Power is supplied directly to the sonalert and grounded through the autopilot to create the alarm.

First - check if you have 12V at the sonalert.  If not, you know there is a power supply issue or an open breaker and can chase that down.

Second - check if you have a connection between the ground side of the sonalert and the autopilot.

Here is the drawing for the connector that leads up to the ceiling panel (at least for the M20K).  It goes down the pilots side a-pillar and enters the dash near the ignition switch and the connector is not too far behind.  Not shown are the sonalerts for the autopilot that are optional and almost identical to the stall and gear horn.  With my autopilot, the Trim fail power (pin 11) supplies power to both sonalerts (the power is tied from the + side of the trim sonalert to the + side of the A/P sonalert).  The individual sonalerts are grounded through pin 12 and pin 15 depending on which sonalert is triggered.  Hopefully through this connector you should be able to see if there is power and when you run the autopilot test, see if the grounds are being switched to sound the sonalert.

Good luck and hopefully this helps a little.

 

Update:  The harness connector for the ceiling panel should be accessible under the instrument panel.  The other end is at the sonalert.  You can get to them by removing the sonalert speaker cover (two covers - pilots side is the speaker, co-pilot is sonalerts).  However, you cannot pull out the little metal subpanel as the 4 sonalerts will not fit through the hole.  You can open up the panel with the overhead light switch, reach in and hold the back of the sonalert while you unthread the outer portion.  Once two sonalerts are removed, the metal sub-panel can be removed giving you full access.

1.  The easiest access may be to the connector under the dash.  Probably zip tied with about a dozen other connectors.

2.  The most reliable access is the sonalerts but requires some disassembly of the ceiling panel -- not too bad except getting the sonalert cap to thread off which can be very difficult with the plastic threads that tend to be very sticky.

Here are the connections to the back of the autopilot if you need to check the grounding.

 

The ground connections I think you are looking for are Pins L, M and N.  Normally open, grounded to make the sonalert sound.  I think M is for the KAA 15 -- not positive but hopefully this also helps.

[flyboy0681]

6 minutes ago, Warren said:

Here is some information -- caution all from at 1985 M20K, 12V system -- that is hopefully similar to what you have. 

If you have only the sonalert and not the KAA 15 the information below may help.  It is either a power or grounding issue and these are very simple circuits.  Power is supplied directly to the sonalert and grounded through the autopilot to create the alarm.

First - check if you have 12V at the sonalert.  If not, you know there is a power supply issue or an open breaker and can chase that down.

Second - check if you have a connection between the ground side of the sonalert and the autopilot.

 

This is getting a bit more complicated. Let me ask you this, at the annual my partners and I requested that the interior light bulbs be removed. Would you see any reason why doing that would lead to the Sonalert being disconnected in the process or was it a coincidence that it stopped working for the last time when I was on approach to the airport dropping the plane off?

[Warren]

Should not be related as the light bulbs are not part of the sonalert circuit.  And, the lights are wired directly to the battery and not through a breaker panel so they are available then the master is off.  Here is a bigger picture of the wiring diagram showing the lights in the ceiling panel as well.

The ground from the gear horn is used for the ground from the lights and the power is supplied from the battery through the same feed as the clock.

The autopilot sonalerts have no connection and should not be affected but this circuit.  Especially if only the bulbs were removed from the lights and the wiring was left in place.  Access to the bulbs is from the light covers and not related to the sonalerts.