RayMarine SmartPilot X10 rategyro failure

[UP]

Hi,

I'm working through debugging an issue with my sailboat, the Bavaria Cruiser 47, 2001. This season the autopilot developed a new issue - RayMarine SmartPilot X10 main unit and Raytheon ST6000+ control unit - started giving rategyro failure at the control unit, dropping tracking/heading. Restarting it helped at times at the beginning of the season, but it became a constant and immediate failure at the end of the season. I changed my onboard batteries to LiFePo4 at the start of the season, but this should not have an effect, as per installation manual, the main unit's operational voltage is 10V-34V input and other SeaTalk/NMEA2000 instruments were working fine.

So, having a background in electronics, I'm working on debugging the circuit board. Does anyone have access to the service manual of the SPX-10? I have the service manual of SPX-5, but it is slightly different. The manual on the internet (https://www.manualslib.com/) seems BS (see image), as the voltage table just does not make sense as listed (no engineer on earth would name a testpoint node 5V and have the voltage behind this measure 3.2V-3.4V). Please see attached image of my PCB's test points below and list together with my readings (powered with 12VDC precision bench PSU, TP relative to 0V/GND of input, no peripheral devices connected):

• 0V-PLANE1: 0V
• 0V-PLANE2: 0V
• 5V1: 5.07V
• 5V-SWITCH: 4.99 V
• 5V2: 4.95V
• 3V3-STLK2: 4.99V
• 3V3: 3.31V
• 3V3-IPS: 0V
• VGATE: 11.59V
• VSUPPLY: 11.95V
• V2-CLUTCH: 11.94V

.

3V3-STLK2 at ~0V seems off, as does the 3V3-IPS at ~5V. Might just be that no peripherals are connected? Any ideas are welcome. I'll ask for a service manual directly from RayMarine too. The SPX-5 service manual is of some help, as I think they share a big part of the design.

EDIT: I've added an microscope image of the gyroscope IC itself. It is an obsolete Kionix KGY12 analogue gyroscope. Unfortunately I cannot find a datasheet for this IC. Does anyone by chance know the pinout or a drop-in replacement?

[elias]

Hi ! Passed something similar , check where is the fluxgate located , move it away from any cabling or motor . Mine was loosing heading , tried everything . Apparently was the new tap water pressure pump , (located on the other side of the bulkhead where the flu gate was located ). I changed it for a bigger , and every time it was working would mess the autopilot . Changed then the position of fluxgate and all back to normal .

[UP]

Elias,

Thank you for the input. The fluxgate compass is indeed a necessary device for the autopilot, but in this case is likely not the cause of error. Compass failure should display "no compass" or "no heading". My issue is with the rategyro, which is a gyroscope that measures angular rate of change of the boat. Compass measures magnetic heading. I have installed the compass rather far from any electric device, should not be an issue.

[Yngmar]

I have the SPX-10 service manual, but it also recommends that we come see Dave about his nonsensical voltages
Probably bad OCR when the table was formatted.

There is a rate gyro test procedure described on the next page that may help you:

Rate gyro
1. Using a DVM, measure the voltage at the rate gyro output (LTP13). If the rate gyro is serviceable, the nominal
reading is 2.5 V ± 0.3 V.
2. With the DVM still connected, turn the Course Computer slowly, first clockwise, then counterclockwise.
3. If the rate gyro is functioning correctly, the voltage should increase (from 2.5 V) as the Course Computer is
turned in one direction and decrease (from 2.5 V) as it is turned in the opposite direction.

Service manual attached.

[UP]

Thanks Yngmar, I have the same service manual, found it on the net. Besides the weird voltage references, the rategyro IC in the service manual is different from reality: KGY1SM in the manual, KGY12 on the actual PCB. I emailed Raymarine support (FLIR) with requests for a correct(?) service manual, IC datasheets and suggested replacements.

It'd be damned easy to do the decribed test, but the TP's are located on the other side of the PCB, they are very small, there are thousands and none of them are labeled!! So ... my present work is trying to figure out the pin mapping of the IC from the topside, getting there slowly.

[elias]

Mine didn't display any messages , just was loosing heading and course, good luck with the solution though
 

Elias,

Thank you for the input. The fluxgate compass is indeed a necessary device for the autopilot, but in this case is likely not the cause of error. Compass failure should display "no compass" or "no heading". My issue is with the rategyro, which is a gyroscope that measures angular rate of change of the boat. Compass measures magnetic heading. I have installed the compass rather far from any electric device, should not be an issue.

[SYJetzt]

Don't know your type of AP, but built myself an external gyrosensor for my ST6001 SG3. Used an analog gyrosensor with similar voltages like mentioned in your service manual. Sensor was on a breakout board in an external box.
My project was based on an article by a French sailor. See attached docs

[SYJetzt]

Soory, was unable to upload files from my android

[UP]

Update 1: my first assessment is that, very fortunately, the obsolete gyroscope KGY12 is OK and the actual culprit is the quad-opamp used for gyro signal conditioning: TLV2264 (see attached image). I'm going to replace this and see if anything improves. I'll update some passive filtering components too, just for kicks, on the input voltage node.

[UP]

Update 2: I received a reply from Raymarine who, basically, told me to bugger off, service manuals are proprietary and advised to buy a new autopilot. So that is a solid -1 on customer service. It is a well designed PCB and highly serviceable.

[UP]

Update 3: I replaced the quad-opamp TLV2264 today and per benchtop tests show the issue seems to have been solved.

I was getting heavily clipped low peak-to-peak voltages before on all of the opamp outputs, (ie 600 mVpp max), before the signal entered the main processing unit. Now I'm seeing rail-to-rail deflection 0V-3.3V (test points TP34 and TP35, integrator opamp outputs). See oscilloscope images attached below. I'm still disturbed by the noise in the signal, which is way less than before, so will look into it. Might simply be my oscilloscope leads (on long soldered wires) picking up switchmode noise from an adjacent circuit, might be the supply or passive circuits. Anyways, good progress made and I just might have saved myself 2500 EUR cash