Electronic angle finder repair

[jman093]

Hi, just signed up. I'm hoping this is the right place to learn/help with electronics repair.

I have an an Kent Moore J-45059 electronic angle finder I'm trying to repair. This device clips onto a 1/2" drive extension and measures the angle it has been rotated to take the guessing out of tightening torque-to-yield bolts. When it reaches the angle spec that the user input, it beeps and also flashes an LED. These things are incredibly useful and are not cheap.

The unit powers up fine, the three buttons work, LCD works, and beeper works. What does not work is the angle finding. When it is set and started, the unit stays at 0 degrees. I was guessing this device basically worked on an internal electronic compass. I recently repaired the wonky compass in my 1990 Grand Prix's electronic information center. I found a bunch of copper windings inside and assumed that must be where the compass got its reading since copper windings obviously had to be magnetic-related. I resoldered the windings' device's contact points on the circuit board and the compass in the unit works fine again. This device, however, has no windings.

I went around hitting all the solder joints hoping to get lucky with a cracked one somewhere, but no luck. I'm no expert, so I don't know where to go beyond that. I have a DVOM and an understanding electrical principles, so I was hoping someone could point me in the right direction.

Thanks, and here's pictures of each side of the device with its case off. The circular black thing is the audible beeper.

 

[(*steve*)]

How does it sense the angle?

 

[Gryd3]

How does it sense the angle?

The only reliable way that would make sense to me would be an accelerometer...
A compass of sorts would receive interference from ferrous metals nearby, a gryo has drift, so would not be used by itself.

The device in theory would take readings from two accelerometer axis and use a simple trig equation to get the angle. (Or would use a lookup table)

This is just my thought though... I cannot read many of the components, and there was no mention of any additional parts aside from the case...

 

[KrisBlueNZ]

A quick Google shows that they consist of two arms that pivot at the point where they join together. So I assume they have a rotary encoder at the join. But some photos would be very helpful.

 

[Gryd3]

A quick Google shows that they consist of two arms that pivot at the point where they join together. So I assume they have a rotary encoder at the join. But some photos would be very helpful.

That's what I get for thinking while I'm tired... this is for finding an angle from any given reference... not an angle to ground. I missed the fact that it clips onto the other part of the device.

A rotary encoder is likely, but so is the same measurement mechanic that digital callipers use. I am curious for more pictures though.

 

[davenn]

There doesn't appear to be any pins for the connection of external sensors

I suspect one or more of those small IC's is/are accelerometers

jman, we need more info from you

What are the numbers on ALL of the chips we can see ?

Dave

 

[jman093]

Thanks for the replies!

Here's a pic with chips labeled:

And on the other side, the metal encased "chip" is legible in the first pic, and the tall green one between it and the batteries is labeled:

CQ
400
M

 

[davenn]

OK

The LMC6482AIM ( NOT LMC64828IM) is an Op-Amp
The 93LC468 is a serial EEPROM
The AH2951CMB appears to be a micropower LDO V-reg

I cant find any reasonable reference for the metal canned CCX2
I had assumed this was the crystal for the PIC clock but I'm starting to doubt that

The tall black item between it and the battery may well be the crystal as its connected to the appropriate oscillator pins of the PIC chip
Its quite possible that the CCX2 is a sensor ??

further searching the name on that part ... TOKIN..... appears to be within the NEC company
searching for a CCX2 on the NEC-TOKIN site didn't produce results


Dave

 

[KrisBlueNZ]

What are the markings on the tall black or green thing between the battery holder and the part marked Tokin?

When the board is fitted into the enclosure, does anything make contact with it? Perhaps with the four pads along the top edge? Can you show us a picture of the whole unit with the board put back in its proper place?

 

[davenn]

What are the markings on the tall black or green thing between the battery holder

CQ 400 M

and the part marked Tokin?

CCX2



Dave

 

[KrisBlueNZ]

CQ 400 M

Thanks Dave, I missed that. It could be a 4.00 MHz ceramic resonator but I have my doubts. Tokin do make crystal oscillator modules, but they make other things as well, so the tin module could be something else.

We need to see some more close-up photos.

 

[OLIVE2222]

The Tokin is probably the angular position sensor, I have doubt, as Kris, about the 4 Mhz resonator option because of is bulky size.

Here a link with related products:
http://www.nec-tokin.com/english/product/piezodevice2/ceramicgyro.html

Olivier

 

[davenn]

The Tokin is probably the angular position sensor, I have doubt, as Kris, about the 4 Mhz resonator option because of is bulky size.

Here a link with related products:
http://www.nec-tokin.com/english/product/piezodevice2/ceramicgyro.html

Olivier

careful, you are talking about 2 different things in the same sentence, makes for confusion

Yes that was my thoughts after visiting the NEC-TOKIN www site yesterday
The CCX2 device fits in with what I saw and you linked to

Dave

 

[davenn]

Thanks Dave, I missed that. It could be a 4.00 MHz ceramic resonator but I have my doubts.

I pretty much guarantee its a crystal resonator of some sort, as I said yesterday, its directly across the osc pins of the PIC chip

Dave

 

[Arouse1973]

I think you right Dave. CQ make ceramic resonators. The other part I am pretty sure is a ceramic Gyro. Found something similar.



Adam

 

[davenn]

yeah pretty cool, I didn't know those things existed till I googled TOKIN yesterday and got the NEC-TOKIN connection and visited the site
The one Olivier found later on

Gear I work on has angle sensors too, unfortunately the actual sensor is buried in a potted core
so I have no idea of the actual device


cheers
Dave

 

[OLIVE2222]

careful, you are talking about 2 different things in the same sentence, makes for confusion

Oups, Yes the angular sensor is the Tokin part and the overmolded black part between the battery holder and the Tokin is the 4MHz resonator.
Except the Tokin itself they are very few parts prone to fail in this angle finder. The OP can check for a signal on the LMC6482 pin 1 and 7 and on the corresponding ADC input of the 16LC72 PIC (pin 2 to 4)
Olivier

 

[jman093]

Well I came to the right place. Thanks everyone.

Oups, Yes the angular sensor is the Tokin part and the overmolded black part between the battery holder and the Tokin is the 4MHz resonator.
Except the Tokin itself they are very few parts prone to fail in this angle finder. The OP can check for a signal on the LMC6482 pin 1 and 7 and on the corresponding ADC input of the 16LC72 PIC (pin 2 to 4)
Olivier

Sorry for being a newb, but I'm gonna that spelled out a bit more. Not sure if this is how I'm supposed to check it, but pin 1 and 7 of LMC6482 have nothing with a voltmeter. Just 1mV and 13.1mV respectively. The latter part I really don't follow you.

 

[OLIVE2222]

You will find here under the 6 connections to be checked. All measurements are to be done with the negative probe connected to the ground.

Please report the 6 values with the arm mounted for min, middle and max angle:


LMC6482 Min Mid Max
Pin1
Pin7

PIC16LC72
Pin2
Pin3
Pin4
Pin5