Logitech Momo Black Racing Wheel Mainboard schematics?

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Hendersonville, North Carolina USA
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I have a Logitech Momo Racing Wheel ( Black ) and I am looking for the mainboard schematics / diagram... Basically I need to know which capacitors go where, etc...

It stopped working; I found lifted traces so I resoldered power and a few other things but my heat gun blew off a cap or 2 so I need to know which caps go where to doublecheck...

To start the wheel worked flawlessly until I put it up for a month or so.. I plugged it back in and nothing which is when I found the power wire had lifted a trace. Once I resoldered that the lights would come on but would be very dim and would flicker.. If I held the gas pedal down to max and plugged it in and then released the pedal then the light would be brighter but not at full capacity. so I checked both boards for bad connections and found none. One cap looked burnt so I was desoldering that when another came off but I still need to know what goes where and a full schematic / diagram will help me in the debugging and repair process...

The board in question is: 201603-A000 REV.A0 E-UH9/Bobcat main BD
on another side of the board: Backwards R attached to U CHI SHENG 94V0-33

I have looked all over but have had 0 luck in locating the schematic / diagram so any help is much appreciated!



I am waiting on a broken g27 to come in - which likely has a loose screw for the calibration or bad calibration wheel - so if anyone has full board schematics for this too, that'd be amazing!

[ SOLVED ]
 
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Can you post (good) photos of the board? I don't have a Momo board to reference but it might help figure out what they do. @mrbasher and @eKretz are probably the best people to ask. Do you know the values of the caps that came off, or are they lost?

I am waiting on a broken g27 to come in - which likely has a loose screw for the calibration or bad calibration wheel - so if anyone has full board schematics for this too, that'd be amazing!

I've been working on mapping my G27 board, but I wouldn't hold your breath on it being finished any time soon, and to make matters worse none of the SMD caps are actually marked and I'm not about to desolder each one to test it! But yeah, if you can find out what the caps are for by looking at what they're connected to, you can make an educated guess. Generally speaking on low frequency or power lines you don't have to be precise at all, but on an I2C, SPI or USB bus you do have to be more accurate - but you can probably find out what those capacitors should be as they'll normally be ubiquitious.

Also as an aside, the backwards RU mark is this: http://electronics.stackexchange.com/questions/226521/what-does-ru-ur-label-on-dc-power-relays-mean
 
Thanks for the response!

The cap is lost... but I was able to fix the board and the unit now works perfectly!

On top of the issues with the detracing and depadding at the power-pins, I found the same issue in another spot.. On top of that the fuse was bad ( finally repaired my voltmeter so I was able to test for continuity and test the other components on the board )..

My resoldering of the lifted traces didn't originally hold up because I didn't see that the pad had lifted too - the color of the board is very similar to copper and in one spot where I scratched off a bit of the trace it looked like I went through the copper... that's how close the color is and I have 0 deficits in terms of color-blindness .. most men have issues seeing the full range of colors, something I am not afflicted with and the color was still next to identical to copper - which is one of the reasons why it'd flicker and the poles just kept coming out so I scratched off a bit of the lead which was connected to the pad before it was gone and I also scratched off a bit of the global ground and soldered the pins to the newly exposed copper.

I replaced the cap with a 4.7µF 08x04 cap instead of 06x03 ( because Farads on caps is simply how much energy they can store and Voltage is the level of insulation - something I completely lapsed about - so it didn't really matter which one I put so long it has enough energy and the 10µF caps I ordered haven't come in and 10µF is the max or close to the max size for small surface mount caps )

I bypassed the fuse for now until I can locate a replacement, or I'll use an equivalent I have on hand - I soldered headers to make swapping in a new fuse easier.. I have been running the wheel as is ( I run all my electronics on UPS' and the fuse on the board was likely to prevent a surge from thunderstorm or if the power supply broke - I am planning on putting a fuse in but for now the unit is working perfectly from what I can see - I still need to test a few other games - only tried spin tires and the force-feedback is lacking severely in that tech-demo )

The fuse is ( Photo taken with my cheap usb microscope - wording is so small that it is difficult to read with the naked eye and the ps part wasn't legible to me otherwise ): ( JET Fuse 1A 395 Series PS E ) https://www.dropbox.com/s/zyyvozggg04oa5a/JET Fuse 1A 395 Series PS E.jpg?dl=0

For future reference, here is a photo of the board ( top only - I'll get a bottom photo later so people with the same issue can see how I fixed it ) and I am waiting on a G27 wheel to come in ( got it for $40 shipped and it needs a calibration wheel by the description of the problems the seller expressed ) at which point I'll probably sell the momo wheel along with a wireless xbox 360 wheel with pedals.

Board: https://www.dropbox.com/s/otpbgk0ncjlxurw/20170327_054852.jpg?dl=0 - Note: The brown wire on the left is the bypass lop for the fuse which I will replace as soon as I find an equivalent or the same one. The chip on the right looks dirt because I swiped over all of the solder-joints on the board which looked off such as those appearing to have cracks, cold-joints, etc... and I didn't have a good tip for the chip so I had to go over a few times and used a bit of flux to help, not to mention I used the heat gun in that area so the board darkened a little. C7 is the replacement cap and I'm not happy about the joint I made because it is a larger cap ( ordered wrong size so I am trying to get rid of them ).

I also noticed there are a lot of, or it looks like there are a lot of, missing silkscreen labeled caps, etc... not entirely sure what they're for; also, until I replace the fuse I'm keeping the cover off and for additional precaution I have in-line switches for power adapters so I have it hooked up so I can turn the power on / off with a simple switch...
 
According to this datasheet (figure 4, page 16) it looks like C7 is connected to pin 8 on the MCU, which is 'RESET. The note on page 13 reads:

Adding two 100 nF decoupling capacitors on the Reset pin (respectively connected to VDD and VSS) will significantly improve product electromagnetic susceptibility performance.

I know what you mean about the PCB's substrate looking just like copper, too, I've fallen for that one before!
 
Which data-sheet if you don't mind me asking? I was unable to find anything...

Luckily it seemed to only be that one cap though and since caps voltage is simply insulation and Farads being charge capacity I replaced it with a 4.7µF and it works...

I may do a small video on repairing it in case others have the same issue ( it is really strange that the headers came loose when the case had never been opened; probably temperature cycling, and hot/cold-solder-joint [ I've noticed when I solder more closely to the melting point of the solder, the shinier it is at the outcome - I solder 50C above melting point now -, and the hotter I go - I used to solder at 100 to 150C above melting - the more it looks like a cold-solder joint ] not to mention because of the rumble [ and no rubber stops or anything to protect the board from the vibration ] may have been the cause ) so they know where to start, and maybe finish... The data-sheet would be a huge help to that end.

Still waiting on the G27 replacement wheel to come in so I may end up selling the Momo wheel after making a few improvements ( adding rubber vibration absorbing material to protect the board and re-dust the internals as it has been open for a while ) unless I need a part from it to fix the G27...
 
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