Saturday, February 27, 2016

BRUNO Typhoon C3


I was helping a friend out this week with a project that will hopefully make life a little easier for the next person.  His fiance died last fall after losing a battle with bladder cancer, and they had gotten a mobility scooter from a friend to help her get around in the last months of her battle.  Unfortunately, it had been stored outside in a barn and wasn't working when they got it.  After some money spent at the "official" mobility repair shop and getting an answer that the batteries were dead and the motor seized and was "unrepairable", it sat in the back of a car for 6 months never used.  As my friend was starting to clean out and move on after his loss, I offered to take a look at it for him...

The unit was a BRUNO Typhoon C3 made in 2004, and apparently BRUNO no longer makes the scooters, just the lifts that move them in and out of cars, no repair manual available, and nothing to start from.  First things first, follow the power.

Under the rear faring
I removed the rear fairing and found the shop had "recycled" the batteries (wondering why it was so light).  So I hooked up a 24VDC/11A power supply for testing.  Turning the key switch for the scooter did nothing...  I removed the battery tray and disconnected the lead running into the 70A drive control.  Popping open the drive control, all looked good in there, with little more than some dust and dirt in the connection openings.  The battery harness was set up for connection to two 12VDC 18AH 1/2-U1 batteries, and wired so that there is a resettable circuit breaker between the cells.  Battery power runs down the drive control, and is paralleled at the 6-position connector there to supply power back to 18AWG wires for the steering column controls through an 8A fuse, which was good.

As I dug into the driver controls, I noticed that I could get a very faint and momentary beep out of the horn.  As I removed the control board I checked the key switch, which was fine.  One trace didn't look very good.  and it was the power coming off the key switch.  I took the board downstairs and sure enough, didn't have continuity.
Corroded power trace (under 5X microscope)

Trace repair with pink wire.  Key switch connector is yellow.

I took the board back out, installed everything, and now the unit powered up, battery meter read out, and horn worked.  The drive wouldn't do anything more than click.

I removed the axle/transmission/motor unit with the four bolts, and removed the motor (two M6x60 bolts, one of which was missing from the "official" repair shop).  I removed the the safety clutch with three screws and found that indeed, the motor shaft was stuck.  A pair of channel locks and relatively little force broke it free.  I removed both brushes, the lower was a little stuck, but seemed to be in good shape, as was the commutator.  Once reassembled without the clutch, I juiced it with 24V and it spun.  A quick trip to local hardware store (the HOMETOWN one, not big box, have to say I love that place for one-off small nuts and bolts!!!) got me new motor mount bolts for $2.86.  Put it all back together, and it runs!!!  A stop over to BatteryOne got me two new batteries for $84.70 with tax (not $300 like the mobility store was going to charge my friend!).

Darn thing works like a champ now.  Hopefully the next person can get some use out of it and make enjoying life a little easier.

Monday, February 22, 2016

USB or not USB... that is the question...

I had a friend from my son's school stop me last week and ask about an external hard drive that had broken.  I told him to bring it in and I'd take a look at it.  When he brought it in, the problem was obvious, the super speed microUSB jack had broken off the PCB in the docking base and was still attached to the USB cord.  Not good.  He said the best he could find to replace the dock was about $100 on eBay.  I told him I'd take a look, but I thought it might have ripped the traces off the PCB.

The unit was a Seagate external backup with a base unit that gets power and USB connection, and presents an SATA connection to a cased hard drive that plugs on top.  The base unit conveniently just popped apart with a little prying around the edges and revealed the PCB inside with three #0 Philips screws to free it from the case.

Detached SS microUSB (long thin 10 contact connector)
A quick look under the 5X stereo microscope showed all the traces were still good, and that the socket that had come off the board did not appear to have been soldered properly on the shield to board connection, likely a cold solder joint from inadequate reflow profile.

I was able to remove the microUSB SS connector from another board I had, using the Master heat gun and a Weller Pyropen, and was able to insert it into the PCB with a 15W pencil tip to heat up the case ground tabs to get it through.  I need to solder each individual connection as well, again with a 15W pencil tip under the microscope and keeping the tip just wetted with 0.022" rosin core and letting the solder on the socket and PCB wet together.

Final test with a spare SATA 2.5" hard drive here, and presto, looks like all the connections are good and the little bugger works again.  MAYBE, a $0.30 part if I hadn't been able to poach one, and 20 minutes.

Monday, February 15, 2016

Got a loose screw? VIBRA-TITE

We've loved our New Holland TC29DA compact tractor since we got it back in 2005, it's been a real workhorse for moving dirt, rocks, snow, gravel, trees, etc...  But it's had one nagging problem since about 2010...  The transmission case bolts that separate the HST from the clutch casing habitually get loose and back out.    The tell-tale sign is that it starts leaking hydro fluid while parked, and when under heavy hydro load, will actually spray out from the loose case seal.

The dealer says he's only seen it on tractors that use a 3-point hitch backhoe, but our backhoe attachment is the New Holland brand that utilizes a subframe to transfer some of the force up to the front frame under the loader.

So far we've tried;
 - re-torquing the bolts (#21 in picture, but installed from the front)
 - removing all accessible bolts, cleaning the holes and bolts with brake cleaner/degreaser
 - applying medium-strength blue thread locker to all the bolts
 - buying new case bolts with new captive lock washers and replacing

All have failed and come loose again in between 10-50 hours of use.

This time we went for the proverbial belt and suspenders approach.  I replaced the M10x30 bolts with grade 8.8, each have a polyester spray locking patch.  They've also been coated with VC-3 grade Vibra-tite, a non-curing acrylic gel (dissolved in MEK) that prevents any vibration loosing as the material stays in a soft and cold-flow state.  The bolts are then kept under tension with Belleville cupped spring washers, that apply about 550lbs of work load when flattened.

Original bolt on left, replacement on right

Get ready to work a bit putting the new ones in, they have to be cranked all the way in as the VC-3 cold flows under work load, but it does feel secure.  I'm feeling pretty confident that'll hold it in as I watch the snow pile up once again outside the window...

Monday, February 8, 2016

HP JetDirect 615n Reflow and Snow damage


Couple good ones this time...

I regularly help out at my son's school with computer issues, and the teacher there gave me an interesting one Friday.  An old HP LaserJet 2300 lost network connection, and she said there were consistent failures with these HP JetDirect 615n networking cards in the printer.  She wasn't willing to give up on the printer since they are bullet-proof and very cheap to operate in a school setting... so I dug in.  Apparently there is a know issue with the 615n cards (and many other current-day BGA-attached processors for that matter) the cards suffer from either a poor solder job on the main ARM processor or were poorly designed thermally that repeated cycling of the processor package results in solder contacts breaking from the ball-grid array under the main chip.

I took the cards home and  removed the plastic and metal shield around the network connector.
I prepped a lab ring stand with clamps to hold the boards 4" above a 1000F Master heat gun, the temperature control (air-throttle) was set to about halfway closed.  I mixed a little plain paste-flux into 91% isopropyl alcohol and dropped several drops around the perimeter of the main chip.  I placed the boards in a 130C (265F) oven for 4 minutes to pre-heat the board and drive off the IPA and water.  Turn on the heat gun, pull the board out and clamp it with the heat gun centered on the back side of the PCB below the main chip.  I tracked the temperature of the chip from the top with a cheap IR point-and-shoot temperature gun.  In about 90 seconds it ramped up to 200C.  I pulled the heat gun and aimed it carefully at the main chip for about 30 seconds to reach ~220-230C.  Then put the heat gun back below the board and switch it to fan only for about 2 minutes which cooled it back to 70C or so.  I ended up doing this on two cards, and both began operating in the printer again.  Personally, I was amazed.

 This is a test board where I successfully desoldered an 80 pin QFP chip to test the method before hitting the boards.
My other project was on my own roof.  The recent east coast snow storm dumped 38" at our house.  This time the snow catchers saved the gutters (which were trashed in the 30"+15" incher in 2010), but apparently the weight of all the snow melt sliding down my 10/12 pitch roof and solar panels was too much for the transition boxes to take the wiring to conduit.  Both boxes were ripped free of the roof and rolled over, snapping a 1/4" fiberglass tab on all four corners.  I was able to re-drill new holes and reattach, but even some of the MC2 connectors had pulled free of the module wiring.  This too some 3/4" poplar foot pegs to allow me to Spider-man/rock climb up the 10/12 pitch and reconnect wires that were two-thirds of the way up the slope...  this transition box system is going to get a re-design in the coming months...

Fiberglass box ripped off the S-5! clamps & conduit
Start Spider-Man!  My wife was kind enough to photo
for the insurance claim/hospital visit.
Where did that wire go!?!?!




Friday, February 5, 2016

Xerox Phaser 8560 pre-heater error

Special edition...

I've always been quite enamored with the Xerox Phaser solid ink printers for some reason, very cool idea and no toner mess...  You can likely find them cheap used, I picked up 3 for under $40 each.  The 8500 series, is very fixable, service manual being online, and only two torx screws needed to open the thing up.

I had an 8560 with a pre-heater error.  After swapping the pre-heater with another printer and still getting the same error 37,008.44, a nice person said it might be a fuse.  http://www.fortwayneprinterrepair.com/wordpress/2012/05/24/37008-44-error-xerox-phaser-8400/

About 6 plugs and 16 screws later, I'm inside the electronics package and sure enough, one of the 10A fuses is out, F3 in my case.  Popped a new one in from a broken spare printer (one of the 10 driver chips on the print head itself finally died, I think from overheat due to ink spillage and someone moving a hot printer!)  and re-assemble, the darn thing works again.



Enough for now...

Montana 2740 tractor and 2013 Nissan Pathfinder Drivers Door Handle

With the recent 38" snow here in Maryland, I had a chance to fix a bunch of stuff around the neighborhood:

A neighbor's Montana 2740 compact tractor snapped off the loader valve handle... drill it out and tap it to 5/16" thread and used a new piece of all thread to get it working.

My son continues to bring home reading books for homework that are paperbacks with pages falling out.  PLEASE DO NOT USE Scotch Tape!!!  Best thing to do, unfold/uncrease the pages as best as possible and use a SMALL amount of Elmer's glue along the spine to set each page that's fallen out back in, then rejoin the outside cover/spine with a strip of clear packing tape.

Door handle break on a 2013 Nissan Pathfinder like our did in the recent snow?   Pull on it and it doesn't spring return and just flops around.   Don't send it to the dealer for a $115 evaluation fee + repairs.  Get a Philips screwdriver, metric socket, and plastic automotive pry tools...
    The small plate behind the chromed (PLASTIC!!!) door handle pops out from the hinge side, remove the screw there.
    The back plate inside the armrest door pull pops out from the top with three catches, remove the two screws there.

    Pop out the kickplate light in the bottom of the door panel, disconnect the light.
    Pop out the window/lock controller from the armrest, disconnect the three plugs there.

    Pull the door panel free of the door starting from the bottom near the hinge side/speaker, work across the bottom and up the latch side.  The top corner near the side mirror is a hook that the panel hangs on.  Disconnect the plug going to the seat memory controls.
   Disconnect the door handle from the panel with 3 screws.
   Disconnect the door lock and latch cables from the BROKEN handle.
   Install the new handle part from your local Nissan dealer for ~$15.
   Re-install everything in reverse order.
   THE CATCH IS KNOWING WHERE TO PRY TO REMOVE THE FIRST TWO COVERS.   The service manual just says "remove the escutcheon using a suitable tool".  What the heck is an "escutcheon" anyway!!

p.s. Surpirse, the door handle has been redesigned to strengthen the door opener catch for the cable, just where ours broke!