Fishing trolley faulty....again

[scooby]

Hi Edd, we may be getting somewhere! To clarify, the irf3205 is the fet that i bought by mistake (carelessly)and have removed. The original fet was the mbr2010, one of which is still in situ.The irf3205 i pushed the pins back in place on the board and although not soldered in place the gate recorded the voltage as rising from 0v to 10.6v as the trolley was switched on and the speed control was operated.The mbr2010 in comparison records 12.8v at all times, even when the trolley is turned off.

 

[73's de Edd]

Sir scooby . . . . .

2 earlier edits . . . . that were precluded from my editing . . . . . . by a metered limit time out.

Indeed . . . in using the very first photo, it does reveal the in and out electrolytic decoupling filters and the center tab goes to that ground plane and one portion of the the regulator output power distribution, goes to the end BROWN wire of the boards end connector.

Most Honnable and Esteemed . . . Bluejets . . . Indeed . . . in using the first photo, it does reveal the in and out electrolytic decoupling filters and the 7805 center tab goes to that ground plane and at least one portion of the the regulator output goes to the end BROWN wire of the end connector.


With time and heat and compression, but no silicone grease, the transistor will stick to the membrane and usually tear if an attempt to remove the transistor is made.

With time and heat and compression, but no silicone grease, the transistor will stick to the membrane and usually tear if an attempt to remove the transistor is made. Then you can see the pulled off fine veneer of silicone film and then the core criss cross woven micro thin central fiberglass cloth mat that it was adhered to.
Looks just like the MUCH-MUCH-MUCH LARGER denier fiberglass cloth used on boat repair and Corvette body work.


Now, you say . . . . .

irf3205 is the fet that i bought by mistake (carelessly)and have removed. The original fet was the mbr2010, one of which is still in situ.

That MBR2010unit is NOT a FET but is being a dual power diode, an IRF3205 IS being a POWER FET and IS being the units power handling control element.
So . . . . . you must now have on hand, the units original IRF3205 plus the replacement IRF3205.

Of the two, the old original unit is being defective by DRAIN TO SOURCE TO GATE shorted out.
With a " runs at full breakneck speed " condition when installed.

The newer installed unit has now failed with a blown GATE, thus no response to the applied variable drive level.
(Thank GOOOOOOOOOOOOOODNESS . . . . for the confirmed variable drive level presence . . . . as that ST IC unit is being one COMMM-PLEX puppy internally.)

Talk to me . . . .

73's de Edd . . . . .

Old telephone directories make ideal personal address books . . .
simply cross out the names and addresses of all the people you don't know.

 

[scooby]

Hi Edd, just to try to clarify some more, i believe the irf3205 is still working as the voltage at the gate rises from 0v when the speed control knob is switched on and rises to 10.6v at full "power"and back to 0v when i rotate the speed control knob the other way......or am i missing something again. Thank's in advance for your patience

 

[73's de Edd]

Sir scooby . . . . .

(Switching into . . . . . "Der Captain Und Der Kids / Katzenjammer Kids " personna . . . .)

INTELLIGENTIA REFERENCING . . . . ( for the unfamiliar )

https://2.bp.blogspot.com/-sj6GT0jW...NlKxForiNCEL97_rV7gCLcB/s1600/Clipboard01.jpg

Vell . . . . I'm tellink yer vats . . . . .I'm' chust thinkinks dat der most newest IRF 3205, vot that you are bin havinks, is DEFINITELY " beink . . . .KAPUTS "

Und iffen yer wantink to be fixink dat dere ting . . . . hereswhatchagotttabedoink.

(Switching out of . . . . . "Der Captain Und Der Kids / Katzenjammer Kids " personna . . . .)

Firstly . . . . NO feed back was given as per the visual inspection of the case of the replacement IRF3205 at time of install, as now being compared to its present condition as per overheating discoloration ? ? ?

To answer for all concerns relevant to battery condition and state of charge as well as all major power carrying routing, just do this.
Place the unit up where the wheels are free of contact and therefore the sole loading will be the motor and the loading presented by the intercoupled gear train / wheels runout..
Place a short length wire jumper, being of at least the wire gauge seen being used as current shunts for sampling for the motor controller IC. Two are used on both the DRAIN and SOURCE of the POWER FET on both sides of the circuit board. Two on one side have short fiberglass tubing insulation lengths covering them.
The installed jumper is to be between the DRAIN and SOURCE leads of the POWER FET.
When you then switch on the unit, it should be running at "breakneck" speed, such as you have experienced once before.
This would confirm the battery and its state of charge being up to normal, as it would also confirm all power carrying circuitry /wiring / connections being made.
You just don't have a POWER FET with an intact GATE . . . . . .replace BAD POWER FET, with GOOD POWER FET..


73's de Edd . . . . .

We had to get rid of all of the kids. It turned out that the cat was allergic to them.

 

[scooby]

Hi Edd, now we're talking (hands up who else read the link ). Sorry about the lack of feedback regarding the irf 3205, the truth being i have no idea, i can't recall thinking about such things. I placed the jump as described above.....nothing apart from a tiny knock from the motor, so i think i had better check all leads and connections again. Now ,at this point you all might want to get in line to kick my butt, i do deserve it. Upon inspection of the fuse again, what i took to be a good firm connection was in fact a distorted fuse, fuse holder , appearing at a glance that all was well, the fuse being unbroken. With a couple of push and pulls the trolley is running normally again, the question now being, what has caused it to overheat? This comment from bluejets is gonna haunt me......"It is a common error for newbies to start to blame failed electronic components.
Mostly, the components are long lasting and faults occur in more common "mechanical" devices such as switches and connectors.
It is possible you never really corrected the fault from your first attempt.
That was why I asked you to check other things as above." I'm off now to hide behind the sofa!

 

[73's de Edd]

Sir scooby . . . . .


" CON-GRAN-U-LATIONS ! " . . . .at least, with that suggested thorough final troubleshooting procedure . . . when you found absolute minimal motor response . . . . with having the FET jumped . . . you then knew that you definitely " . . . . . had trouble right there in RIVER CITY " a la . . . 'lil Abner.

The fuse holder is just being two minimulistic / glorified push on connectors in a plastic housing. PLUS you are dealing with connections of 2 galvanically opposed metals of tin on copper to alum-a-in-ninny-yumyum.
Plus, geographically, I don't even know if you are additionally having to contend with detrimental salt water "vapors" versus being in optimal fresh water environs.

With time and current demands the two connections might have decreased effective surfactal contact area and developed even more current conduction , within a smaller contact area, leading to a hot spot / heat generation and further oxidixing of effective contact area.
Then the plastic usually distorts or even swells / bubbles to give you a clue of the ensued condition . . . . IF you ever noticed.

Ye Olde Shopping List . . . . one each . . . new fuse holder and fuse to replace the existing.
Then on install, plug in and unplug the fuse at least 5 times and place a trace film of silicone grease on the blades to carry in as you plug in 6 more times with a grease touch up each time. That will then carry in to the internal puish on contacts.
That will; give you both a moisture and fume barrrier from airborne oxidizing elements.

(Had this been my unit . . . to fix . . . I just would have replaced the fuse with a surplus derived, sealed aeronautical / military quality KLIXON circuit breaker . )


73's de Edd . . . . .

Some people think my brother is weird, because he has sideburns behind his ears.
Me . . . I think he's weird, because he has false teeth. With braces on them.

 

[73's de Edd]

Whassamattah me . . . . you noes i cans spels . . . minimalistic !

(Had this been my unit . . . to fix . . . I just would have replaced the fuse with a surplus derived, sealed aeronautical / military quality KLIXON circuit breaker . )
As were to have been found, lined up inside the cockpit of ye olde Huey Cobra.

AVAILIBILITY REFERENCING . . . .

https://www.google.com/search?newwindow=1&ei=rZfDXI-nE4aQtQX_8bugCw&q=+surplus+KLIXON+military+grade+circuit+breaker&oq=+surplus+KLIXON+military+grade+circuit+breaker&gs_l=psy-ab.12...21245.24379..28330...0.0..0.90.671.9......0....1..gws-wiz.......0i71.d0RbHKBdR20

 

[scooby]

Thank's, Edd, i'll order the relevant parts today, install them and report back!

 

[scooby]

Got my new mosfet, thermal grease and fuse, fixed the tab on the pot to stop over rotation,carefully silicone greased my fuse as instructed and my trolley is up and running again.Thank's to everyone for your input, it really is greatly appreciated. Edd, your a star, a special thank's to you for your patience and humor. Until next time, adios