Finding Short with New Flir One Pro iOS

[vestaviascott]

This is my first use of this camera. The treadmill is not sending power to the motor. Known good motor so I'm trying to figure out where the problem is. I just picked up a Flir One Pro and I have some pics below - my first time using it.

Here is the overall shot of the board powered on:

And here is a shot with the thermal sensitivity turned up to 165 degrees:

From the shot above, I'm thinking highly likely that the two hot spots above should not be that hot and likely are shorted to ground. One is a diode and the other marked "RG3" I think is a rectifier. Sound about right?

Here's the hot item at top, its marked "RG3" and sits between the 3 capacitors zoomed in:

And here's the hot item next to the large cap C7, its a diode marked "D4":

I was thinking my issue was likely a bad Mosfet together with a faulty diode on the large main heat sink rail, but neither of those are registering any heat signature. Does the FLIR pretty much conclusively tell us these hot components are likely shorted? And likely the cause of the motor not getting power?

 

[73's de Edd]

Sir vestaviascott . . . .


Well . . .I'll tell you whut . . . . .on that initial and first IR sensitivity settings resultant display. You probably could grip some ground plane metal on the pcb and release it and have it show your heat print, and then watch it quickly dissipate.

Now I was using the " cool " holes to navigate in relationship to adjunct parts on the second photo, but when you got to the parts photos, you were so close in that they no longer showed. Thereby I got lost.

As best as I could tell, one of the two hottest items footprints was the TO-92 cased semiconductor in your third photo.
Note that all components designations around it are all properly accounted for in respect to their silk screened on designations.
But that RG3 part is marked up with its silk screeing printings as compatible with two different case configurations. There is the outer perimeter ones outline which relates correctly to the TO-92 casing profile which is installed. Then there is the inner casing profile of a rectangular casing profile.
They relate to a parts list that has either a RG3 or RG4 assigned to, in accordance to the optional part being used. The TO-92 in our case.
Now put your eagle eyes to the casing of that unit and see if it doesn't have a 431 marking on it with an unknown prefix . .until you tell me . . .
of LM TL or K/KA.
That part they assign as RG3 . . . as in ReGulator 3 could run a bit warm, particularly if overloaded, since is an adjustable zener / regulator . . .IF you confirm that prior numbering on its case side.

Now your suspicioned other hot part, located lower down on the board, you point out as being that D4 diode.
Now if your pictures are taken in the same plane all of the times . . . . .that diode junction should look like a red dot.
Your pattern being shown, is a vertically oriented heat profile .
Look around and see if that is not actually being the hot heat sink tab of the TO-220 profile of a power transistor .
With its vertical spread ORANGE heat profile being akin to this . . . .

Does the FLIR pretty much conclusively tell us these hot components are likely shorted?

With their heat / orange , I would expect some decent power to be passing thru them . . . .if shorted I would expect them showing up as cold / blue.


Thaaaaaaaasssssit . . . . .

73's de Edd . . . . .



I had to give up jogging for my health, my thighs kept rubbing together and setting my underwear on fire.

 

[vestaviascott]

Thanks for the help. I can't get a close enough focus on that part to read the writing. I do have the schematic for the board. Here's an overall shot of the board in clear camera - I'll take a shot of the schematic next and post. The hot items are (1) top of the board between the 3 caps in a C shape and just to the left bottom side of the large capacitor:

 

[vestaviascott]

Here's a snapshot of the voltage schematic diagram:

 

[vestaviascott]

And here's a closeup of that Regulator:

 

[73's de Edd]

Sir vestaviascott . . . . .

Aaaaaaaaaah so . . . .the camera HAD been turned 90 degrees on the first photos diode shot, and it actually is being D4 , as the hot spot.
Also the 78L05 is being the TO-92 cased , 5 volt low power regulator . . .vice an LM431.
The heat sinked bottom corner DB1, is being the main rectifier for the high voltage DC supply which feeds into C7 main high voltage supply capacitor.
Now what you REALLY have supplied there is an interconnect wiring diagram instead of a full blown, totally informational schematic, so we will basically have to interpret functions by chassis parts appearances in their clusters.

We can initially see the right bottom corners M . .( DC motor ) is what grooooannnns in keeping the FAT lady moving on the treadmill.
If you are vewy-vewy caweful with your meter probes, you might check the 78L05 to confirm its powering situation.
Using the flattened front face of the units case for pin referencing the CENTER pin will be the negative ground meter probe point and then the RED meter probe will go to the RIGHT pin for incoming unregulated voltage of somewhat > > > 5V. Then the left pin will be the normally +5VDC regulated output.
Check it out !
Now its about time to ask WHAT, on the unit seems to light up or work, motorwwise and / or display wise ?
On your newest photo of the whole board, I can see the basic low voltage power supply for the units electronics, is being in the boards lower left quadrants cluster of components .
That is with the little yellow T2 as being the standby power transformer.
Just above it is a hefty D5 diode and its companion storage E-capacitor, just to its right.
If you could look under the board and see if the negative of the cap connects to a component that your probe could connect to from the top chassis side, then you could establish that ground connection . .TOPSIDE . . .and then reach over with the + meter probe and touch the banded lead of the big D5 diode and see if that power supply is putting out after plug in and power up turn on.

In the frontal foreground from the T2 power transformer there is being a minor finned, heat sinked power semiconductor. Can you provide its numbering, in order for my determining if that is THE whole self contained electronics of a SM power supply in a case, or is there being an ancilliary small 8 pin or mini flatpack IC that drives it . ( It could even be located on the other /bottom side, foil side of the PCB )
If the heat sinked unit only has 3 leads, I suspect the necessity of mentioned support I.C.
That IC would NOT be the cased unit at the 4 o'clock position from your hot D4 diode. I see that item as an optical isolator associated with the power triac on the board.
With two others side by side at board mid point and two minis at the very top board position.
Also, confirm if I am seeing two TO-220 cased Triacs / SCR's ? at mid point that are bolted together, back to back ?
So, I stop now . . . . . and let you fill in . . . .

Addenda . . . .
Also check, in referencing positionally to the LARGE C7 cap, as there are two major semiconductors on the heat sink just to that caps top and one minor TO-220 below the cap ( and possible others that the cap might be hiding ?)
Can you provide the part numbers, for those devices.

73's de Edd . . . . .

There was a power outage at our neighborhood department store yesterday. . . . . with upwards of twenty people getting trapped on the escalators.

 

[vestaviascott]

Thanks for all your help. The 4th photo is the one that is not same orientation as rest. That’s the d4 diode. I’ve actually left for few days vacation so I’ll try your suggestions when I return. Thanks again!

 

[vestaviascott]

Well . . .I'll tell you whut . . . . .on that initial and first IR sensitivity settings resultant display. You probably could grip some ground plane metal on the pcb and release it and have it show your heat print, and then watch it quickly dissipate.

By that can you clarify what you mean exactly? What areas are you suggesting to probe?

As best as I could tell, one of the two hottest items footprints was the TO-92 cased semiconductor in your third photo.

Yes. based on the 2nd high temp thermal image, the top element, marked RG4, and the bottom element, marked D4, are the hottest semiconductors on the board.

Now put your eagle eyes to the casing of that unit and see if it doesn't have a 431 marking on it with an unknown prefix . .until you tell me . . .
of LM TL or K/KA.

I got a better pic and determined that the part marking is LM 78L05 A624

Now your suspicioned other hot part, located lower down on the board, you point out as being that D4 diode.

Yes, with markings Z5 V1

Here are the pics in the same plane with overview shot and closeups of the two hot semiconductors:



Closeup of RG4:

Closeup of D4:

 

[vestaviascott]

If you are vewy-vewy caweful with your meter probes, you might check the 78L05 to confirm its powering situation.
Using the flattened front face of the units case for pin referencing the CENTER pin will be the negative ground meter probe point and then the RED meter probe will go to the RIGHT pin for incoming unregulated voltage of somewhat > > > 5V. Then the left pin will be the normally +5VDC regulated output.
Check it out !

Will do. Under power or not?

Now its about time to ask WHAT, on the unit seems to light up or work, motorwwise and / or display wise ?

Everything works as expected except the motor. Pushing the start button to start the motor, or pushing any of the speed buttons to do the same has no effect on the motor. However, when powering the unit on and pressing start, I can get the motor to spin for about a second. Like a surge of power gets to it but then stops.

If you could look under the board and see if the negative of the cap connects to a component that your probe could connect to from the top chassis side, then you could establish that ground connection . .TOPSIDE . . .and then reach over with the + meter probe and touch the banded lead of the big D5 diode and see if that power supply is putting out after plug in and power up turn on.

Unfortunately I cannot access the bottom of the board without removing the mosfets from the long heat sink rail. Depending on how involved that is I may be able to do it.

In the frontal foreground from the T2 power transformer there is being a minor finned, heat sinked power semiconductor. Can you provide its numbering, in order for my determining if that is THE whole self contained electronics of a SM power supply in a case, or is there being an ancilliary small 8 pin or mini flatpack IC that drives it . ( It could even be located on the other /bottom side, foil side of the PCB )

Printed on the top of the yellow portion is: R00512 on top and YNM3K; 1610057 on bottom

Also, confirm if I am seeing two TO-220 cased Triacs / SCR's ? at mid point that are bolted together, back to back ?

I'm not sure which area of the board you are referencing here. In reference to the large cap, could you orient the area?

Also check, in referencing positionally to the LARGE C7 cap, as there are two major semiconductors on the heat sink just to that caps top and one minor TO-220 below the cap ( and possible others that the cap might be hiding ?)
Can you provide the part numbers, for those devices.

From top to bottom, here are all the SCs attached to the heat sink. There are 4: