Sourcing Diode/Equivalent: MOSPEC U15A60 (anode on left)

[theflyingaj]

i am a newbie troubleshooting a motor control circuit board (PCB230D002F) for a treadmill. symptom was that the treadmill belt would not run. i have been replacing components that tested bad on the heat sink panel.

(the 90v/4 hp dc motor that runs the treadmill belt tested good.)

items tested bad and replaced:

bridge rectifier:
original: MP3510L (failed/short circuit between pins)
replaced with: MP3510 (with modified heat sync mount and jumper wires, i couldn't find a compatible one in the same configuration)

mosfet:
original: IRFP250N (failed/short circuit between pins)
replaced with: IRFP250

right now i have tested the heat sinked diode which is bad:
original: mospec U15A60 (failed/open circuit between pins both directions)
anode(+) on left / cathode (-) on right (viewing pins down, heat sink to rear)





my issue is that i cannot find an equivalent diode within the united states where i can verify the correct polarity on a datasheet. the closest one i found had the cathode marked with a (+), so i don't trust that information.

i prefer to order off of amazon or ebay, but will order from manufacturer/distributor/reseller as long as it's within the united states.

some cantidates i came across for the diode:
MUR1560
VS-HFA15TB60PBF
NTE6248

i have not been able to confirm desired polarity on any of these. i just want to confirm that it's the correct one before i make a purchase.

i have a very busy work week so it isn't easy to just call up the major electronics superstore websites and haven't had any luck emailing yet. (one didn't have the correct polarity, another hasn't hasn't had their tech email be back yet)

i have also removed the single large cap on the board and it tested good. the other diodes on the board i didn't remove to test, but seemed to test out ok.

i don't have a strong electronics background, but i hate to buy a new board for hundreds of dollars over a fried component that costs five bucks.

any thoughts/advice would be most welcome.

[petehall347]

Re: Sourcing Diode/Equivalent: MOSPEC U15A60 (anode on left)

might be from before someone decided the + and - are switched . ?

[petehall347]

Re: Sourcing Diode/Equivalent: MOSPEC U15A60 (anode on left)

they swapped polarity by suffix .. trouble is there is no suffix on yours http://html.alldatasheet.com/html-pd.../1/U15A60.html

can you not trace the circuit ?

[petehall347]

Re: Sourcing Diode/Equivalent: MOSPEC U15A60 (anode on left)

cathode will be plus will it not ?

[budm]

Re: Sourcing Diode/Equivalent: MOSPEC U15A60 (anode on left)

+ is Anode, and according to the spec sheet pin1 is also tied to pin 2 (tab),m verify that to make sure since it is not Iso-tab TO-220 casing. 3 is Cathode. Hard to find sub with pin 1 connected to pin 2 for Anode.
https://cdn.badcaps-static.com/pdfs/...28f7c07cc6.pdf
EBAY?
https://www.ebay.com/itm/5pcs-New-U1.../182164953269?

[theflyingaj]

Re: Sourcing Diode/Equivalent: MOSPEC U15A60 (anode on left)

they swapped polarity by suffix .. trouble is there is no suffix on yours http://html.alldatasheet.com/html-pd.../1/U15A60.html

can you not trace the circuit ?

the + and - are labeled on the picture, problem is that the ones i find online are backwards, (- on left, + on right) and i cannot flip the diode around due to the heat sink plate on the back. i am trying to order one from the united states instead of waiting a month to get one from china.

[theflyingaj]

Re: Sourcing Diode/Equivalent: MOSPEC U15A60 (anode on left)

they swapped polarity by suffix .. trouble is there is no suffix on yours

can you not trace the circuit ?

+ is Anode, and according to the spec sheet pin1 is also tied to pin 2 (tab),m verify that to make sure since it is not Iso-tab TO-220 casing. 3 is Cathode. Hard to find sub with pin 1 connected to pin 2 for Anode.
https://cdn.badcaps-static.com/pdfs/...28f7c07cc6.pdf
EBAY?
https://www.ebay.com/itm/5pcs-New-U1.../182164953269?

i've looked at that data sheet already and saw that china listing on ebay, trouble is that i don't want to wait a month to get one from china. i was hoping to buy an equivalent one from the united states, but can't verify one with the right polarity so i can install it directly to the heat sink plate without modifications.

i assume the suffix on my piece would be U15A60-R



(it seems odd that in the data sheet the anode connects to the heat sink screw which is straight to ground.)

[budm]

Re: Sourcing Diode/Equivalent: MOSPEC U15A60 (anode on left)

"(it seems odd that in the data sheet the anode connects to the heat sink screw which is straight to ground.)"
So there is no insulation sheet, washer to isolate the tab form the heatsink? You need to trace out the circuit then to see how the Anode is connected in the circuit. Is the heatsink is actually connected to the circuit ground?
May be you should up load good clear pictures of the whole top and bottom side of the board showing all the damaged parts.

[theflyingaj]

Re: Sourcing Diode/Equivalent: MOSPEC U15A60 (anode on left)

so i purchased this item on ebay as earlier suggested:
https://www.ebay.com/itm/5pcs-New-U1.../182164953269?
turns out that the item that arrived was reverse polarity than the one pictured. all that time waiting for the shipping from china and they sent me the wrong one.

http://oi64.tinypic.com/f50tvr.jpg

[R_J]

Re: Sourcing Diode/Equivalent: MOSPEC U15A60 (anode on left)

How is the board marked? Is this the board?
Can you check if you have continuity between the tab and either the left or right pin?

[theflyingaj]

Re: Sourcing Diode/Equivalent: MOSPEC U15A60 (anode on left)

yes, that is my board, only my board has one large cap instead of two.

[theflyingaj]

Re: Sourcing Diode/Equivalent: MOSPEC U15A60 (anode on left)

on the new part, there is continuity between the left pin and the tab.

[theflyingaj]

Re: Sourcing Diode/Equivalent: MOSPEC U15A60 (anode on left)

both the old and new rectifiers have continuity between the left pin and the tab. using a diode tester, the old one tests open circuit between the pins in both directions. the new one tests 0.438v with the red lead on the right pin and black on the left pin.

this is the current condition of my board:
http://oi67.tinypic.com/igxj5v.jpg

(i had to make a modification to the diode rectifier bridge on the far left as it had a different mounting style.)

[R_J]

Re: Sourcing Diode/Equivalent: MOSPEC U15A60 (anode on left)

It just seems odd that they mark the board with A and K and put the diode with the (+) to the K and the (-) to the A

What about this FES16JTR. Every time I find a reverse configuration it's obsolete or it needs to come from China

[petehall347]

Re: Sourcing Diode/Equivalent: MOSPEC U15A60 (anode on left)

It just seems odd that they mark the board with A and K and put the diode with the (+) to the K and the (-) to the A

i remember it was always marked one way then someone decided to mark the other way .but this was a very long time ago .. i just trust my meter and the schematic .

[theflyingaj]

Re: Sourcing Diode/Equivalent: MOSPEC U15A60 (anode on left)

here is a picture of the back of the circuit board:
http://oi68.tinypic.com/28i5cns.jpg

it looks like the "A" is connected to "MTR1 RED" and "K" is connected to "MTR2 BLACK" which are the two power leads to the treadmill belt motor that is not working. which one should be the anode and which one should be the cathode?

is it standard for "K" to stand for cathode?

here are the two pieces next to the circuit board.

http://tinypic.com/r/24ay1wz/9

both pieces pictured test with connectivity between the tab and the left prong. is something mislabeled? that seems unlikely. i don't have much experience with these things, but is the old one labeled backwards? doesn't the electricity have to flow from "A" to "K" to "MTR1 RED" to the motor? that would mean the new one is correctly labeled, and the old one was mislabeled, or labeled with another convention.

[R_J]

Re: Sourcing Diode/Equivalent: MOSPEC U15A60 (anode on left)

Something seems confusing but if you look at a bridge rectifier, they mark the junction of the two diodes (K)cathodes as positive. so I wonder if the original diode (+) is the cathode, They marked it like they mark bridge diodes, so the new diode would work. Clear as mud.
Diodes across dc motors have the cathode to the positive lead.

[petehall347]

Re: Sourcing Diode/Equivalent: MOSPEC U15A60 (anode on left)

looks dead easy being as it shows A K on the board .. put your meter on diode test to see if diode matches the markings on the pcb

[budm]

Re: Sourcing Diode/Equivalent: MOSPEC U15A60 (anode on left)

The spec sheet shows the internal layout of the Diode, but it does not match the board silkscreen, need to trace out the circuit to find how this diode being used.
Looking a the traces based on your pictures, RJ's schematic looks to be correct, it looks like the diode is being used as snubber diode.
https://cdn.badcaps-static.com/pdfs/...28f7c07cc6.pdf

What is the P/N of U1 IC?

[theflyingaj]

Re: Sourcing Diode/Equivalent: MOSPEC U15A60 (anode on left)

ok, i admit i am a newbie to troubleshooting circuits. i did not realize that 'K' is the standard symbol for cathode as 'C' is reserved for the collector of a transistor. now at least that makes sense.

What is the P/N of U1 IC?

i'm not certain what you're asking, but i'm guessing you're asking for the part number of the underlying circuit board. that is included below:
JHT.CO.
2003.06.05
PCB230D003H

if you're asking for something else, let me know what it is and i'll post the information.