DAC-19M009 dead?

[eric2084]

Re: DAC-19M009 dead?

Found the MBRF20200CTG, it looks like it is a direct replacement for SB20200FCT as it has an isolated case too. It's available at Digi-Key.

[papagoose]

Re: DAC-19M009 dead?

Haha I meant it like a contraction of '(the) stuff of legends'

[PlainBill]

Re: DAC-19M009 dead?

Well everyone, the diode arrived, I fitted it with the insulation kit, and everything seems to work fine! Been using the monitor for a couple of hours now Hopefully all the components were correct and nothing else gets damaged

Thank you to everyone who helped out, especially retiredcaps for the exhaustive initial tests to narrow down the fault, and to PlainBill for somehow incredibly tracking it down to that one diode! You guys are legends

Glad it's working.

PLEASE!!! A Legend is a figure from the past. As retiredcaps will confirm, we are very much alive and darn well want to keep it that way!!!

PlainBill

[papagoose]

Re: DAC-19M009 dead?

Well everyone, the diode arrived, I fitted it with the insulation kit, and everything seems to work fine! Been using the monitor for a couple of hours now Hopefully all the components were correct and nothing else gets damaged

Thank you to everyone who helped out, especially retiredcaps for the exhaustive initial tests to narrow down the fault, and to PlainBill for somehow incredibly tracking it down to that one diode! You guys are legends

[papagoose]

Re: DAC-19M009 dead?

Thanks UniT3d, I've put in an order for the diode and for the insulation kit, hopefully it'll arrive this week so shall see soon if it works! (4-5 days shipping time unfortunately)

[UniT3d]

Re: DAC-19M009 dead?

Whoops, my bad, missed that the packaging needs to be TO-220AB-FP for full plastic packaging. If full plastic packaging configuration is not available, insulation kits such as this should be fine:

http://au.element14.com/multicomp/mk...-220/dp/520214

I couldn't find full plastic packaging at the rated 20A 200V schottkys either at element14 or rs-components.

[PlainBill]

Re: DAC-19M009 dead?

Pardon me for cutting in, I believe this would be another suitable drop-in replacement:

http://au.element14.com/multicomp/mb...0ab/dp/1857516

This meets the original voltage and current ratings, but as far as I can see, the tab is not isolated. This application requires either a device with an insulated tab or an insulation kit must be used.

PlainBill

[PlainBill]

Re: DAC-19M009 dead?

Would this be OK?

http://au.element14.com/taiwan-semic...50v/dp/1453402

It has the same max voltage rating as the existing one, and the other parameters seem similar as well

Sorry, not suitable. In the clear light of day I realized the original part was rated for 200 volts. Also, the output os the supply seems to be 24V, not 12V. I'm really not comfortable recommending a diode array which is rated for less than 200 volts. ALSO, the original had an insulated tab, this one doesn't.

PlainBill

[UniT3d]

Re: DAC-19M009 dead?

Pardon me for cutting in, I believe this would be another suitable drop-in replacement:

http://au.element14.com/multicomp/mb...0ab/dp/1857516

[papagoose]

Re: DAC-19M009 dead?

Would this be OK?

http://au.element14.com/taiwan-semic...50v/dp/1453402

It has the same max voltage rating as the existing one, and the other parameters seem similar as well

[PlainBill]

Re: DAC-19M009 dead?

This looks like it may do the trick. VF40100C-E3/4W It's only rated for 100 volts reverse, but I will allow older, wiser heads to verify that.

PlainBill

[retiredcaps]

Re: DAC-19M009 dead?

SB20200FCT

Datasheet is here

http://pdf1.alldatasheet.com/datashe...B20200FCT.html

findchips.com or ebay cannot find this part so it looks like you will need an equivalent.

Searching for "20A DUAL SCHOTTKY BARRIER RECTIFIER" in digikey shows 5 results.

Unfortunately, I don't know enough about which parameters are critical to the proper operation.

I will have to defer again to PlainBill or others to fill in. I feel like a pitcher who can go 7 innings, but need the bullpen and closer to finish the game! (Since PlainBill was just watching the baseball game).

[papagoose]

Re: DAC-19M009 dead?

What is the part number on that diode?

It says on it

PEC 634
SB20200FCT

[retiredcaps]

Re: DAC-19M009 dead?

What is the part number on that diode?

[papagoose]

Re: DAC-19M009 dead?

If it looks like this

http://en.wikipedia.org/wiki/File:Schottky.jpg

then the 0 reading suggests it is a bad component.

Yep it looks like those, same symbol drawn on them. So it sounds like we know what to replace next...?

[retiredcaps]

Re: DAC-19M009 dead?

Am I correct in thinking this diode is actually 2 diodes put together? If I understand the drawing on the front correctly, they are connected in opposite directions. One of them reads 350 one way and off scale the other. The other reads 0 in both directions

If it looks like this

http://en.wikipedia.org/wiki/File:Schottky.jpg

then the 0 reading suggests it is a bad component.

[papagoose]

Re: DAC-19M009 dead?

Charming. Refer to the attached picture. If you would, remove the diode circled in red. Then measure the resistance between the two points circled in black. Also test the diode by setting the meter in diode test range and checking from the center lead to each side lead. Then reverse the DMM leads and test again.

PlainBill

OK now I am excited! With the diode out, the resistance between the two circled points is off scale (they don't seem to be connected).

Am I correct in thinking this diode is actually 2 diodes put together? If I understand the drawing on the front correctly, they are connected in opposite directions. One of them reads 350 one way and off scale the other. The other reads 0 in both directions

[papagoose]

Re: DAC-19M009 dead?

Haha it would have to be one of the diodes that is screwed into one of the metal dividers on the other side of the board! Just waiting for the soldering iron to heat up now...

[PlainBill]

Re: DAC-19M009 dead?

The resistance is < 1 ohm


The diode test read 0


And this read 0 as well!

Charming. Refer to the attached picture. If you would, remove the diode circled in red. Then measure the resistance between the two points circled in black. Also test the diode by setting the meter in diode test range and checking from the center lead to each side lead. Then reverse the DMM leads and test again.

PlainBill

[papagoose]

Re: DAC-19M009 dead?

Test 1. Power disconnected. DMM on the 200 ohm scale. Black lead on the black circle. Measure the resistance to the lead between 8 and 9 on the latest picture. This should read open.

The resistance is < 1 ohm

Test 2. Now switch to the diode check scale and measure with the leads on the same points. What is the reading?

The diode test read 0

Test 3. Reverse the leads - Red to the black circle, black to the point between 8 and 9. What is the reading?

And this read 0 as well!