Help with Bentek DMC BP-200AD Power Supply

[grzesiek]

Re: Help with Bentek DMC BP-200AD Power Supply

Although I always warn people when they are about to take dangerous high voltage measurements, I do often forget to tell them to put on safety glasses. Sorry about that, I really hope you're okay.

No need to appologize. I always take basic safety precautions when working on most anything. You need not feel responsible for not stating the obvious.

we can trick the power supply to "think" that the standby section is okay - if you have spare chargers and adapters, that is).

Do you mean stuff like wall chargers and adapters for other devices? If so, Yes. If not could you be more spicific?

Any chance you know what C22 was rated for? It's not necessary, but would be interesting to know. Hopefully there are enough remains of that capacitor to determine that. If not, what are the part numbers on IC3?

Attached are pictures of the casing of the C22 Capacitor, as well as one of IC3. So no problem with Identification, but the part number of IC3 is 5M0365R.

I'll get on the next set of tests you described now.

[grzesiek]

Re: Help with Bentek DMC BP-200AD Power Supply

Attached are pictures of the casing of the C22 Capacitor, as well as one of IC3. So no problem with Identification, but the part number of IC3 is 5M0365R.

Forgot to post Pics

[grzesiek]

Re: Help with Bentek DMC BP-200AD Power Supply

OK. I removed all of the bellow...

D4, D5, D15, D16, Q5 ,Q6 ,R2 ,R3 ,R5, R6 ,R7 ,R8 ,R9 ,R22 ,RS1 ,RS2

All of the Diodes tested 'Not Good'

Only Resistors R5 and R55 Tested 'Good'

Here Are the values I coded the Resistors as and their Tested Values.

RS1 - .24 Ohm 5% - Open
RS2 - .24 Ohm 5% - Open
R2 - 23k Ohm 10% - Open
R3 - 23k Ohm 10% - Open
R5 - 22k Ohm 5% - 22k Ohm
R6 - 23 Ohm 5% - 12.3 Ohm
R7 - 28k Ohm 5% - 18.1 Ohm
R8 - 23M Ohm .1% - .786M Ohm
R9 - 23M Ohm .1% - .767M Ohm
R22 - 30 Ohm 5% - 10.2 Ohm
R55 - 4.7k Ohm 5% - 4.73K Ohm

I've Attached Photos of all the resistors (Pic name is Resistor). My eyes are not near what they used to be, so I had to use Pics to help identify them. If anyone disagrees with the values I used Please let me know.

Using the Diode test All the Diodes tested gave a result of 000.

[grzesiek]

Re: Help with Bentek DMC BP-200AD Power Supply

R8 - 23M Ohm .1% - .786M Ohm
R9 - 23M Ohm .1% - .767M Ohm

Correction R8 test value was .768M Ohm

Also, I think I mis-identified them. I'm thinking they are 760k Ohm 1%.

If this is correct, then they are very close to 'Good'.

[lti]

Re: Help with Bentek DMC BP-200AD Power Supply

I think R6 and R22 are good as well. Their color codes match the measured values.

[grzesiek]

Re: Help with Bentek DMC BP-200AD Power Supply

I think R6 and R22 are good as well. Their color codes match the measured values.

Reading R6 as Brown, Red, Black, Gold, I agree. I saw the first band as Red and the second as orange (old eyes).

Reading R22 as Brown, Black, Black, Gold, I agree. I saw the first band as orange (old Eyes).

Thanks for looking. After looking at the photos again, I agree, R6 and R22 are likely good.

[momaka]

Re: Help with Bentek DMC BP-200AD Power Supply

Do you mean stuff like wall chargers and adapters for other devices?

Yes.
But with the number of potentially bad parts, you need not worry about the chargers/adapters now.

Attached are pictures of the casing of the C22 Capacitor, as well as one of IC3. So no problem with Identification, but the part number of IC3 is 5M0365R.

C22... 22uF, 35V. Means the voltage must have went way over 35V for that thing to launch like it did. No wonder if this is why the APFC controller died. I'm actually very surprised that IC3 didn't blow first! It's rated for 30V max too (or maybe it has and that's why standby isn't working properly). No Zener diode protection either. I think tom66 is right to say that this is a badly designed power supply.

Using the Diode test All the Diodes tested gave a result of 000.

Is that both when the diodes are forward-biased and reverse-biased with the multimeter?
Just to rule out any foul measurements, can you check what readings you get for D19 and D20. If nothing else blew up besides that capacitor, D19 and D20 should be good. Out of circuit, you will get a reading in one direction (when forward-biased) and no reading in the other direction (reverse biased). If not, can you check the bridge rectifier, BD1? That one should be good for sure. Just put red probe on either of two the middle pins and black probe on the pin closest to the edge of the board. You should get a reading that is not "000". Probably anywhere between 300-800 mV or 0.300-0.800 V (may take a second or 2 for the measurement to get there).

Also, as far as the resistors go...
R2 and R3 are 910 KOhms (according to this calculator) so check it again. Not sure if that's right, though.
R6 is 12 Ohm, so the reading you got is good (as lti noted).
R7 is 18 KOhm, so the reading you got is good.
R8 and R9 are 750 KOhm, so the reading you got is good.
R22 is 10 Ohms, so the reading you got is good.

That leaves only RS1 and RS2 as bad, and potentially all of those diodes.

With all of these parts removed, also check the resistance between pin 6 (GND) and the rest of the pins on IC1, the FAN7527B APFC controller (page 3 on this data sheet shows the pinouts)
Of most particular interest are the readings across pins 4-6, 7-6, and 8-6. Let me know what values you get.

Since there are quite a few failed parts so far, at this point I would like to ask you - how much time and money are you willing to spend on this power supply? Money on parts likely won't be very much at all, but the time to fix it may be quite high. I just want to get a feeling if you would like to continue troubleshooting this power supply since it will get more involved or if you instead would like to get a similar power supply that may be compatible. I'm okay with either options and don't mind guiding you whichever you pick.

[grzesiek]

Re: Help with Bentek DMC BP-200AD Power Supply

Also, as far as the resistors go...
R2 and R3 are 910 KOhms (according to this calculator) so check it again. Not sure if that's right, though.
R6 is 12 Ohm, so the reading you got is good (as lti noted).
R7 is 18 KOhm, so the reading you got is good.
R8 and R9 are 750 KOhm, so the reading you got is good.
R22 is 10 Ohms, so the reading you got is good.

That leaves only RS1 and RS2 as bad, and potentially all of those diodes.

Glad I posted those pics. I really struggled with the colors of the bands.

By the way... the back (flat) side of Diode Q6 is blowen out as well

Is that both when the diodes are forward-biased and reverse-biased with the multimeter?
Just to rule out any foul measurements, can you check what readings you get for D19 and D20.

Yes that was both forward-biased and reverse-biased.

D19 (in board) - 589 Forward, No reading reverse
D20 (in board) - 589 Forward, No reading reverse
BD1 (in board) - 493 and 508 (depending on pin) forward, no reading reverse

You should get a reading that is not "000".

For my meter '1' is no reading (probes not touching anything) All of the other diodes gave a reading of '1' (no reading).

With all of these parts removed, also check the resistance between pin 6 (GND) and the rest of the pins on IC1, the FAN7527B APFC controller (page 3 on this data sheet shows the pinouts)
Of most particular interest are the readings across pins 4-6, 7-6, and 8-6. Let me know what values you get.

Meter set at 2000 Ohm
Pin 6 - 1 - 1881 Ohm
Pin 6 - 2 - 1927 Ohm
Pin 6 - 3 - 1909 Ohm
Pin 6 - 4 - 1969 Ohm
Pin 6 - 5 - 1874 Ohm
Pin 6 - 7 - 27 Ohm
Pin 6 - 8 - 28 Ohm

Here's where I show my ignorance... When I set the meter at at 20k Ohm I got the following readings...
Pin 6 - 1 - 6.63K Ohm
Pin 6 - 2 - 7.28 Ohm
Pin 6 - 3 - 7.03 Ohm
Pin 6 - 4 - 7.45 Ohm
Pin 6 - 5 - 7.05 Ohm
Pin 6 - 7 - .03k Ohm
Pin 6 - 8 - .03k Ohm

I would have thought that by increasing the range by 10x that the second readings from 6-1 thru 6-5 would have looked more like the second reading from pin 6-7 and 6-8. What don't I know about reading resistance ?

Since there are quite a few failed parts so far, at this point I would like to ask you - how much time and money are you willing to spend on this power supply? Money on parts likely won't be very much at all, but the time to fix it may be quite high. I just want to get a feeling if you would like to continue troubleshooting this power supply since it will get more involved or if you instead would like to get a similar power supply that may be compatible. I'm okay with either options and don't mind guiding you whichever you pick.

I can't express enough how much I appreciate your time on this.

To answer your question... I have looked into replacing this power supply, with no luck. And even if I could find an exact replacement, I'm not sure I would want it (as we all know how poor a quality board this is). I would be interested in a good quality replacement with the same specs (but I have not been able to locate one). If I could locate a good quality board then that would be my preferance over spending the time on this one. However, If I'm going to replace this with something that will fail again and again, then I'd rather fix this, and learn how to keep this thing going.

I will continue to search for a replacement board, but in the mean time (as long as you are still willing to spend the time) I'd like to continue repairing this board.

[grzesiek]

Re: Help with Bentek DMC BP-200AD Power Supply

For my meter '1' is no reading (probes not touching anything) All of the other diodes gave a reading of '1' (no reading).

I restested Doides D4, D5, D15, D16 and the readings are '000' not '1'

[momaka]

Re: Help with Bentek DMC BP-200AD Power Supply

D19 (in board) - 589 Forward, No reading reverse
D20 (in board) - 589 Forward, No reading reverse
BD1 (in board) - 493 and 508 (depending on pin) forward, no reading reverse

I restested Doides D4, D5, D15, D16 and the readings are '000' not '1'

So no foul reading then (unfortunately). That means D4, D5, D15, and D16 are shorted and will need to be replaced.

Meter set at 2000 Ohm
Pin 6 - 1 - 1881 Ohm
Pin 6 - 2 - 1927 Ohm
Pin 6 - 3 - 1909 Ohm
Pin 6 - 4 - 1969 Ohm
Pin 6 - 5 - 1874 Ohm
Pin 6 - 7 - 27 Ohm
Pin 6 - 8 - 28 Ohm

The output (pin 7) and voltage supply pin (pin 8) are pretty much shorted to ground. Your FAN7527B IC is toast .

That means Q1 is also likely toast. Check for short circuit (200 Ohm scale) between its 3 pins and let me know what you find. D3 probably survived, but check it anyways.

So the failed parts we have so far are:
RS1/RS2, D4, D5, D15, D16, Q6, IC3, and C22.
I checked the prices on Mouser, and replacements for RS1/RS2 run for ~$0.50 each. The FAN7527B IC is just a bit under $1 and it is in stock (which is good because sometimes these ICs can be phased out and then finding a replacement becomes a real hassle). C22 will be no more than $0.10-0.30. I don't know the part numbers for D4, D5, D15, D16, and Q6 but I'm guessing they would all be around $2-4 total. Q1 (if it's bad), $1-3. Shipping from Mouser usually runs me around $6 to get it here to VA/D.C. Because of that, I usually buy spares for the parts I am replacing, just in case I run into an "oopsie" moment.

We will probably need to check more parts, but it's getting late so I'll continue on this tomorrow afternoon.

Here's where I show my ignorance... When I set the meter at at 20k Ohm I got the following readings...
Pin 6 - 1 - 6.63K Ohm
Pin 6 - 2 - 7.28 Ohm
Pin 6 - 3 - 7.03 Ohm
Pin 6 - 4 - 7.45 Ohm
Pin 6 - 5 - 7.05 Ohm
Pin 6 - 7 - .03k Ohm
Pin 6 - 8 - .03k Ohm

I would have thought that by increasing the range by 10x that the second readings from 6-1 thru 6-5 would have looked more like the second reading from pin 6-7 and 6-8. What don't I know about reading resistance ?

Nothing. Your multimeter is probably a 830B variant, and most of those can bias diodes on the 2000 Ohm scale, hence you get lower resistances if there are diodes/transistors in the circuit (which there are in that FAN7527B IC). I often use the 2000 Ohm scale on my 830D to check diodes and transistors. Readings are usually close to what the diode test function shows.
When checking for short-circuit, though, I always pick the lowest scale (200 Ohms on most manual multimeters) and don't bother measuring with the others.

I will continue to search for a replacement board, but in the mean time (as long as you are still willing to spend the time) I'd like to continue repairing this board.

Sounds good. I do like exercising my mind with these circuits so I don't mind.
I actually did some checking for myself yesterday just because I have a similar TV board here that was also quite horrible to fix (though nowhere near as bad as yours)...
There are 24V 10A power supplies for about $20-25 on ebay. One of these combined with a computer power supply and some hacking or with 2 DC-DC converter circuits to get 12V and 5V, and you have a quick, somewhat cheap, but dirty solution. Also, I don't know how much those cheap Chinese power supplies on ebay can be trusted.

[grzesiek]

Re: Help with Bentek DMC BP-200AD Power Supply

The output (pin 7) and voltage supply pin (pin 8) are pretty much shorted to ground. Your FAN7527B IC is toast .

That means Q1 is also likely toast. Check for short circuit (200 Ohm scale) between its 3 pins and let me know what you find. D3 probably survived, but check it anyways.

Readings from Q1 on 200ohm scale
Pins 1-2 - .5
Pins 1-3 - .4
Pins 2-3 - .4

Reading from D3 Diode test mode
380

So the failed parts we have so far are:
RS1/RS2, D4, D5, D15, D16, Q6, IC3, and C22.
I checked the prices on Mouser...

I started putting together a shopping cart on Mouser, and stopped. I notice there are several different FAN7527B IC's, and Resistors (RS1 RS2) have a number of Watt values. I don't think the FAN7527B matters(?) but I'm thinking it will matter for the other components. You are doing so much already, I hate to ask, but I'll need help putting together a parts list.

Also, I can see the numbers on D15 (526 5819) and D16 (514 5819), But D4 and D5 I can't even tell if there are numbers on them. And I don't have a powerfull enough magnifing glass to see them. I'm not sure how to Identify them. Any ideas?

[tom66]

Re: Help with Bentek DMC BP-200AD Power Supply

Q1's dead.

[momaka]

Re: Help with Bentek DMC BP-200AD Power Supply

Yup, Q3 is toast. Will need the numbers off of that too. D3 is good, though.

I started putting together a shopping cart on Mouser, and stopped. I notice there are several different FAN7527B IC's, and Resistors (RS1 RS2) have a number of Watt values. I don't think the FAN7527B matters(?)

It does, actually. I see 2 different packages for the FAN7527B IC - one is SMT/SMD and the other is regular through-hole/DIP. You want the DIP, and not the SMT/SMD. Both of these will do (the first one is just end of life and low on stock so that's why it's a bit cheaper):
http://www.mouser.com/ProductDetail/...kHW4cmTeaJI%3d
http://www.mouser.com/ProductDetail/...BFnJwUYtbiE%3d


As for resistors RS1 and RS2, I found these 4:
http://www.mouser.com/ProductDetail/...52b2miruAm4%3d
http://www.mouser.com/ProductDetail/...H9J8s5B1ptI%3d
http://www.mouser.com/ProductDetail/...3EBaDv2%2fs%3d
http://www.mouser.com/ProductDetail/...IqVLAWocRsk%3d
I'm not sure which one is suitable or the best choice, though (I do remember reading that certain types of resistors are not recommended for high-voltage applications). Judging by the size, RS1 and RS2 seem to be rated for 2 or 3W. The one in the first link above is 5W so that will have us covered. I just hope someone knows if wirewound resistors would be okay in this application.

D15 and D16 came up as 1n5819 - 40V, 1A schottky barrier diodes.
http://www.mouser.com/ProductDetail/...MPqz0jMjzlk%3d
I think the same diodes (1n5819) would also be okay for D4 and D5 - after all, they are attached to the output of the FAN7527B IC, which according to the data sheet cannot exceed the supply voltage, which cannot exceed 30V.
But having 1 or 2 of these in case the above don't work wouldn't hurt either:
http://www.mouser.com/ProductDetail/...T%2fwJTX3lg%3d

That leaves R10.... *perhaps* a 10 to 100 Ohm 1/2W resistor will work.
That pretty much completes the PFC section of the power supply and leaves us with the standby section...

C52 should be replaced just because it looks like it took a lot of heat. D7, D8, and D9 need to be checked, especially D7 and D9 since those rectify the current that supplies IC1 and IC3. R22 and R25 should be good, but check them too. Likewise with R23, D17, Q4, Q5, R16, and R18.

Also, any luck identifying the numbers on Q6?

[grzesiek]

Re: Help with Bentek DMC BP-200AD Power Supply

Also, any luck identifying the numbers on Q6?

I've attached a Pic of Q6.

So Far R22 R23 and R25 tested Good.

I've yet to test R16 and R18. D7 D8 D9 D17 Q4 and Q5. I want to take them out of the board. I'll get on that tomorrow.

[tom66]

Re: Help with Bentek DMC BP-200AD Power Supply

Possibly a 2N2907.

[grzesiek]

Re: Help with Bentek DMC BP-200AD Power Supply

So Here's My results...

D17 - 595
R16 Pic Attached - 998 (not good I think)
R18 Pic Attached - 989 (Not good I think)
R25 - 75 Ohm - Good
R22 - 10.2 Ohm - Good
R23 - 100.9 Ohm - Good

D7 - 486
D8 - 482
D9 - 483

I don't know how to test Q4 and Q5.

[momaka]

Re: Help with Bentek DMC BP-200AD Power Supply

R18 is 1 KOhm resistor, so the value you got indicates it is good.
R16 looks a bit toasty to tell precisely what its color code is. However, it looks like 1 KOhm as well. So it's probably fine too.

I don't know how to test Q4 and Q5.

Post what part numbers they have or post pictures.

I'll try look into the FAN7527B and 5M0365R data sheets on Sunday to see if we can make some modifications to the circuit so that the auxiliary voltage doesn't destroy them. It might be as simple as adding a few Zener diodes to the cart.

**EDIT**
R23 color code looks like a 100 KOhm resistor to me, not 100 Ohm. Did you measure it in or out of circuit?

[grzesiek]

Re: Help with Bentek DMC BP-200AD Power Supply

R18 is 1 KOhm resistor, so the value you got indicates it is good.
R16 looks a bit toasty to tell precisely what its color code is. However, it looks like 1 KOhm as well. So it's probably fine too.

You're right about R18... Head math I was thinking value was off by 10%, I see now only 1%

I coded R16 at 2Kohm (Not good), and I agree it's toasty, I think for the price it's worh replacing.

R23 color code looks like a 100 KOhm resistor to me, not 100 Ohm. Did you measure it in or out of circuit?

Your right R23 is a 100K ohm, and I typed result incorrectly, it measures 100.9K Ohm (in circuit).

Any hints on how to test Q4 and Q5.

***EDIT*** Just noticed request for part#'s/Pics of Q4 and Q5... Info to follow.

Do you need more information on D7, D8, and D9 results?

[grzesiek]

Re: Help with Bentek DMC BP-200AD Power Supply

Post what part numbers they have or post pictures.

Pics Of Q4 and Q5 attached

Numbers As I see them...

Q4 - KSP 2222A - F32
Q5 - KSP 2907A - 326

***EDIT***
I just noticed... 8 of the 11 digits of Q5 match what remains of Q6. Is it possible (likely) thay are the same part?

Q6 - ?SP ??07A - 326

[momaka]

Re: Help with Bentek DMC BP-200AD Power Supply

***EDIT***
I just noticed... 8 of the 11 digits of Q5 match what remains of Q6. Is it possible (likely) thay are the same part?

Excellent observation there. Yes, they almost certainly are.

As far as testing...
Q4: set transistor so that its flat side is facing you (just like in the picture). The left-most pin is pin 1, middle is pin 2, and right is pin 3. With the red (+) multimeter probe on the middle pin (pin 2) and multimeter set to diode test, you should get a diode reading when you touch either pin 1 or pin 3 with the black (-) multimeter probe. Also you should not get any short circuit/beeping from the multimeter between any of the pins (out of circuit, of course). If you do, then the transistor is bad.

Q5: same procedure as Q4 but switch your multimeter probes (i.e. black probe goes on pin 2 and red probe goes on either pin 1 or pin 3).

Also, in case you want to test any other transistors, this is the general procedure:
1) find transistor data sheet to see if it's PNP or NPN
2) next find the pinout of the transistor - more specifically which pin is Base
3) For NPN, multimeter red (+) probe goes on this pin and you test the transistor by checking if you get a diode reading when you put the black (-) probe on either of the other two pins (the Emitter and Collector). For PNP transistors, it's just reverse of that for NPN.
4) Out of circuit, any short-circuit or low-ohm readings between B-E, C-E, and B-C pins means transistor is bad.

By the way, sorry to say, but I haven't looked at the FAN7527B and 5M0365R data sheets yet. I'll try to do that by the end of the week.