Chimei DAC-19M009 Power Supply problems

[mcb1]

Re: Chimei DAC-19M009 Power Supply problems

PlainBill

Good thoughts.
I wasn't intending to make a career of it, but it is something that would suit an age group that prefers repair to replace.

I haven't been actively looking for monitors, so I'm not sure what the supply is like.
It is certainly something that my son could undertake to pay his way, and I might suggestion it to him.

Thanks for the help so far.
Mark

[PlainBill]

Re: Chimei DAC-19M009 Power Supply problems

PlainBill
Thanks for that

I was able to download the datasheet, and what an amazing device.
It won't be until next week that I have an opportunity to look at the monitor again, but hopefully it should be more obvious with the circuit.

I've been in the electronics game for 30 odd years, but for the last 10 or so, I haven't really used a soldering iron in anger.
Monitors are something I haven't really been involved with, so its a bit refreshing.

Great site and great advice...please keep it up.
There is far too much being thrown away, that deserves a new life.


Mark

In many ways LCD monitors are ideal for the older people who wish to re-enter electronics repair (provided they remember which end of the soldering iron to grasp). There is an adequate supply of repairable monitors, they are fairly light weight so there is less chance of back strain, most common components are readily available at reasonable prices, and there is a sufficient knowledge base that at least the rudiments of the operation can be discerned easily.

PlainBill

[mcb1]

Re: Chimei DAC-19M009 Power Supply problems

PlainBill
Thanks for that

I was able to download the datasheet, and what an amazing device.
It won't be until next week that I have an opportunity to look at the monitor again, but hopefully it should be more obvious with the circuit.

I've been in the electronics game for 30 odd years, but for the last 10 or so, I haven't really used a soldering iron in anger.
Monitors are something I haven't really been involved with, so its a bit refreshing.

Great site and great advice...please keep it up.
There is far too much being thrown away, that deserves a new life.


Mark

[PlainBill]

Re: Chimei DAC-19M009 Power Supply problems

jetadm123
The picture is the same as in #15 (minus the bulging cap)
I forgot to include that the fuses were all intact, but thanks for the suggestions.


PlainBill
I managed to track down the cicuit diagram thanks to some other posts.
http://ftpkuban.com/FTP/Manual/ViewSonic/


My initial thoughts about where the inverter driver fitted in was wrong, so I'll do some more digging, and check the zener voltage.


Thanks
very much

Mark

The LC7575 is a 'green ' SMPS controller. The keys are pins 8, 6, and the 22uF, 50Volt cap. Pin 8 is supposed to dram 1Ma of current through the 10 K resistor until the SMPS starts up. The IC uses that current to charge the cap up to the start-up voltage. It uses that stored charge to run until the T801 starts to provide run current through D807. I've seen a lot of failures on the 'green' SMPS controllers.

PlainBill

[mcb1]

Re: Chimei DAC-19M009 Power Supply problems

jetadm123
The picture is the same as in #15 (minus the bulging cap)
I forgot to include that the fuses were all intact, but thanks for the suggestions.


PlainBill
I managed to track down the cicuit diagram thanks to some other posts.
http://ftpkuban.com/FTP/Manual/ViewSonic/


My initial thoughts about where the inverter driver fitted in was wrong, so I'll do some more digging, and check the zener voltage.


Thanks
very much

Mark

[PlainBill]

Re: Chimei DAC-19M009 Power Supply problems

Firstly, what a great site.
I have managed to rescue one Viewsonic from landfill, with the help of this site, and now have a second that I'm hoping someone can help with.

I have a VX2235WM that has a DAC 19M009 supply as pictured in some of the earlier posts.
I have taken the opportunity to replace all the caps, (although none were showing any signs of distress), and gone over any suspect solder joints.

I can measure 320vDC across the capacitor (yes NZ is 230VAC), but there is nothing on the connectors, or any of the components on the low voltage side of the inverter.

The switching FET that drives the transformer seemed okay, but to be sure I replaced this, and still nothing.

Looking underneath all the components around the inverter IC, seem to be at least what they should be, and there seems to be nothing that the smoke has escaped from.

I was hoping that someone might have a circuit (or some other ideas to chase), as I'm determined to not let it beat me.

Cheers
Mark

Since you are willing to try this on your own, I suggest looking up the datasheet for the SMPS controller. It is an 8 pin IC, usually on the bottom side of the board close to the transformer. Looking at the voltages on the IC and comparing them with the datasheet will help determine if the SMPS is getting appropriate voltages.

PlainBill

[jetadm123]

Re: Chimei DAC-19M009 Power Supply problems

Hello! I suggest that you post pictures (top and bottom) of your power supply/inverter board per the the suggested forum guidelines:

https://www.badcaps.net/forum/showthread.php?t=1868


At least this way, some of the more experienced folks (like PlainBill) can mark off some points for you to test. If anything, seeing a photo might jar someone's memory into suggesting specific components to test. Also, it would help to tell us if you hear any sounds or see, say, a quick flash of the power led, etc.

Without the above info, I would at least try checking for fuses underneath the power board. They would be surface mount and would be labeled FXXX (where XXX is a 3-digit number). Good luck!

[mcb1]

Re: Chimei DAC-19M009 Power Supply problems

Firstly, what a great site.
I have managed to rescue one Viewsonic from landfill, with the help of this site, and now have a second that I'm hoping someone can help with.

I have a VX2235WM that has a DAC 19M009 supply as pictured in some of the earlier posts.
I have taken the opportunity to replace all the caps, (although none were showing any signs of distress), and gone over any suspect solder joints.

I can measure 320vDC across the capacitor (yes NZ is 230VAC), but there is nothing on the connectors, or any of the components on the low voltage side of the inverter.

The switching FET that drives the transformer seemed okay, but to be sure I replaced this, and still nothing.

Looking underneath all the components around the inverter IC, seem to be at least what they should be, and there seems to be nothing that the smoke has escaped from.

I was hoping that someone might have a circuit (or some other ideas to chase), as I'm determined to not let it beat me.

Cheers
Mark

[PlainBill]

Re: Chimei DAC-19M009 Power Supply problems

Had both my eyes done a few years ago. Most amazing thing to me after the op wasn't the improved vision but the COLORs. I'd gotten so used to seeing a washed out hazy version of the world, seeing bright vivid colors was an unexpected thrill!

I had the same reaction!!! A few hours after the surgery we took the shield off to put in eye drops. Suddenly colors were more vivid with my left eye.

I have a clear plastic computer case on my desk. The fans have UV LEDS in them. With my right eye I can barely see them; with the left eye they are quite bright. I understand a rainbow will even have an extra band (if we ever get rain here).

PlainBill

[plugh]

Re: Chimei DAC-19M009 Power Supply problems

Replaced the three 220uF's with the Nichicon's, reassembled, powered up - Works again!

Many thanks; this forum is a great resource!

The usual recommendation is to order from a reputable distributor.

Go to their site, click on About Us. MCM is one of the member companies in a large multi-national corporation.

No I don't work for them. I simply prefer to deal with a local Brick & Mortar (rare is this market). Having said that, I WAS quite disappointed when I went there this time (been a couple years since last visit). They have closed their show-room and are now purely a warehousing / distribution operation.

Last time around, I went in the show room and talked with the sales reps. They would pull parts from the warehouse while you were there, you could inspect them, check alternatives, actually "shop"... Now it is ONLY web or phone orders, with a three hour turnaround for will-call orders. Still nice having them up the road, but they've lost some of their appeal to me. Oh well...

(I've bought from Digi-key before, but the finger twiddling shipping wait drives me nuts when I'm in the middle of something.)

First eye checks out 20/20! Surgery on other eye Jun 23rd.

Had both my eyes done a few years ago. Most amazing thing to me after the op wasn't the improved vision but the COLORs. I'd gotten so used to seeing a washed out hazy version of the world, seeing bright vivid colors was an unexpected thrill!

[PlainBill]

Re: Chimei DAC-19M009 Power Supply problems

Another Chimei DAC-19M009 here...

not mine, a friends; he said display went black.

Told him to try switching dvi vs vga; no change.
Told him to use flashlight; can see ghost image.
Told him to adjust bright/contrast;
... with control turned down display sometimes lights on powerup up.

He opened unit up, pulled PS board, brought it over.
(It is the same board and rev as in preceding post)
Inspection reveals board discoloration around P605 inverter ICs,
and 3 * CapXon 220uF 25V 105C 'KF' caps with bowed tops.
(one by glass fuse, one between horiz cap and vert resistor,
one between large green cap and regulator in above pic)

Diode checked the P605's - they seem OK.
(thanks for the datasheet pointer above)

Another thread here gave pointer to CapXon
http://www.capxongroup.com/en/prod_all_cat_full.aspx
The 'KF' datasheet says 220uF 25V is low impedance, 8x11.5

A local warehouse outlet (MCM Electronics) listed two 220uF 25V radial caps
31-7090 - Capacitor 25V 220uf 105c HI Temp,radial (8D X 11.5l MM) $1.09
31-5550 - Capacitor 25V 220uf Low ESR Hitemp, Hifreq. Rad. 8dx15l MM $1.89
unfortunately the 5550's were on backorder (21 days out), but 35V wasn't
31-5685 - Capacitor 35V 220uf Low ESR Hitemp, Hifreq. Rad. 8dx20l MM $2.19
(these are a LOT taller than the CapXon's but will still fit ok)

web-ordered and picked-up 3* 7090 and 3* 5685

Upon inspection, 5685's are Nichicon 'PL' series.

Markings on 7090's are 220uF 25V 105C GE with 76P4 stamped on side and
'M in a box' symbol (M looks more like a capital Sigma rotated 90 degrees)

Anyone know who / what this cap is? Specs / datasheet?

Or should I just go with the Nichicons? Note spec diffs:
CapXon KF 25V
---ripple 550mA rms at 105C 100KHz
---impedance 0.15 ohm at 20C 100KHz
Nichicon PL 35V
---ripple 795mA rms at 105C 10KHz~200KHz
---impedance 0.085 ohm at 20C 100KHz

Thanks!

The usual recommendation is to order from a reputable distributor.

For example, Digikey sells Panasonic FM 220uF 25Volt low ESR caps P12383-ND EEU-FM1E221 for $.33 each. Shipping will cost about $2.00. The monetary savings are marginal for three caps, but Capxon are commonly referred to a 'Crapxon' for their high failure rate. Those with experience usually replace ALL of them they find. Typically, this will run under $10 (including shipping) from Digikey, and you don't have to spend time trying to figure out what you actually received. (For best delivery time, specify USPS First Class Mail. Parts ordered today will be delivered Friday.)

PlainBill

[plugh]

Re: Chimei DAC-19M009 Power Supply problems

Can't find any 'GE series' on Panasonic site.

Did find a discontinued 'NHE' series that has a GE 'series code' in the part number.
Also, a search on '76P4' yields a pdf about transition from NHE to NHG series.

Guess I'll give the Nichicon a try...

[lucky13]

Re: Chimei DAC-19M009 Power Supply problems

Wow, Malware on that imageshack site posted by gothedler?

Ctrl-F4 killed it....

[plugh]

Re: Chimei DAC-19M009 Power Supply problems

from this page
How to Identify Japanese Electrolytic Capacitors
it appears 'M in a box' symbol is for Panasonic (Matsushita)

Now to see if I can track down specs on the 'GE' series...

[plugh]

Re: Chimei DAC-19M009 Power Supply problems

Another Chimei DAC-19M009 here...

not mine, a friends; he said display went black.

Told him to try switching dvi vs vga; no change.
Told him to use flashlight; can see ghost image.
Told him to adjust bright/contrast;
... with control turned down display sometimes lights on powerup up.

He opened unit up, pulled PS board, brought it over.
(It is the same board and rev as in preceding post)
Inspection reveals board discoloration around P605 inverter ICs,
and 3 * CapXon 220uF 25V 105C 'KF' caps with bowed tops.
(one by glass fuse, one between horiz cap and vert resistor,
one between large green cap and regulator in above pic)

Diode checked the P605's - they seem OK.
(thanks for the datasheet pointer above)

Another thread here gave pointer to CapXon
http://www.capxongroup.com/en/prod_all_cat_full.aspx
The 'KF' datasheet says 220uF 25V is low impedance, 8x11.5

A local warehouse outlet (MCM Electronics) listed two 220uF 25V radial caps
31-7090 - Capacitor 25V 220uf 105c HI Temp,radial (8D X 11.5l MM) $1.09
31-5550 - Capacitor 25V 220uf Low ESR Hitemp, Hifreq. Rad. 8dx15l MM $1.89
unfortunately the 5550's were on backorder (21 days out), but 35V wasn't
31-5685 - Capacitor 35V 220uf Low ESR Hitemp, Hifreq. Rad. 8dx20l MM $2.19
(these are a LOT taller than the CapXon's but will still fit ok)

web-ordered and picked-up 3* 7090 and 3* 5685

Upon inspection, 5685's are Nichicon 'PL' series.

Markings on 7090's are 220uF 25V 105C GE with 76P4 stamped on side and
'M in a box' symbol (M looks more like a capital Sigma rotated 90 degrees)

Anyone know who / what this cap is? Specs / datasheet?

Or should I just go with the Nichicons? Note spec diffs:
CapXon KF 25V
---ripple 550mA rms at 105C 100KHz
---impedance 0.15 ohm at 20C 100KHz
Nichicon PL 35V
---ripple 795mA rms at 105C 10KHz~200KHz
---impedance 0.085 ohm at 20C 100KHz

Thanks!

[gothelder]

Re: Chimei DAC-19M009 Power Supply problems

First problem: Read this.

Next, you have at least 5 bad caps.

PlainBill

Greetings again.

I figured that the canisters sitting upright should not have the tops be bowed out like that. The last time I was in the guts of a piece of equipment was in the 80's. (I really really like this monitor though). Hopefully it does not turn out its only botulism

I was hoping it was only a fuse but that was not to be, that I can replace in most circumstances, but when it comes to heavy duty soldering I know just enough to be dangerous.

Apologies for using offsite hosting but the images were too big for the badcaps.net hosting.

I will shrink them a bit and repost them in this reply so that they are hosted onsite. I expect they no longer need to be as DPI intensive as your likely to have already cracked it as it were.

Thanks for your response.

[PlainBill]

Re: Chimei DAC-19M009 Power Supply problems

Greetings

I have the same flavor of board with the same component configuration as far as I can tell.

I was able to test the fuse for continuity and there is no resistance so its not blown. (This is the one circled in blue)

I measured the VDC across the capacitor right near the power plug and got 172. I tested the other capacitor as long as I was in the guts of the beast at it read 17.

The fuse the other poster mentioned on mine appears to be fine. I was able to test the continuity across it on the back of the board and had 0 resistance.


and

First problem: Read this.

Next, you have at least 5 bad caps.

PlainBill

[gothelder]

Re: Chimei DAC-19M009 Power Supply problems

First of all,with the power supply plugged in (to both the monitor and AC power) CAREFULLY measure the voltage across the two pins of the large cap. I've circled them in red in the attached picture. This point packs enough of a punch to give you a jolt.

If you get either 150-170 VDC or 300-340 VDC the next step is to disconnect AC power from the board and unsolder 1 lead of the fuse circled in blue. Hook the board up again and see if the power LED works properly now.

If you still get nothing, it is time to take a picture of the area I have circled in green. Photograph both sides of the board. I am looking for any information on what voltages to expect.

PlainBill

Greetings

I have the same flavor of board with the same component configuration as far as I can tell.

I was able to test the fuse for continuity and there is no resistance so its not blown. (This is the one circled in blue)

I measured the VDC across the capacitor right near the power plug and got 172. I tested the other capacitor as long as I was in the guts of the beast at it read 17.

The fuse the other poster mentioned on mine appears to be fine. I was able to test the continuity across it on the back of the board and had 0 resistance.



and

[zac_haryy]

Re: Chimei DAC-19M009 Power Supply problems

Hey all, new to the forum but having close to the same issue. When I plug in the monitor I get a green light and a high pitch noise and then after a bit (5 seconds) the screen turns gray. I was trying to figure out what part on the power supply this was? I have tried doing a little research on a bridge rectifier or find out which part that is but have had no luck. Anyways some help would be great!!

-haryy

[PlainBill]

Re: Chimei DAC-19M009 Power Supply problems

hello all this is my first post here and im sorry top revive an old thread but i thought it best seeing as though i have issues with this exact power supply

im getting 350vdc at the cap tried unsoldering the fuse no change
in the area in blue there is a 13.8v out put which is reading 14.29v
but the 2 outputs marked 5v are reading nothing
any help in this matter would be greatly appreciated

I assume you are in an area where line (mains) voltage is about 240 VAC.

Troubleshooting this would be much easier if we had sharp, clear pictures of both front and back sides of the board. Take the pictures in a well lit room and turn the flash off. It will probably be necessary to trace out part of the circuit.

Also, post a picture of the connector indicating the voltages specified and the voltages you found.

PlainBill