Chimei CMV 221D - doesn't power on

[funkster]

Re: Chimei CMV 221D - doesn't power on

Thanks once again all you guys, I have ordered the 10 pack of regulators recommended on ebay by PlainBill. Should we consider this thread solved until they arrive which should be in around 1-2 weeks?

[PlainBill]

Re: Chimei CMV 221D - doesn't power on

a) I failed the ESP class in school...
a) There's this funny little field in the Member Profile form called LOCATION.
b) The cross reference info might help someone find the part. I found it on a RC model site.
d) All the ones on eBay (no matter what country) seem to come out of Hong Kong.
e) I AM Moriarty

Toast

Hmm, maybe you also failed the alphabet ( Your points are 'a', 'a', 'b', 'd', 'e' ). However, in the spirit of the season, here are the responses.

a) ALL guys fail intuition. Marriage solves that. I know no matter what goes wrong, it's my fault.

a) Yes there is. And you and I are nice enough to have filled in that field. Others haven't. I considered asking Topcat to make that field mandatory, but decided not to go there.

b) I found the specs by Googling the original part number. This gave that information that it was a 1A regulator. After that, there are dozens of sources.

d) Almost everything comes out of Hong Kong. According to the WSJ, next year they are going to start shipping babies to the US. Walmart is already planning on stocking them.

e) So who died at Reichenbach Falls?

PlainBill

[Toasty]

Re: Chimei CMV 221D - doesn't power on

a) I failed the ESP class in school...
a) There's this funny little field in the Member Profile form called LOCATION.
b) The cross reference info might help someone find the part. I found it on a RC model site.
d) All the ones on eBay (no matter what country) seem to come out of Hong Kong.
e) I AM Moriarty

Toast

[PlainBill]

Re: Chimei CMV 221D - doesn't power on

ST Micro. - LD1117AS33TR

DigiKey has it:

http://search.digikey.com/scripts/Dk...=497-1228-1-ND

as does Mouser:

http://www.mouser.com/ProductDetail/...XsRjw3YqNjM%3d

Toast

Really only practical if he's in the USA. Since he posted a search he made on eBay Australia, I suspect he's looking forward to Summer starting in a few weeks.

What!!!! You didn't read Sherlock Holmes when you were a kid?

PlainBill

[Toasty]

Re: Chimei CMV 221D - doesn't power on

ST Micro. - LD1117AS33TR

DigiKey has it:

http://search.digikey.com/scripts/Dk...=497-1228-1-ND

as does Mouser:

http://www.mouser.com/ProductDetail/...XsRjw3YqNjM%3d

Toast

[PlainBill]

Re: Chimei CMV 221D - doesn't power on

I thought I'd be a bit daring and bridge the two U6 & U7 +3.3V middle pins together with a wire so as to elevate the other from roughly 3.1V to 3.3V and the screeen shows picture now

My question is, is it okay to run like that, or should I get a replacement? & if I get a replacement can someone help me find an equivalent chip from ebay?

http://shop.ebay.com.au/i.html?_nkw=....c0.m270.l1313

Oh and thanks all your guys for your kind help these past days. *cough* where do I send the cheque haha

Definitely do NOT run with the jumper!!! If you had worked for me I would have boxed your ears for even considering it!!! Replace both of them. Either your meter is out of calibration, or both are defective. The spec on these chips is +- 1% of their rated output.

Some of the parts on eBay are correct, you want a part rated at 1A, not 800mA. Also, it must be the SOT-223 package, not TO-220 or some of the others. This auction combines factors I consider important - Correct part, Excellent feedback rating, low shipping cost.

Oh, and do NOT try using the monitor until the parts come in. There is always a chance of corrupting one of the memory chips on the logic board.

PlainBill

[alexanna]

Re: Chimei CMV 221D - doesn't power on

I thought I'd try and desolder the two U6 & U7 chips and swap them to see if it is indeed faulty and to see if the voltage changes to the other. As soon as I change it and plug the power back in, bingo the power light turns on & also screen turns on now I measure the voltages and for some reason both now are reading 3.3V, even the one that was reading 2.41V.

I then quickly plug in the DVI cable to see if it shows anything on the screen, but just my luck it only shows white on the screen now, no menus or anything

edit: to be exact the one that was fauly is now reading 3.17V, and then other now 3.26V

Which one is reading the 3.17,what position on the board?
Al.
sorry i missed your edit

[funkster]

Re: Chimei CMV 221D - doesn't power on

I thought I'd be a bit daring and bridge the two U6 & U7 +3.3V middle pins together with a wire so as to elevate the other from roughly 3.1V to 3.3V and the screeen shows picture now

My question is, is it okay to run like that, or should I get a replacement? & if I get a replacement can someone help me find an equivalent chip from ebay?

http://shop.ebay.com.au/i.html?_nkw=....c0.m270.l1313

Oh and thanks all your guys for your kind help these past days. *cough* where do I send the cheque haha

[funkster]

Re: Chimei CMV 221D - doesn't power on

white screen => recheck your cable connections from the logic card to the lcd panel. Make sure both sides are connected properly.

Even though, I hadn't disconnected them, I reseated them and measured some pins for resistance from the logic board to the screen and it seems okay. Still white screen though. Perhaps the U7 now at U6 position is still faulty reading @ 3.17V?

[retiredcaps]

Re: Chimei CMV 221D - doesn't power on

I then quickly plug in the DVI cable to see if it shows anything on the screen, but just my luck it only shows white on the screen now, no menus or anything

white screen => recheck your cable connections from the logic card to the lcd panel. Make sure both sides are connected properly.

[funkster]

Re: Chimei CMV 221D - doesn't power on

I thought I'd try and desolder the two U6 & U7 chips and swap them to see if it is indeed faulty and to see if the voltage changes to the other. As soon as I change it and plug the power back in, bingo the power light turns on & also screen turns on now I measure the voltages and for some reason both now are reading 3.3V, even the one that was reading 2.41V.

I then quickly plug in the DVI cable to see if it shows anything on the screen, but just my luck it only shows white on the screen now, no menus or anything

edit: to be exact the one that was fauly is now reading 3.17V, and then other now 3.26V

[funkster]

Re: Chimei CMV 221D - doesn't power on

Bingo!!! That's a winner. CAUTIOUSLY check it's temperature. It's output (the center pin) should be 3.3V. Either it's overloaded, or it's defective.

Is that some kind of regulator chip? If it wasn't defective would it still output 3.3V even though its getting 4.77V?

edit: I don't have any kind of thermometer to measure its temp, although while I ground myself and touch both U6 & U7 to compare, U7 seems ever so slightly warmer.

edit2: If I was to replace it with an equivalent from on of these: http://shop.ebay.com.au/i.html?LH_Av...1&_sop=2&_sc=1

Is it likeley that it could be fixed? Or is it likely that other components are fried in that circuit as well?

[PlainBill]

Re: Chimei CMV 221D - doesn't power on

Okay after realising that I was looking at the wrong board lol

F1 checks out as a short, so that must be okay.

U6 Part no. is "AMC1117" "-3.3 F0628J" The voltages from left to right pins are 0V, 3.27V, 4.99V.

U7 Part no. is the same as U6, voltage readings from left to right pins are 0V, 2.41V, 4.77V.

Bingo!!! That's a winner. CAUTIOUSLY check it's temperature. It's output (the center pin) should be 3.3V. Either it's overloaded, or it's defective.

PlainBill

[funkster]

Re: Chimei CMV 221D - doesn't power on

F1 (left side near the connector to the power supply) Check the resistance.

U6 (upper left corner) What is the part number? Check the voltage on the three legs (the tab is connected to the middle pin). Use the mounting screw near the top center as ground.

U7 (middle of board) Same steps as U6, but voltage may be different.

Okay after realising that I was looking at the wrong board lol

F1 checks out as a short, so that must be okay.

U6 Part no. is "AMC1117" "-3.3 F0628J" The voltages from left to right pins are 0V, 3.27V, 4.99V.

U7 Part no. is the same as U6, voltage readings from left to right pins are 0V, 2.41V, 4.77V.

[Toasty]

Re: Chimei CMV 221D - doesn't power on

See circled items in attached photo.

[funkster]

Re: Chimei CMV 221D - doesn't power on

Are you applying a video source to the VGA input? I've seen these not respond without it.

I haven't tried the vga input, but I have tried the DVI input. When I plug it in the computer makes that detection sound, so it seems to pick it up.

You must have the 5v and 12v from the power supply. If the main switcher is running, you should have both voltages

Well, I get +5V, and +13.8V pins going to the logic board as indicated on the power board. Main switcher? What is that?

What cap brand/series did you use to replace the little one I suggested before? For some reason it is -very- picky about that cap. That's why I suggested FC or FM. I had a nearly identical unit with a new Rubycon YXG there and it would not run. Replaced with an FM and it took off right away. It was a 22uF @ 50v, correct?
Toast

Hrmm, I guess I need to buy a proper capacitor then, as I used 2 x 10uF 50V capacitors in parallel, not sure what brand they are though as they where spare parts from something else.

[jetadm123]

Re: Chimei CMV 221D - doesn't power on

F1, U6, U7

I can't seem to find these labels anywhere?

Located on the logic card

[funkster]

Re: Chimei CMV 221D - doesn't power on

Can you provide the part number of the device circled in yellow?

Yes, from the top an down, "TIP122FP" "CCODL VW" "MAR 631" and then 2 logos "ST" & "e3" with a circle around it.

[funkster]

Re: Chimei CMV 221D - doesn't power on

It very well could be a bad logic card. Before replacing it, here are some points to check.

F1 (left side near the connector to the power supply) Check the resistance.

U6 (upper left corner) What is the part number? Check the voltage on the three legs (the tab is connected to the middle pin). Use the mounting screw near the top center as ground.

U7 (middle of board) Same steps as U6, but voltage may be different.

PlainBill

F1, U6, U7

I can't seem to find these labels anywhere?

[jetadm123]

Re: Chimei CMV 221D - doesn't power on

Can you provide the part number of the device circled in yellow?