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-   -   Apple Cinema Display 23" (PCB Q49C or info about transistor) (http://www.ehmac.ca/showthread.php?t=84366)

chimo May 19th, 2011 11:25 AM

Quote:

Originally Posted by kkmanuele (Post 1095661)
hi guys!!
i have found this documents, vq9 is SC70!!!
but were i found this transistor??

SC70 is a case style. Those are not transistors in the diagram.

issic:
From the pics, the board seems to have at least three voltage regulator circuits.

The transistor that's blown seems to have some heat sinking (there are a few vias visible in sim's pic around the device. If thay are just for this transistor, then that can help narrow the search a bit.

Are there components on both sides?
Can you provide some better macro photos of the board that shows the traces and the top marks of the devices in that area?
Is the black connector a power connector?

kkmanuele May 19th, 2011 11:40 AM

replacing the transistor with two 1N4148 Dioni find 24 volts on the anode of a diode and 12 volts on the anode of the other diode. but to pin 7 V in the LM2672 can not find tension.

GlassOnion May 21st, 2011 02:25 PM

Quote:

Originally Posted by kkmanuele (Post 1095661)
hi guys!!
i have found this documents, vq9 is SC70!!!
but were i found this transistor??


http://www.gioiepergioco.com/foto/Cattura.JPG

Try Electronic Components Distributor | DigiKey Corp. | CA Home Page

bradkarhu Aug 10th, 2011 03:41 PM

My Q1 looks exactly the same as yours issic. The right side is blown off. What's left reads H6F and a partial U so I'm guess it's the H6FU9 that kkmanuele mentioned.

All I've been able to find is this information on H6:

Device = BCW89R
Manufacturer = Phi (Phillips)
Base = R (?)
Package = SOT23R

The 3rd char is F which refers to this:

___|G|___
|________|
. |D| . . . |S| (ignore the spacing dots)

What does the U9 refer to? Any clues what replacement part I need?

risck Mar 14th, 2012 11:42 AM

CFD 1081/1082 Transistor Q1
 
Quote:

Originally Posted by bradkarhu (Post 1120798)
My Q1 looks exactly the same as yours issic. The right side is blown off. What's left reads H6F and a partial U so I'm guess it's the H6FU9 that kkmanuele mentioned.

All I've been able to find is this information on H6:

Device = BCW89R
Manufacturer = Phi (Phillips)
Base = R (?)
Package = SOT23R

The 3rd char is F which refers to this:

___|G|___
|________|
. |D| . . . |S| (ignore the spacing dots)

What does the U9 refer to? Any clues what replacement part I need?


The thread i9s somewhat outdated, but I think there are many questions left.

I found this for Q1:

There are several codes referred here to Q1 like:

H6 FU9
HE VQ9
HF XS5

I think that only the first two letters are signicant together with the package
(SOT-23 or 2.9 x 1.5 mm).

H6 should be a pnp-Transistor like BCW89R, but Q1 is not pnp.

HE may be a npn-transistor 2SC3123 or 2SC4250 (Toshiba).
HF is similar 2SC3124 (Toshiba)

The three following letters ar not significant.

I think this information may help someone out there.

hexdiy Apr 1st, 2012 11:25 AM

Vielen Dank, Herr risck. I think I have to add the ID of my "Q1" to the list: HEZ H4 According to this link, H4 is: a BCW69R, a BC177A equivalent in a SOT23R package. H6 is: a BCW89R, a BC556 equivalent, also in a SOT23R package. Both the BC177A and the BC556 come in a TO-92 package.
I believe a 2N4403 will do also, but please do check the specsheets! SOT23 equivalent of this reads 2T.
Both H4 and H6 are PNP, but in a reversed package. Could this be the reason for your remark
Quote:

H6 should be a pnp-Transistor like BCW89R, but Q1 is not pnp
?
Whichever equivalent you use, be very sure to mind the difference in pinout for the different packages!
Anyhow, I will be acting on these specs presently and post the results ASAP.
Thanks again for your post!

drewreece Apr 1st, 2012 01:34 PM

Hey,
Welovemacs has this board…
0171-2242-1471 20" & 23" Apple Aluminum Cinema Display Main Inverter Board
It claims to be an inverter board, but the picture is the main board, worth confirming if you are interested in getting the entire board.

issic's old ebay link had a few main boards on sale…
Apple | eBay

I have this bad picture I took when I fixed a different LDO on a friends 23" ACD…
http://dl.dropbox.com/u/59660/IMG_1608.JPG
I can't identify the ic from the picture, sorry.

I have a working 23" display but I haven't opened it at all, I don't know if it would actually help to have another pic of the component? Isn't the main problem identifying the part from the info printed on it?
I guess I could put a meter across it to see what it's operating voltage is but is everyone sure what type of component it is?

I don't really want to short out an unknown component in a working display.

hexdiy Apr 1st, 2012 09:03 PM

Thanks, Drew! Just so you know: I am very intrigued by this ACD issue, and by sheer stubbornness I've been at mine all day. Not that I am really in need of a 20" or 22" lcd display, I just want to know.
I do not really want to spend more money on it (only spent 30€ in the first place), I just want to get the component level repair done properly, and in doing so, maybe find out what is bugging such an awful lot of these machines.
Quote:

Isn't the main problem identifying the part from the info printed on it?
Indeed, for the main part it is: SMD nicknames are quite a bother to decipher! Although I am now fairly sure Q1 on my ACD 20" is either an H4 or H6 transistor, meaning a simple BC177A or BC556 equivalent in a SOT23R package. In my last post I was mistaken: although the BC556 indeed comes in a TO-92 package, the BC177A seems to be dressed in an ancient TO-18 full metal jacket :-)
The issue right now is the pinout for SOT 23R: on the Net, e.g. there seem to be circulating faulty pinouts in different locations. Whereas the right one, I think is just the mirror image of the SOT 23 (confirmed by this quote:
Quote:

Reverse joggle devices do present a few problems. They oftern have an 'R' in the type number. A reverse
package is one where the lead have been bent up instead of down. So it's a mirror image of a conventional
device. Identification is usually possible from the code number, but some manufacturers use the same code. In
these cases, it's a case of looking at the device with a magnifying glass. The leads of most normal packages
come out closer to the circuit board side of the device; conversely a reverse joggle package will have them
coming out closer to the 'top' of the device.
So following this logic, the right pinout will read in my opinion: top/id print view; Collector on top, Emitter bottom left, Base bottom right.
Please do not harm any component in a working display on my account! I am just experimenting with a faulty display mainly out of curiosity. With an eventual bonus of having a working specimen, of course.
A pretty good picture of the whereabouts of Q1 in question have already been posted earlier in this thread.
Anyhow, thanks an awful lot for your kind cooperation! I intend to get to the bottom of this, but do not follow my folly if you have a regular dayjob!

risck Apr 2nd, 2012 07:28 AM

Q1 Code
 
Quote:

Originally Posted by hexdiy (Post 1183667)
my "Q1" to the list: HEZ H4

I think your "Q1" reads "HExxx" not "xxxH4".

On my board "Q1" is "HEXS5" and definetely not a reverse package, since the leads are near the board.

hexdiy Apr 3rd, 2012 10:14 AM

Sorry for my persistance, but given these specs of the2SC3123:
Quote:

Type Designator: 2SC3123
Material of transistor: Si
Polarity: npn
Maximum collector power dissipation (Pc): 150mW
Maximum collector-base voltage (Ucb): 18V
Maximum collector-emitter voltage (Uce): 20V
Maximum emitter-base voltage (Ueb): 3V
Maximum collector current (Ic max): 50mA
Maximum junction temperature (Tj): 180°C
Transition frequency (ft): 900MHz
Collector capacitance (Cc), Pf: 0.5
Forward current transfer ratio (hFE), min/max: 40/300
Manufacturer of 2SC3123 transistor: TOSHIBA
Package of 2SC3123 transistor: TO236
Application: RF, Medium Power General Purpose
,
and seeing one of its contacts are connected directly to the 24.675 V of the powerbrick, I think it should immediately blow up. Or am I completely mistaken?
Also, the form factor does not seem right.
Moreover, why am I unable to locate any HE or HF types in different SMD codebooks?
Great thanks for thinking along, BTW!


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