Name that surface mount device (HELP HELP HELP)

[MeBluEyz99]

I have done extensive searches through Surface Mount Code (4 hours) all unsuccesfull someone please tell the the manufacturer or its operation anything to help me conduct a better search its a semiconductor inside the triton 2 which im questioning due to low contrast text on the lcd displays thanks for your time....

[Acetronics]

Hi, Blueeyz ...

Looks like a general use NPN transistor... not so complicated !

Alain

[Malc C]

Typing FQz into Yahoo returned several hits, most of which listed FQzxxx as zener diode arrays.. but they didn't look like that component.

http://www.alldatasheet.com/category/F.html

[AndyOne]

Is it a SOT23 device or one of the smaller packages, if you know which one it will help to narrow it down because different packages can have the same marking but meaning completely different types of components.

Andy.

[Gary Warner]

I couldn't find the number you posted, per say (yes, they list FQ), but this (http://clivetec.superihost.com/SMD_Codes.htm) web site seems to be the best at SMD marking I've seen.

[MeBluEyz99]

here is a little more of the circuit for you guys....is the 301 a biasing resistor does this make it a transistor npn definite

[Malc C]

IF the LCD follows the Hitachi 44780 controller or equivalent pin 3 is normally used to set the contrast via a pot between the supply rails, and the wiper to pin 3.

Maybe this device simply applies a fixed voltage on pin 3 to set the contrast.

EDIT:
If you apply +5 to pin 3 of the LCD does the contrast improve ?

I once had a 16 chr x 2 line Hitachi 44780 controller that required a negative voltage on pin 3 to get good contrast... maybe this device inverted the supply to provide the required negative voltage ???

[sahilkit]

hi malc

i have a smd code-book and i could only find these on f F-Q,FtQ,FQAA.

code- device manf. base package leaded equivalent\data

F-Q 2PA1576Q-------phi------N----sot323----gp pnp sc70 hfe 120-270
FtQ 2PA1576Q-------phi------N----sot323----gp pnp sc70 hfe 120-270
FQAA MAX6328_R26_T--Max---ZV----sot23-----microproc -ve reset gen 2.500V

i hope these will be of help

sahil

[MeBluEyz99]

IF the LCD follows the Hitachi 44780 controller or equivalent pin 3 is normally used to set the contrast via a pot between the supply rails, and the wiper to pin 3.

Maybe this device simply applies a fixed voltage on pin 3 to set the contrast.

EDIT:
If you apply +5 to pin 3 of the LCD does the contrast improve ?

I once had a 16 chr x 2 line Hitachi 44780 controller that required a negative voltage on pin 3 to get good contrast... maybe this device inverted the supply to provide the required negative voltage ???

Im pretty definite that it isnt inverting the voltage to pin 3 but what does seem to be working is that if you bring the voltage to or close to 5v+ at pin 3 the data on the display is readable....I think there is to much of a drop in voltage from what i think may be a transistor (due to the biasing 301ohm resistor which sometimes gives away a transistors identity) i believe the manufacturer has put the wrong surface mount transistor in the contrast circuit...it simply drops to much voltage.

[MeBluEyz99]

Is anyone brave enough to open up a unit that they sent for repair to hobby services great planes whats the big deal anyway there is no way for them to tell if you opened up the unit or not it is 8 screws and no void labels there will never be a way to for them to tell if you did or not....take detailed pictures if possible to see how they repaired the unit.

[jeffs555]

The standard configuration for an SOT-23 transistor has the collector on the pin you show as 0 volts, the base where you show .306v, and the emitter where you show .989volts. That would indicate that it is a PNP transistor connected as an emitter follower and is working correctly(the emitter would stay about .75v higher than the base). There is probably a pull-up resistor on the emitter, either in the display or on the board. Increasing the value of the 301 resistor would increase the emitter voltage.

PS since the output voltage is controlled by the ratio of the two resistors, you could replace the 472 and 301 resistors with a 5k pot and have adjustable contrast.