Help identifying smd device please!

I have perhaps foolishly tackled the repair of my freeview box - Tvonics MDR-250 - for which no service information appears to be available. I'm an amateur, btw. (Fault is it's powering on and immediately shutting down repeatedly.)

I have a suspect component, marked Q700 on the PCB, suggesting that it's a transistor of some sort, and marked 654Z. I've tried googling for this part number but can't find any information.

Its a 6 legged device, and I don't know of any 6 legged types of transistor. The only alternative device I've come up with is an opto- isolator - though I don't know what the standard PCB identifier would be for one of these.

2 pairs of pins are connected together, so there are effectively 4 legs. It's in a very cramped part of the board (next to the power socket and what I think is a fuse on it's own little sub-board) so I can't really work anything out from what it's connected to.

Anyways, I need some info because it's either completely short circuit, or it's connected to something which is completely short circuit, and I can't do much unless I find out what the thing is.

Any suggestions welcome TIA Alexis

Reply to
alexis.happyphoenix
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It's probably dual transistors in a SOT pack. Searching Digikey will likely pull up dozens of contenders.

They can be dual npn, dual pnp or one of each. Dual MOSFETs also use the package. With two legs connected, they could be wired common-emitter for switching, push-pull for amplification (though not likely), or just about any combination of two transistors.

Unfortunately, it could also be a small IC like a single logic gate. Lots of stuff uses the SOT package nowadays.

Wish I could be more help.

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Reply to
Randy Day

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Ok that's a hundred percent more info than I had and makes a lot of sense. I am duly grateful :-)

Many thanks Alexis

Reply to
alexis.happyphoenix

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