/diy/ - Do It Yourself

>>474760
And btw what the hell is it

Seems to be a 78S08. You can replace it with 78M08 or plain old 7808. They will be in a different package, though. If you're feeling lucky, you can try 78L08, which is in the same package, but has lower current rating.
It's a voltage regulator. Just google 78S08 or the other types to see the pinout etc.

Btw, it wouldn't be a surprise if the regulator wasn't the only ruined component.

>>474760

>no reverse-polarity protection diode

Cheap Chinese scum.

>>474771 beat me to it. It's just a small linear voltage regulator. Any 5V regulator in that package (it's extremely common) will do, as long as it can dissipate at least 600mW of power.

And, yeah, there's a definite non-zero chance that chip got screwed up, too. It's probably less robust than that regulator.

>>474771

Cula bula thanks for the tips, if I can get it cheap I'll give it a shot. Bought a bunch of these walkies in America on holidays years ago (Cobra) . But buying components in Ireland ain't cheap...

>>474773
Certainly worried about that chip, aye... It's a real shame now tbh but not much to be done eh... Sure we'll give it a crack and if it works it works.

We'll see what happens when crush comes to crumble

>Any 5V regulator in that package

thats a '08 not and '05.

> thats a '08 not and '05.

true, but adding a couple of resistors can turn an '05 into an '08, a '10, a '20 or whatever you need.

>>474953

You shouldn't you use that with 78xx. If OP really can't find 7808 and needs some kludge, 317 works much better in that circuit. (duh)

> 317 works much better in that circuit. (duh)

and, it works better how? an LM317 is pretty much the same inside as a 7805, etc, except the reference diode is intentionally low-voltage so that you have a wide ranging output swing (1.25V to around 30V).

one area where the 7805 beats the 317 is in price, because of economies of scale. another area is that 7805s are easier to scrounge from old electronics coz they're more common.

>>475004

Unlike 7805, 317 has a low and nearly constant adjustment pin current, meaning that it'll maintain regulation much better and you won't need a trimmer to account the unknown adjustment current. It also consumes less power.
Since OP is going to buy the regulator in any case, these no need for that contraption.

>>474760
What you really need is to discover what torched that voltage regulator in the first place, otherwise you'll replace it and the same thing will happen.

>>475366

>Plugged an AC plug into this here DC receiver.

>>475004
For one thing the output of the 7805 circuit is not precise. The amount of ground current the part draws changes the output voltage. It might not matter if you are the slop that add a trimpot because you can't do math.

For people that calculate their values and put in a fixed valve resistors, a LM317 is recommended. BTW LM317 has better ripple rejection specs than the 78XX if someone actually read and understand the specs.

>>475471
Then you'd still better look downstrea of the regulator because when it fused it passed AC through it which may have torched other things too.

>>474760
8V positive regulator. Replacement equivalent MC78L08