RE: Electronic Experts Needed - Can You Help Me Figure Out What Size Resistor This Is? [electronics] [diy]
From 1990, I remember this ... Bad Boys Rant Over Young Girls But Violet Gives Willingly. Black=0, Brown=1, Red=2, Orange=3, Yellow=4, Green=5, Blue=6, Violet=7, Grey=8, White=9
So, I agree 10*10^3 = 10k with a 5% tolerance.
But ... I question whether the resistor is the cause or the symptom. From your picture, I would replace R3, R2 and Q3 with a suspicion that it was actually Q3 that went.
Q3's job is to act like a gas pedal. By putting a little pressure on the gas pedal, you can control a lot of horsepower. Similarily, by putting a small current on the base of that transistor, you control a lot of current on the emitter/collector.
The discoloring looks like a buried plane heated up enough to discolor the substrate. So, the weakest link may also have been in the circuit board. If you are comfortable with a soldering iron, I'd recommend pulling R2 and R3 out and measuring them with an ohmmeter to see if they are actually blown. (Maybe pulling out the good R2/3 from another power supply and compare) Is the bottom side of the circuit board discolored as well?
If you look at the face of Q3, you should be able to read the part number and can get a replacement from Digikey or similar.
Thanks so much for such amazing info... I love STEEM. Thanks again @gikitiki
So what do you think, here is the backside. Still worth trying to save this board? If so, should I just replace R3, or also R2 and Q3?
Would Q3 show any external signs, the picture doesn't do it justice... cause it looks fine. I can take a better pic if you'd like.
Your wisdom is appreciated.
It looks to me that the pins or Q3, R2 and R3 all got hotter than the melting point. I'd start by removing R2 and R3, then testing their resistance. If you have to buy replacements, I'd definitely buy 2-3 of each (they are cheap) and include Q3. It will likely cost more in shipping than the parts themselves.
Are there any other pins on the backside that don't have the nice smooth look? i.e. that might have also melted recently? Possibly a part that has a heatsink on it?
ps, you got a new follower, so when you make your next post I can support.
I like your style btw, I think you might be a multipotentialite @gikitiki
Cool.
I just noticed that you were one of the driving forces for #spud. I'm proud to say that I did my little part. :-)
And yes, I do consider myself a bit of a multipotentialite. I'd just never heard of the term. Tonight ... there will be Ted Talks!!
Thanks for the label. :-P
Yeah, It was new to me too until someone on Steem posted about it, I saw the Ted talk and then things made more sense. Cool stuff. Enjoy and again, thanks for the wisdom and advice.
As for the board, I don't really see anything else that could be suspect but then again I am untrained so not really 100% sure what I am looking for and I am getting older so my sight isn't what it used to, although these new cameras are amazing and help with that part. I included a pic of the back to see if you see anything that I might have missed.
And as for SPUD, yeah, I am a long time long term believer in STEEM, and this here reinforces that belief. Thank you again.
The rest looks good. I'd try swapping the 3 components and go from there.
https://www.digikey.com/products/en