Are you actually using an LM317 on the negative rail? Cause that’s a positive regulator… You need an LM337 for the negative side.
That would make sense but no, the lm337 is fine and set @ -12v. Hope I didn’t come across in my wordage as such.
Presently on the 3rd lm317t, this guy gets +17v @ the input but only +2:5 output. What is up with the adjustment branch of this circuit? I had to have spaced something here.
Quoting myself, “Unfortunately FC doesn’t seem to publish a schematic, so it’s hard to be certain what’s going on, but I presume the LM337 [or the LM317] is hooked up similarly to the datasheet, with the trimmer and the 1k being the voltage divider that controls the regulator.”
I suggest making the following measurements:
With trimmers adjusted fully clockwise measure resistance:
- From LM317 output pin (pin 2) to ground
- From LM317 adjustment pin (pin 1) to ground
- From LM337 output pin (pin 3) to ground ← NOTE OUTPUT PIN IS DIFFERENT
- From LM337 adjustment pin (pin 1) to ground
Then make the same four measurements with the trimmers adjusted fully counterclockwise, and report back.
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I’m a bit lost since you seem to have changed your mind about which rail is the problem, but I actually went through the trouble is tracing the thing out once, hope it is of help to you:
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Yep I got my polarities mixed in that initial post. It’s certainly the (+) side thanks for catching that.
Thank you for some direction, I’ll be in front of this thing in a bit and report back .
Here’s what I’ve gathered,
Clockwise / Counterclockwise as follows:
Lm317
Output pin. +2.52v / +1.80v
Adj. pin. +2.33v / +1.45v
Lm337
Output pin. -6.96v / -16.14v
Adj.pin. -5.70v / -15.06v
No, I meant measure resistance (with power off).
Hope I’m not in over my head here analogoutput but I have a feeling I could learn something here awesome
Measurements with my meters meter on gnd is trimmers set,
Clockwise lm317
Out to gnd. 2.58k
Adj to gnd. 2.50k
Clockwise lm337
Out to gnd. 1.21k
Adj to gnd. 0.99k
Counterclockwise lm317
Out to gnd. 1.10k
Adj to gnd. .92k
Counterclockwise lm337
Out to gnd. 3.16k
Adj to gnd. 3.04k
I guess that’s all kind of reasonable. In-circuit resistance measurements can be hard to interpret because there may be parallel resistance making things lower than expected, but your minimums are just below 1k from ADJ and about 220Ω larger from OUT, which is about what I’d expect from @TimMJN’s schematic, and on the LM337 side the maximum is about 2k higher, corresponding to the resistance of the trim pot. On the 317 side it’s only about 1.5k higher but that may be fine.
One thing that’s surprising is that according to you the LM337 side maximum is counterclockwise but the LM317 side maximum is clockwise. Is that a typo? Regardless I don’t think it means much.
In any case the R2/R1 ratio for the LM317 looks to be about 2.5k/0.2k = 12.5 to 0.9k/0.2k = 4.5 which should give a voltage range 1.25*(1+4.5) to 1.25*(1+12.5) = 6.9 V to 16.9 V. Pretty close to what you get on the LM337 side but not at all on the LM317 side. So the resistances are all right, and the output’s not shorted.
You say you’ve tried multiple regulators, were they all from the same supplier?
If it’s not bad regulators then I have no idea.
Thanks for pointing that out and giving me an idea of what to look for. I’ll get out the breadboard and see if the lm317’s are legit.
I bought a bojack multi pack of lm317/lm337 a few years ago from Amazon before I knew any better that’s been untouched till now.
Or get new pcb and new regulators lol
Update:
Bad Bojack lm317’s
I breadboarded a basic variable voltage power supply with one of the two 317’s I had left and the voltages traveled correctly. Zipped the Routemaster up and it worked. Instant relief 
Jezzzzum So many months this things been a mental Klingon … Feels good gettin this shit to work rite
If y’all got any of these BOJACKers at home test em.
I’d be kind of interested in a photo of one of these regulators showing what’s printed on it. How laughable is the logo?
I bought a Bojack multilayer monolithic capacitor set several years ago and those have been fine, or at least I’ve never traced a problem to one, but of course capacitors and ICs are very different things. Not saying these ICs are fake but fake ICs are certainly much more a problem than fake capacitors.
When it comes to power supplies especially, you don’t want to cheap out. Not worth the risk. Save money, sure, but only by comparison shopping reputable sources.
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Fake ICs, we got them 
Fake regulators, we got them
Fake electrolytic capacitors? Oh yes!
I guess ceramic capacitors are too cheap and small to fake, but who knows!
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