Circuit revival

[stolenfat]

So, as an experienced bender i know most the tricks to revive a dead circuit, but im so desperate to get my keyboard back alive that i couldnt resist posting.

I have spent about 30 hours on this old Yamaha PSS-470 and it sounded amazing, purely amazing and i was absolutely stoked to include it into my main arsenal as a glitch rhythm machine.

I had implemented about 20 switches, buttons, and a control voltage input.

The thing runs on a couple C batteries but i fed in a 9volt while bending it, cause who the hell has c batteries. Once I was done and it was all working well. I decided to run it with it's AC adapter because the 9volts got drained in about 40 mins or so.

Heres where shit hit the fan, as soon as i turned it on, it made a big sound, which i figured was just the bend switches and all, so i reset all the switches to off, and tried it again. It turned on, but no keys or buttons worked. I could not get the demo going, but some of my huge distortion bends would still crank out drones and fuzz. But all the other switches, which played on the internal drum stuff didnt work at all.

buuuuhhhhh


So, heres where I decided to recheck the circuit. i didnt notice any blown out components- no burns that werent all ready there from solder iron mishaps. No two solder nodes accidently connectted together. No exploded parts.....

What im thinking is, maybe an IC got ruined? Maybe I ran positive power through the voltage out?

There is also a crystal oscillator on the board, I've read that these often can cause problems, maybe it should be replaced?

any body out there an authority on this board and might know something?
Any sympathy from other benders who've slaved over a circuit just to have it die just as your finished?

I should have never ran it back on ac power! Foolish!

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[stolenfat]

well hey, i just noticed this... theres a diode which looks much darker than all the other diodes on the board... maybe thats the problem... but why would a bad diode affect things like that?
ya think?

[stolenfat]

well despite it's unquestionable amazingness, i decided to scrape the poor boy for parts....
too bad

[badstatic]

such a shame....

I had a casio sk200, which I spent weeks bending. Worked really well for a while and then just DIED on me. At the time I didn't know anything about electronics, but looking back on it I reckon all I would have had to do was replace a busted diode.

sadly I sold it on ebay, and now some other damn bender owns it.....

[Uncle Krunkus]

The problem with plugging a wall wart in is that the chances of reversing the polarity go up dramatically. Now, normally you might get away with it, but after adding much in the way of bends, (which are basically partial shorts to AC, or, if you don't use caps, DC) then the chances that reversed polarity is going to cause major problems go up even faster!

I don't know if BOSS started it, but the whole "we'll make the adaptor -ve tip so they have to buy our one (at five times the +ve tip price)" philosophy has got a lot to answer for.

What if we fucked with other standards to make a quick buck?
Marketing Executive : "We'll use special 9V batteries which have the nipples reversed! We can get them specially made in a factory in Taiwan! They could still have the standard 9V clips attached to them, but we'll write on everything that these ones are back the front!!"

While I'm at it,...... Why are USB devices polarised? There's only 4 connections in there for christsake! What? That would make it mechanically unsound you say? Like more unsound than they are now?
Imagine being able to plug any USB cable or device in without thinking which way up it was?!?! My God!!!! it would be soooooo futuristic!!! Like Fucking Dr Who or something!!!!!

Okay, rant over.

Have a wonderful day!!

[richardc64]

[Uncle Krunkus]

There's nothing intuitive about SATAs. I almost broke the first one I handled.