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WIGGLING 'LITE' IN GUEST MODE

Magic Smoke!
MUFF WIGGLER Forum Index -> Music Tech DIY Goto page 1, 2  Next [all]
Author Magic Smoke!
haricots
Ok, so I've managed to blow up my second module ... this time I was building Fonitroniks Seq. Switch. Turned it on and one step LED lit up and then poof! hmmm..... It looks like the 22R resistor used instead of a ferrite bead just after the positive part of the power input took a major hit (does that make sense, I'm a wannabe DIY'er BTW). F1 for those who've built the circuit.

My questions are:

1) does this resistor (or ferrite bead) actually protect the circuit in some way and not just filter out noise? If this is so then it took the hit and the rest of the circuit components should be ok ... I'm crossing my fingers on this one.

2) I don't have another 22R resistor or a ferrite bead at the moment. Is there any other value of resistor I can temporarily use?

3) did it blow up because I may have the polarity reversed?

seriously, i just don't get it
Roycie Roller
Could you put up some photos (of the power connection area/22R section of pcb & which way you put the connector on)?
Sounds like reversed polarity to me..
haricots
before I dig up a camera, let me illustrate. I think you are right and I put the put the power connector on backwards.



Circled in red is the blown resistor.

The power connector has the clip part at the bottom. I suspect it should have been at the top.

I used the motm style connector (mta 156, 4 pin) not the Euro 10 pin thingy - the board has room for both.
Luka
1. yes, the resistor hopefully took the impact and saved your mdoule
2. anything between 10 - 22 should be fine
3. perhaps

grab your multimeter and check that the correct polarity is hitting your ICs
also check to see if the rails are shorting to ground (this means you have a short somewhere)
Roycie Roller
haricots wrote:
before I dig up a camera, let me illustrate. I think you are right and I put the put the power connector on backwards.



Circled in red is the blown resistor.

The power connector has the clip part at the bottom. I suspect it should have been at the top.

I used the motm style connector (mta 156, 4 pin) not the Euro 10 pin thingy - the board has room for both.


There's the + symbol above the part you've circled in red, so if your - wire on your MTA connector went on that side, that would explain the blown part. I think the part should've protected the rest of the circuit, but i'm not sure.
sduck
BTW the plastic clip thing on the mta connector should be on the bottom/outside on this board, so it sounds like that's not the problem. Unless the wire connecting it is made wrong. Or there's a different problem up the line.

Do Luka's suggestion and check everything with a dmm for shorts. That's most likely the problem.
zthee
This sounds like a short.
fonik
my board reads about 175k between +V and GND. what do you measure?
haricots
Thanks for all the help - I will further investigate this tonight after I buy some spare 22r resistors.

Fonik (or anyone else), in your notes you say wire up square pads for the 0/I, I/O1 through 4 to the tip of the appropriate jack. Right beside it are two other pads. The closest one on the left is the same as the square pad, correct? So there is on need to wire this up as well? The farthest one connects to the sleeve, correct?



I'm not using the recommended Cliff sockets so I need to run wires to my 1/4" sockets.

Sorry for the awfully newbish questions guys. d'oh!
fonik
haricots wrote:
Fonik (or anyone else), in your notes you say wire up square pads for the 0/I, I/O1 through 4 to the tip of the appropriate jack. Right beside it are two other pads. The closest one on the left is the same as the square pad, correct? So there is on need to wire this up as well? The farthest one connects to the sleeve, correct?


you are correct. the green colored shape is an alternate footprint for MTA100 connectors (instead of the cliff sockets).
haricots
One of the stand offs was touching a bit of solder and that's what shorted it out. So, I've replaced the resistor and fired it up but step 3 does not light up - it's just skipped. Did I partially blow a chip or should I keep digging?

**update, step 2 seems a bit flaky too. If I don't have clock source plugged in the steps kind of jump around here and there. eek!

Anyone in Canada wanna fix this (and my non-tracking MFOS VCO) for me? help
fonik
haricots wrote:
One of the stand offs was touching a bit of solder and that's what shorted it out. So, I've replaced the resistor and fired it up but step 3 does not light up - it's just skipped. Did I partially blow a chip or should I keep digging?

**update, step 2 seems a bit flaky too. If I don't have clock source plugged in the steps kind of jump around here and there.

sounds like a grounding problem, at least for me.
check R15 with your multimeter. it ties the 4017s clock input to ground. one end should be connected to GND, the other end should be connected to 4017 pin 14.
how to you clock the module? your source and the module should share a common ground. my prototype showed the same behaviour until i noticed that i forgot to solder the inputs socket shaft.

Quote:
Anyone in Canada wanna fix this (and my non-tracking MFOS VCO) for me? help

if this is your first DIY project i would suggest to try to fix it by yourself, IMHO. with the help from the kind and helpful people of the community you will even learn this way.

the first thing i do when troubleshooting is necessary is to think about the problem. if this doesn't help hihi i <greenline> the circuit. i take a green pencil and my DMM and check all joints and make them green on the schematic. if all connections are correct, i check the values (not that easy on a PCB, since the components influence each other).
i did the majority of mistakes when wiring, sometimes wrong values and very very seldom faulty parts.
haricots
Thanks Matthias, I will give it a try tonight.

When you say check with a multimeter am I just looking for continuity or some sort of value?

I clock the module with a FR Mobius clock out to a multiple then into the Seq. Switch. It seems more stable timing wise when clocked but 2 doesn't always trigger, step 3 has never fired. Pressing the clock switch to advance steps doesn't always work either.

Sadly, this isn't my first module. Out of the 5 I've built so far two are not working 100%. I need to work on my troubleshooting skills for sure.
futuresoundsystems
You're not alone.

I fried the ass off a -12V voltage regulator last night... at least I hope it was that over the LFO module... I got the pinout of the reg wrong and it's only outputting -3V in it's current state (pun? seriously, i just don't get it ) so I'm pretty sure it's the reg.

I'll be honest and say it's the first time I've seen the smoke..... and this was one of the first times I've been majorly deep with checking shorts, etc. just to find I got the pinout wrong!
haricots
fonik wrote:
my board reads about 175k between +V and GND. what do you measure?


It reads 996k. Problem?
haricots
fonik wrote:

check R15 with your multimeter. it ties the 4017s clock input to ground. one end should be connected to GND, the other end should be connected to 4017 pin 14.


This shows 47k between GND and pin 14.
fonik
haricots wrote:
When you say check with a multimeter am I just looking for continuity or some sort of value?

for <greenlining> just check continuity.

Quote:
I clock the module with a FR Mobius clock out to a multiple then into the Seq. Switch. It seems more stable timing wise when clocked but 2 doesn't always trigger, step 3 has never fired.

does the LED of step 3 never light, or does the signal not go thru?

Quote:
Pressing the clock switch to advance steps doesn't always work either.

so there is a problem with the clocking anyways.
let's concentrate on this and don't think of the switch IC for now.

since you had a short the 4017 might have passed away. replace it to be shure to have working one.
haricots
Will do!

Upon further investigation I've noted that the 4017 chip that I used is labeled 74HCT4017N. Is this correct or did I buy the wrong one?

Also, I have a bunch of spare decade counters labeled CD40106BCN. Would this work as a replacement?
wetterberg
haricots wrote:
Will do!

Upon further investigation I've noted that the 4017 chip that I used is labeled 74HCT4017N. Is this correct or did I buy the wrong one?
"HCT" means +5v only...
http://en.wikipedia.org/wiki/Logic_family
- dunno if that's your problem, but I'd think so.
DGTom
& the 40106s you have aren't decade counters, they are Schmitt trigger inverters.

its always worth grabbing the datasheet for any chips you are using, makes working out what they are doing in the cct. alot easier;

http://www.datasheetcatalog.com/

Unless you get em for free, or as good as, always go with CD over the 74HCT types. Most CMOS chips will run off anything between 3V & 15V & are pretty robust.
haricots
Thanks DGTom. Yeah, they aren't even the same amount of pins.

Can some kind person tell me the exact part number/model number for this chip so I can hunt it down tomorrow at my somewhat local electronics shop?
DGTom
oops meant to mention that,

CD4017. The CD is the important part, should be ok with BC/BCN/BM suffix.

Grab a few spares, really usefull chip. With a bunch of transistors, pots & diodes you can build a 10 step seq. on stripboard, make a bunch & have Foniks Seq. Switch as the master controller love with even less parts & more 4017s you can make a bunch of dividers for odd (3/5/7) divisions.

nanners
haricots
so is this the little bugger? http://ca.mouser.com/Search/ProductDetail.aspx?qs=sGAEpiMZZMutXGli8Ay4 kHwp%252bBX5a6ewAyJ3eS6S%252bmY%3d
DGTom
that one is 40174

This is the guy;

http://au.mouser.com/Search/ProductDetail.aspx?qs=sGAEpiMZZMutXGli8Ay4 kNbfNa3EDx4xxz8kLaFY%2fSA%3d


scratch what I just said about the BM suffix, that appears to be SMT d'oh!
haricots
Thank you again DGTom. So many variations make part hunting very difficult and confusing to the uninitiated. I really wish I used sockets now. eek!

So out of curiosity, the original chip that I used will not work? Is this (apart from the short) the source of my problems?
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