smallstone issue J clone not working

[gez]

Incidentally, your pin5s should be a diode drop above ground (0.6-0.7V), so that's what you're aiming for.

[nathan Dodd]

i'll keep scraping away - well... i will soon. the misses hates it when the attention's devided lol. i'l check again and keep you updated. thanks for all the help so far!

[nathan Dodd]

all the tracks seem clear - tomorrow i'll check the IC sockets - i've got this feeling. g'nite

[nathan Dodd]

a question about R24:

it's 100 ohms on the schem, parts layout and component list everything - it's definately 100ohms and not 100k isn't it

(too much time to think during the day)

[gez]

it's definately 100ohms and not 100k isn't it

I've never owned or built this version but it says that on the schematic.  It looks like the LFO's output is a current source not voltage (hence the low value resistor).

[nathan Dodd]

I owe you a pint after this one! â€" scratch that I owe you a brewery. I can’t express my gratitude for your help and perseverance. Thanks a million again.

[nathan Dodd]

ok another day another scinario

from ground to pin 5 is 0.11 on ic 1-4

from R24 it's -0.04

ic 5 today is pin 5 = 1.83

pin 6 = 0.16

i've changed the chips around - does this say dicky chip to you?

[gez]

from ground to pin 5 is 0.11 on ic 1-4

This voltage is too low.  What I would do is pull R24 for the moment, take the ICs out of the sockets and measure the resistance between  the trace(s) that lead to the pin5s and ground (don't need to power circuit up to do this).  It should be infinite.  If you measure high resistance then you have a bridge somewhere (might be a hairline slither of copper/solder splatter between traces).  

If resistance is infinite then one (or all) of the ICs might be causing the problem.  Easy enough to check for, but first things first...

[nathan Dodd]

R24 Removed. IC's removed. meauring O resistance to all pin 5's.

[gez]

R24 Removed. IC's removed. meauring O resistance to all pin 5's.

Do you mean 0 ohms, ie there's a short between the pin5s and ground, or do you mean no figure shows up on your meter, i.e. resistance is infinite?

If you mean 0ohms then you have a short somewhere.  Scrape between traces and look for solder bridges.  I had this problem the other week and had to pull quite a number of components to find out where the bridge was.  Keep checking resistance until it's infinite.

If you meant infinite resistance there are a number of ways to check the ICs, but seeing as they're socketed my preference would be to simply breadboard the first stage of the circuit and test each chip one at a time.

Use R1/R3 divider plus C1 as Vbias.  Connect pin5 to V+ via a 15k resistor and measure pins 2,3 & 6.  They should all bias up at around the same voltage (Vbias).  Also measure voltage at pin5.

[puretube]

my switch and perticularly the wire bottom right going to it are hyper sensative, is this normal - when you go near it or touch it it buzzes like hell...

very strange in a nearly unity gain circuit - switch wired correctly?
Both jacks connected to circuit ground when on and when bypassed?

(here`s not knowing which switch, and what "wire bottom right going to it"
means...)

[nathan Dodd]

sorry i didn't get a chance to reply last night - i'll be back on the case tonight

[nathan Dodd]

Puretube:

It’s footswitchless at the moment â€" I decided to test it before I switched up and I’m glad I did, more wires would fry my nut. The buzz/hum is on the colour switch and it’s almost like a hypersensitive amplified ground buzz like grabbing hold of the tip of a jack plugged into an amp only heavier.

Yup both jacks definitely grounded

Gez:

I had some one else type for me yesterday I’ll clarify.

Around the track to all pin5’s of IC 1-4 I have 0ohms resistance. From behind where R24 was, from ground and from various other parts of the circuit I get the infinite reading â€" no ground leaks there.

As I say the LFO was giving me different voltage readings yesterday although I was getting some voltage to the other pin 5s. This circuit’s driving me nuts!

On a brighter note I built the Rebote2 delay yesterday as my second effect and it worked first time!!

If it comes to it I may etch a new board and start again from the ground up.

[gez]

I had some one else type for me yesterday I’ll clarify..

Ahh, that old chestnut!  

Around the track to all pin5’s of IC 1-4 I have 0ohms resistance.

There's your problem (or at least one of them).  I don't know what the layout is, but there must me a trace nearby to the one supplying the pin5s that is connected to ground.  Look for bridges between the two.  Keep the ICs out of their sockets and R24 pulled and keep checking resistance periodically until you've isolated the problem.

Edit:  Hang on, do you mean 0ohms resistance between this track and ground?  Or are you just checking the continuity of the trace connecting up all the pin5s?  You need to check the resistance between one of the pin 5 connections and ground.

[nathan Dodd]

Ok, I checked 2 things last night:

From ground to the pin 5s were infinite.

I also checked the continuity by checking between all the pin 5s to just before R24 this gave me 0ohms.



i also noticed one of my pin 5 pins on my IC socket was proud of the rest - it's still sticking through the solder underneath but i'll seat it properly tonight.

[gez]

From ground to the pin 5s were infinite

OK, red herring.  The problem is either with one or all of the ICs used for the phase stages, your LFO (not sourcing enough current) or both.

Best to check all the ICs out of cirucit on a breadboard.

[nathan Dodd]

Ok, I have no breadboard. I’ve got some old stripboard I’ll use. Something for tonight anyway

Use R1/R3 divider plus C1 as Vbias. Connect pin5 to V+ via a 15k resistor and measure pins 2,3 & 6. They should all bias up at around the same voltage (Vbias). Also measure voltage at pin5.

So:

Get myself an IC socket, connect a 15k (say R3) res to pin 5 of the socket and V+ to that.
Also connect a 10k (say R1) res followed by a 33uf cap (c1) to pin 4.
Then measure voltage between pins 2,3&6 to pin 4?
Have I got it?

[puretube]

"I also noticed one of my pin 5 pins on my IC socket was proud of the rest - it's still sticking through the solder underneath but i'll seat it properly tonight."

sorry for interfering, but my British is not the best; what does this mean?
that the socket-pin is not properly soldered to the PCB-pad?
:?

[nathan Dodd]

connectivity is fine but some times the pins in my IC sockets move up and down a little. one of em's done that - that's all  :wink:

[nathan Dodd]

is what i put in the post before last what i should do?