negative range values on AIN J1 and J2

[dubphil]

Hello,

I have just build a new CORE (V3 from Mike), and when all the stuff is connected, the pots connected to AIN J1 and J2 have range values from -64 to 63. The pots connected to J3 are showing good range values (0 to 127).

I use an AIN module from SmashTV, everything seems to be well connected and soldered, where could I start to debug such a precise issue ?

Kind regards

Philippe

[dubphil]

additionnal information : if I connect the unit to MIOS Studio, the range value are 1 to 126 I can't reach 0 or 127 so the range differs from the one display on the LCD.

another thing I have noticed that about several cc events are happening when I switch on the unit during about 20 seconds even if I don't touch to any pots, then arbitrarily one CC event happens, the channel concerned is not always the same, And finally when I turn the pot of a channel, sometimes other channels are giving CC events, and if I leave the pots the channel continue to give CC events during few seconds.

I just want to say that before building the Mike CORE V3 I have used a SmashTV CORE where Anolog input where perfectly working (unfortunatly not the digital inputs), so all the pots connections to AIN module and ground haven't been touched.

Thanks in advance for your kind help.

Philippe

[jbartee]

I'm not sure about the missing step in -64 to 63 or 0 to 126, but the spurious CC's sound like a noise issue. Have you grounded all unused analog inputs on the AIN module? If you have and the issue persists, it's possible that the wires you're running to the pots are too long, cross something introducing interference, or both. The length of the wire might also be producing a small voltage drop, which *could* explain your missing steps as well.

[jbartee]

just to clarify what I mean:

http://www.ucapps.de/mbhp/auaimbctg.pdf

[dubphil]

just to clarify what I mean:

http://www.ucapps.de/mbhp/auaimbctg.pdf

yeah thanks a lot jbartee ! the schematic you point me was very precious to resolve the thing, I hadn't connect the Vs pin of J5 to ground (that's was the cause of the spurious events) and I did connect the wrong pins of J5 to the the AIN module (that explain why I had a range from -64 to 63)

no more missing steps all the analogic part is perfect now :)

Not the same for the DIN module : after two build of the SmashTV core and 1 build of the Mike core, I have always voltage < 4V at the J9:SI pin when I use the SRIO_interconnection_testV2 (without the DIN module connected to the CORE).

It would be evil that I always fall in soldering something well that would result to the same issue isn't it ? there is certainly something odd that should alert Törsten.

I'm very open to check what you want me to check to find the problem, I can also send the SmashTV CORE to someone for debugging.

nevertheless thanks a lot for your kind help jbartee !

Philippe

[jbartee]

yeah thanks a lot jbartee ! the schematic you point me was very precious to resolve the thing, I hadn't connect the Vs pin of J5 to ground (that's was the cause of the spurious events) and I did connect the wrong pins of J5 to the the AIN module (that explain why I had a range from -64 to 63)

no more missing steps all the analogic part is perfect now :)

Not the same for the DIN module : after two build of the SmashTV core and 1 build of the Mike core, I have always voltage < 4V at the J9:SI pin when I use the SRIO_interconnection_testV2 (without the DIN module connected to the CORE).

It would be evil that I always fall in soldering something well that would result to the same issue isn't it ? there is certainly something odd that should alert Törsten.

I'm very open to check what you want me to check to find the problem, I can also send the SmashTV CORE to someone for debugging.

nevertheless thanks a lot for your kind help jbartee !

Philippe

Glad the analog inputs are working properly!

as you can see from this schematic, J9:SI runs through R9, which should be a 10k pull up resistor. Unless there's something wrong with your power rail further up stream (do you measure 5v at other points on the board?), I'd start by double checking your work around R9.

[dubphil]

in fact with the 2 SmashTV's CORE and the Mike's CORE I've build I have the same issue describe in this post here :

on the Mike's CORE I have the 5V on the postion where Törsten advice to check here : http://www.ucapps.de/mbhp_core.html

I have 5v just before R9 and less than 4v after at RD1 of the PIC and J9:SI.

I'm not an electronicien as you can see, and I use a cheap analog multimeter (but it show me 5v where I should find it at others points).

by the way, the MIDIO128 doesn't show events from my buttons when I press them so there is something odd somewhere.

Thanks again.

Philippe

[jbartee]

in fact with the 2 SmashTV's CORE and the Mike's CORE I've build I have the same issue describe in this post here :

on the Mike's CORE I have the 5V on the postion where Törsten advice to check here : http://www.ucapps.de/mbhp_core.html

I have 5v just before R9 and less than 4v after at RD1 of the PIC and J9:SI.

I'm not an electronicien as you can see, and I use a cheap analog multimeter (but it show me 5v where I should find it at others points).

by the way, the MIDIO128 doesn't show events from my buttons when I press them so there is something odd somewhere.

Thanks again.

Philippe

Okay. Just in the interest of being absolutely sure, do you get the same measurements at RD1 and J9:SI when the PIC is removed?

It sounds like you've already narrowed it down; If you measure 5 volts before R9 and less than 4 directly after, then the problem must lay with R9, either at the solder joints or somewhere along the traces. Check for cold joints, reheat or desolder as necessary.

[dubphil]

Okay. Just in the interest of being absolutely sure, do you get the same measurements at RD1 and J9:SI when the PIC is removed?

I've just test it without the pic : I get the same measurements

It sounds like you've already narrowed it down; If you measure 5 volts before R9 and less than 4 directly after, then the problem must lay with R9, either at the solder joints or somewhere along the traces. Check for cold joints, reheat or desolder as necessary.

I have reheat, traces seams to be separated (by nude eye). Something I'm not sure, is it normal to find a short between J9:SI and VS of about 15 ohm ? (it is hard to mesure this more precisely with my cheap analog multimeter)

Thanks for your help jbartee

Philippe

[dubphil]

Please give me some help, I'm desperate with this issue since 2005 :(

[philetaylor]

That sounds like a "short" to me, There should be a very high resistance between SI and VS, as it has a 10K pullup, there shouldalso be 10K ohm between SI and VD. If you remove the PIC, does it still read 15ohm between SI and VS? if so there is a short somewhere on the board.

Cheers

Phil

Edited February 15, 2010 by philetaylor

[dubphil]

You must be right it is a short, I've the same measurements without the pic.

I'm damned with this CORE, I must admit that I'm not enough skilled to build such a unit : 3 builds 3 failed :(

Thanks a lot Phil

Philippe

[dubphil]

perhaps my last chance : here is a macro pic of my CORE : http://migratis.net/core.jpg

can somebody point me to the potential fault part ?

Thanks in advance

Philippe

[philetaylor]

Looking at the picture, it is quite messy under J9. It is quite possible that the "mess" is causing a short. I would try cleaning the PCB with an old toothbrush and some alcohol based cleaning solution first.

There are some other joints that appear to have a bit too much solder on which could be causing a "bridge".

A similar shot of the top of the PCB would also be useful (to make sure everything is in the right place!)

I don't want to make you feel even worse but I have built Cores from both Mike and SmashTV and never had a problem so i'm sure it is something that can be fixed :)

Cheers

Phil

[dubphil]

arf thanks Phil but I've just ruined the PCB by wanted to remove the to much solder on some joints, I will ask for Mike if he would be kind to mount it for me and I will pay the time by paypal.

Thanks again.

Philippe

[philetaylor]

When you say you have "ruined" the PCB. Do you mean that you have lifted a track (or 2)? This can usually be fixed with some link wire (or cut leads from other components). What type of soldering iron are you using? It may be too hot as you shouldn't lift tracks unless you left the iron on the track for a long time.

What is wrong with the other 2 CORE PCB's that you have failed to build? Do you still have them? It may be possible to fix one of those?

I really hate to give up on this sort of thing and I have repaired PCB's before that others wanted to throw away because they had burnt out or lifted tracks. The result never looks particularly neat but if it works, so what :)

Although the picture wasn't "that" clear, the soldering didn't look too bad to me, other than the common mistake of too much solder on some joints. A good joint should look like this, slightly rounded but not a "ball" of solder:

Cheers

Phil

[dubphil]

When you say you have "ruined" the PCB. Do you mean that you have lifted a track (or 2)?

yes I do and I have also connected tracks with solder and I'm unable to remove those bridges the solder is so thin than my solder pomp pomps nothing and when I scratch the bridges it lifts the tracks :(

it is quite a botch work :)

This can usually be fixed with some link wire (or cut leads from other components). What type of soldering iron are you using?

I use this one : http://www.lapanthera.hu/hu/doc/SOLOMON%20SR965.pdf . I don't know if it is 25W or 40W because it was part of a cheap soldering kit with pliers, wire cutters, a pomp and 1mm solder all this for only 30€ in 2005.

What is wrong with the other 2 CORE PCB's that you have failed to build? Do you still have them? It may be possible to fix one of those?

the first one (SmashTV pcb) is definitly dead, the voltage regulator is heating like hell and no more display and midi out/in.

the second one (SmashTV pcb)is always working well apart this J9:SI problem that shows less than 4V :(

Although the picture wasn't "that" clear, the soldering didn't look too bad to me, other than the common mistake of too much solder on some joints. A good joint should look like this, slightly rounded but not a "ball" of solder:

Yes I would very like to do such joint :)

perhaps I should acquire better soldering tools, can you advice me on a good soldering iron and solder for this type of build ?

Best and thanks for the time you spent to help me Phil.

ps: as I was afraid and I completely understand, Mike has no time to build the unit for his customers, so I will have to struggle myself...

Philippe

Edited February 18, 2010 by dubphil

[Janis1279]

the first one (SmashTV pcb) is definitly dead, the voltage regulator is heating like hell and no more display and midi out/in.

May be you will find some short circuit between the 5 volts DC power rails, only.

You can make measurements without PIC, LCD. If OK , connect it's again and compare results.

Regards, Janis

[dubphil]

May be you will find some short circuit between the 5 volts DC power rails, only.

You can make measurements without PIC, LCD. If OK , connect it's again and compare results.

Regards, Janis

Victory ! I did rescucitation of the dead PCB. as you suggest, I followed the 5V tracks and found solder that had overflow on the top side of the pcb but hidden by the body of a capacitor.

So now I have 3 CORE pcbs that shows the exactly same symptoms :

j9:SI at about 3,8V with and without the PIC, 5V is well measured upstream R9

J9:SI and VS with a resistance of about 20 Ohm (the Mike PCB as suggest Phil was messy around J9, but the SmashTV one's are really not messy).

I don't know why but I suspect that it is a reproductible error that I make, when I look to the SmashTV's PCB I'm more confident on the fact that the problem is not an arbitrary short won't you ? Does any arbitrary short leads to the same symptoms ?

Thanks !

Philippe

[philetaylor]

j9:SI at about 3,8V with and without the PIC, 5V is well measured upstream R9

J9:SI and VS with a resistance of about 20 Ohm (the Mike PCB as suggest Phil was messy around J9, but the SmashTV one's are really not messy).

If the PIC isn't installed, I really can't see how you can possibly have a short on all 3 CORE boards unless as you say, you have made the same mistake on all of them!

Looking at the circuit diagram for the core, J9:SI connects directly to pin 20 of the PIC and has a pullup to 5v via a 10K resistor (R9). It should have no connection at all to Vs. Looking at the quick view of the layout on ucapps.de, J9:SI looks to be connected by a very fine track which runs between the other pins so if you haven't been particularly careful with your soldering iron, it would be easy to accidently bridge some solder over the tracks.

Vs is the thick track that runs most of the way round the outside of the PCB so make sure that there is no solder bridge between J9:SI and it.

Thanks

Phil

Edited February 18, 2010 by philetaylor

[dubphil]

Vs is the thick track that runs most of the way round the outside of the PCB so make sure that there is no solder bridge between J9:SI and it.

Hi Phil, here is a pic of one of a SmashTV PCB, the traces you can see all around the solders is of course not solder, it is the transparent material that is often ejected of the solder when I burn it, do this material can make a bridge ? even if the SmashTV's PCB seems to be protected at the surface by an apparent plastic layer ?

Regards

Philippe

Edited February 19, 2010 by dubphil

[dubphil]

another experiment I did :

I have completely scrached the track to the J9:SI joint (and also removed the J9:SI pin but this is an accident of previous attempt to reduce the solder) and measure gives always 3.8V, is this possible ?

Best regards

Philippe

[philetaylor]

Hi Philippe.

The transparent material that comes out of the solder is called the flux. This is added to most solder to help it to bond to other metals. Often if you over-heat a connection, the flux disappears and that can cause a dry joint (one where the solder hasn't bonded correctly).

The PCB has what is called a solder mask, this is the protective coating over everything other than the solder pads which is an insulator.

It is difficult to tell whether there is a bridge without cleaning the excess flux off the PCB (get an old toothbrush), it does look like there could be one from the picture. There also seem to be lots of scratch marks around the pads as well which could have scratched through the solder mask.

EDIT: Yes you have really made a mess of the other PCB :(

Cheers

Phil

p.s. 500 posts, now I am a Guru !!!!!!

Edited February 19, 2010 by philetaylor

[philetaylor]

Also, to make you feel better. I may now "officially" be a Guru but I have made similar mistakes.... Here is a picture of the mess I made of one of my CORE32 PCB's:

On the left, you will see an aborted attempt at desoldering a regulator with a snapped pin (I bent it round and it snapped) My iron was too cold and I ripped two of the pads off. It isn't neat but I replaced the broken tracks with wire links further down the track.

On the bottom you will see the result of trying to remove one of the LCD sockets with the same crappy soldering iron. I lost so many pads that I haven't even bothered trying to sort this out as luckilly the PCB has 2 LCD sockets !

Other than having only 1 LCD socket and looking like a bag of sh*t, this CORE32 works perfectly

My point is, unless you really really screw up, most things are fixable

Phil

EDIT: I forgot to mention, I threw that soldering iron away. I would recommend a temp controlled soldering station, the best that you can afford!

Edited February 19, 2010 by philetaylor

[dubphil]

good job Phil, you give me hope :)

you didn't comment my experiment then, that means that it was useless to test such a thing ?

I did another thing, I bypassed the R9 and now I have well 5V on J9:SI, can I leave this resistor bypassed or it could hurt something in the circuit ?

Best regards

Philippe