Tonepad Small Stone Help Needed Please

[pakrat]

Also, I am getting voltage on pins 1 and 8 of IC's 1-5.... I still must have a bridge somewhere. I'm gonna go slice n' dice the board again.....

[chromesphere]

Pin 1 & 8 are NC = Not connected, according to the datasheet.  You should not be getting a voltage on those 2 pins.  Scratch around them and make sure their are no bridges.  I would also suggest scratching around EVERY SINGLE TRACK on the board to make sure their are no invisible solder bridges.  Has happened to me on a number of occassions.

I will check my voltages when i get home, which is shortly.

EDIT: infact the evidence would suggest a short.  Maybe try to find that first before i get those voltages.

Paul

[pakrat]

Ok, I have scraped all around pins 1 and 8 of all IC's, and I still get voltage on those pins. Here's what I have done: I put R2 back to stock 470 ohm for now, since that problem is probably related to my other problems. This board is now stock except for the volume drop mod. I then removed all IC's and tested pins 1 and 8 on all sockets.... 0.00v. One by one, I put an IC in socket 1 and tested pins 1 and 8, and there is voltage there! I tested 9 different IC's and all of them have the same readings. In fact, if I put an IC in ANY socket, I get voltage on pins 1 and 8. Is it possible ALL 9 of my IC's are bad? The voltage seems to be generated by the IC's themselves. I have pulled my remaining 2 hairs, and thanks to the small stone, I am now bald.......

[chromesphere]

Thats weird.  Im no pro, but i'm pretty sure you shouldnt get a voltage on 1 and 8.  Even my earlier voltage readings, didnt have a voltage reading on 1 and 8 (see my troubleshooting thread i posted earlier).  Theres no tracks on those pins!

4 things i could possibly think of.  1) i checked the pinout on the ca3080e and it seems the same as the ca3080a's.  Maybe they are not the same?  2) Maybe your 3080's are rip offs?  Where did you get them?  I have heard of counterfeit IC's being sold a number of times before.  Check the sellers feedback. If you have another pedal that uses a ca3080 (like the Ross compressor) test them in that.  3) There is excess voltage somewhere at the start of the circuit been driven into the OTA's and it's causing voltage to appear on pin's 1 and 8.  4) they are all broken (bad batch?)

I know this sounds tedious and unnecessary but i would still encourage you to scrape around ALL the tracks.  Every single track, remove the flux, make absolutely sure there are no connects betwen pads, but scrap everywhere, even if theres no solder joint near the track.  Scrap it.  you might have a minute connection somewhere.  Use a lamp and a magnifying glass if you have one, spend time going around methodically.  Do it twice.  Make sure you dont miss anything.

Let me know if you want those voltages, hopefully i should get some time tonight to check.
GL
Paul

[pakrat]

Thanks for stopping by again Paul. I cut every single place to cut, even if it was a mile away from anything else..... I can definitely rule out a short or bridge in the soldering at this point. Nothing has changed sadly, so once again I must blame this on the IC's. I don't have any home built pedals that use CA3080's either so I can't test them. Fake IC's.... they look to be Harris CA3080's, but I guess anything can be faked. The only thing that would cause voltage on pins 1/8 would be a short in the chip, since there is no voltage in those spots with the IC's removed. According to the datasheets, all of my transistors are oriented EBC and I double checked the layout for those orientations. I don't know what else to check at this point. I suppose there is no way to truly test one of these IC's unless I have another working unit that uses them. I did read in another post, that you can ignor the voltages on those pins if the circuit works... http://www.diystompboxes.com/smfforum/index.php?topic=37070.0;wap2
I just put all the IC's back in, and I'm actually getting voltage swings now, and with the pot turned about midway I get a ticking sound.... is it breathing??

[chromesphere]

Oh i see, i always thought NC meant completely disconnected from the internal circuit.  There you go.

Im sure i've heard of fake ca3080's before...this guy seems to think their around: http://huebnerie.de/blog/?p=88

Lets here it for voltage swings! Thats a start.  All that scratching paid off?  lol Hopefully i'll get a chance to measure some voltages tonite.

Paul

[pakrat]

I just did a lot of reading on these IC's, and they have been out of production for some time. I did get them from ebay as I'm sure a lot of people do to save some cash. Smallbear has 'em for about $5 ea. I guess I would be safer paying a little more and getting "legit" IC's. I have also been reading about alternatives to the CA3080e, but I need to research more. I would really appreciate some voltage readings Paul, and I also appreciate the time you have already put into helping me. You are truly an asset to this forum!

[chromesphere]

No problem mate.

Alright, heres my voltage readings for the IC's.  Hadnt used the pedal in a while, so tested it, and its working as it should so the readings are of a working pedal.  Some of these readings are a bit rough, cause the voltage is moving all over the place but should be enough for you to go on.

Dry Setting - Pot set to medium speed (middle of turn).

Supply: 9.11v (battery)

IC5

1 - 0
2 - 6
3 - 6.6
4 - 0
5 - 0.55
6 - 1.5 - 2.0 all over the place - oscillating
7 - 6.5 - 7.5 " "
8 - 0

IC1-4 (all roughly the same -> from my understanding, they should be roughly the same)

1 -0
2 - 2.7-3
3 - same as pin 2
4 - 0
5 - 0.62-0.66
6 - 3.67-3.9
7 - 6.5-7.5 approx
8 - 0

Hope that helps!
Paul

[pakrat]

Thanks for taking the time to get me those readings! After reading the feedback of the seller I got these IC's from, I must believe they are indeed counterfeit. I never thought someone would go through so much trouble to fake an IC, but apparently they do. Here is feedbak left by another user on ebay.... "Counterfeit Parts,This seller is Crooked, Stay Away, Thanks Ebay for refund - 10pcs CA3080E IC OPAMP TRANSCONDUCT 2MHZ 8-DIP". Those are the same ones I got. I have to tell ya, these things look totally authentic too. I mean, if the part numbers were written with a white marker or something, I would have suspected something. These look to have the correct marking on both sides of the chips.  I am going to order replacements from smallbear today so I can be sure to get authentic CA3080's. I really appreciate your help Paul, and hopefully someone else can get help from all of this..... especially correct voltages for this thing. I will post my findings when the IC's arrive. Thanks again!

[chromesphere]

Bummer to hear its looking like dodgy IC's, great to hear you could have found the problem though!  Low life scum bags.  They have no idea how much frustration they cause.  It has nothing to do with 10 bucks or whatever they cost.  You get a refund, so its all good.  Its the 8-10...20+ hours diagnosing a working pedal, when the IC's are fake...makes my blood boil.

As a curtosy to the other members on the forum i would like to suggest, once you have tested the small bear 3080's, "name and shame" this guy, start a new thread and link to the listing.  "stay away from these".  I sympathise for the next guy that buys from this a-hole.

Edit: you should google "identifying fake IC's" or something.  I'm sure i read somewhere that you can use acetone to take off the print on the IC, or something like that.  If the print comes off = Fake.

Anyway, good luck mate, i hope the replacements work!  Prepare yourself for some phase swirling awesomeness 
Paul

[pakrat]

Paul, you are correct about the acetone test.... I just took your suggestion and searched for info on fake IC's. There are a bunch of ways to check, but the examples I've seen look easier to spot compared to mine. I compared them all under my big magnifying lamp and I do see differences. They are all the same part # from the same manufacturer.... Harris, but the indents on the ends are definitely different from each other. I think I actually have 3 different "types", but I'm sure I'll know more when I recieve my authentic chips from smallbear. Oh, and the markings do not come off with acetone, they look to be etched or engraved in. If these are fake, they must be really good ones....

[PRR]

> If these are fake, they must be really good ones....

The machine Harris (and everybody) used to mark ICs in the 1980s is probably now in China, picked-up in a yard-sale when Harris (and everybody) moved to newer machinery and sold-off their older machinery.

So it could be a totally genuine marking on some OTHER chip.

I just think it is so odd that there is any other chip which gives nearly-right voltages in a '3080 socket.

[chromesphere]

Yeah they are, sort of around the same ballpark as my voltages, bar pin 8.  Probably should wait for those smallbear ic's to show up before we start lynching people let us know how you go!
Paul

[pakrat]

Yeah I'm definitely not looking to lynch anyone. The chips look authentic to me, but there are 2 that are different from the rest, and plenty of his feedback had the words "fake' and "counterfeit". I don't have enough experience to make any judgements. If the ones from smallbear give me the same results, I guess it's not the worst thing to have extra 3080's lying around. Do either of you guys know what would cause a 3080 to have voltage on pin 8, when it isn't connected to anything? Paul R isn't allowed to say "because it IS connected to something"

[chromesphere]

Yeah its a strange one.  I think the only way you will know is when you test the small bear ca3080s. Or atleast it will be looking even more so like they are fakes.  May i ask the cost?  Were they crazy cheap?

The pin 8 voltage is a question for PRR im afraid.  I have no idea.

Paul

[pakrat]

Take a look at this:





The indents are not the same.... Does that mean anything?

[pakrat]

Unfourtunately, they were 5 bucks a pop. Even worse, I also got a bunch of AD823AN's to upgrade a Bellari tube compressor I have, same seller. Hey, maybe those are re-branded 3080's! 

[chromesphere]

Hey, maybe those are re-branded 3080's! 

LOL!

Gee, 5 bucks each...i bought mine about a year ago, they were about 2 bucks each for 5?   Probably doesnt mean anything if the guys just trying to get $$$ though...

Unfortunately i have never even SEEN a fake IC before so i cant comment.  I could take a photo of my ca3080's at home if you want to compare?  their socketed so i can pull one out easily enough.  (*snap* "FFFUUUUU.....") lol

[pakrat]

Thanks for the offer Paul, really. I wouldn't want to jeopardize your working small stone.....
Here's a better look, maybe compare these to yours:



The one on the left kinda looks "blacktopped" now that I see it so zoomed in. Look at the indents too, totally different.

[chromesphere]

Not just the notch  / indent, but the entire thing...you could tell me they were different IC's and i would believe you.  The texture of the black housing, those 2 metal bits in the center of each IC (ones copper color the other is silver), even the legs look different....but...what if the manufacturing process changed at some point in the ca3080E's life though?  Still not conclusive...its a tough one.  Maybe thats why the counterfiet them.

Ill check my ic's tonight.  I think my ca3080's came in a tube.  It looked like the just slice the tube depending on how many you want.

Paul