Way Huge pcb...

Started by amz-fx, February 12, 2004, 06:58:14 PM

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amz-fx

Here is the bottom of a Way Huge pcb...



What's so interesting about this?  The IC is unmarked but from the layout I can guess that pins 4 and 11 are for the V+ and V- power connections...  but if you can locate the IC in the middle of the board, you'll see that neither of these pins are connected to anything!!!

Anyone want to take a guess what's happening here???

-Jack

Steve C

Hey, the other side of the Swollen Pickle!

Ry

My guess would be that it's a suprious component thrown in to stop people from tracing the effect and making clones.

Please let me know if I'm wrong, but I can't think of a way that an IC could work without electrons flowing...

Ry

Mr.Huge

I can!
But it's so much fun to watch y'all struggle with such a simple little thing.
-Mr. Huge
BEN:   Mos Eisley Spaceport. You will never find a more wretched hive of scum and villainy. We must be cautious.

LUKE:   But I was going into Toshi Station to pick up some power converters...

VADER:   I find your lack of faith disturbing.

amz-fx

QuotePlease let me know if I'm wrong, but I can't think of a way that an IC could work without electrons flowing...
You're wrong...  :)  hint - there are bias resistors on the inputs and outputs...

actually I played around with an idea like this but never got it working well...

-JACK

Rory

Its not acting as a transistor?

Steve C

I'm going to go out on a limb and say it's acting like a rectifier?

Peter Snowberg

Very cute Mr. Huge. ;)

I think I know what the trick is, but I would need to see the top to confirm my suspicion.

It's not the sort of thing you would want to do with a chip that supplies any real power if I have it correctly.

This is the first time I've seen the concept used in an actual product.

Take care,
-Peter
Eschew paradigm obfuscation

KarbonHed

Is it something like a 4007 with the individual mosfets used as clipping "diodes"?

Paul Perry (Frostwave)

Since some chips have 'protection' diodes from input & output pins to power rails, if you leave the "official" power pins disconnecrted, sometimes yu can get the chip to work.
I had a logic chip in a turned pin socket once, and one turned pin collar was missing! the chip leg (V+ as it happened!) just floated there, while the chip acted a bit flakey.

Dan N


amz-fx

Most of the opamp sections have voltages like this:

Inverting input:  0.67v
Noninverting:    25mv
Output pin:    4.7v

The inverting input is essentially a diode drop above ground and the noninverting is connected to ground through a 100 ohm resistor, so it's not surprising it is almost 0.   The pullup resistor on the output and the internal circuitry are balancing the output near 1/2 V+.

Knowing what the opamp could be is the key to understanding this...  :D

regards, Jack

Paul Perry (Frostwave)

This is why I was glad mr Huge didn't post the schematics... this way we're going to LEARN something! :D

Ed Rembold


Aharon

If I want to know what's inside of an effects box I go and rent it for $10 a month at my local music store.
Aharon
Aharon

RDV

Most boutique builders sand off the old ICs or smother them in goop, so renting does you little to no good.

Regards

RDV

Chris R

4069 hex inverter has a different pinout than most 14 pin quad op amps..

which would mean.. that the unused pins on the 4069 were

output #2 & input #5


Aharon

"Most boutique builders sand off the old ICs or smother them in goop, so renting does you little to no good. "
RDV


Some do some don't,older effects certainly don't have that problem.
Aharon
Aharon

Ed Rembold

My only other guess would be a transistor array chip,
making it a BMP like thing?
I dunno,  love the surface mount pulldown R.


Ed R.

Mr.Huge

You are very wise Grasshopper.
But answer me this… Why does the universe appear to have one time and three space dimensions?
Ha..HA..HAHAH…HA!
-Mr. Huge
BEN:   Mos Eisley Spaceport. You will never find a more wretched hive of scum and villainy. We must be cautious.

LUKE:   But I was going into Toshi Station to pick up some power converters...

VADER:   I find your lack of faith disturbing.