Help needed to ID 70413080 chip

[andy123]

Hi All,

I have come across some old peavey boards and have been raiding them for parts.

It has a chip which I'm having trouble identifying. It's an 8 pin dip and is marked with

H     
70413080
H9431

I did some googling and think it could be a ca3080. The "H"  maybe the Harris logo.
I'm guessing the H9431 is the date code. That just leaves the 70413080.

Can anyone confirm or deny that it's same or related to the ca3080?

Any help would be appreciated.

TIA    Andy

[Mark Hammer]

You can always turn to the pins and pads to tell you stuff.  For instance if it's a dual op-amp, then there will be something bridging pins 1 and 2 and something else bridging pins 7 and 6.  There is a good chance as well that pins 3 and 5 will be tied to ground, either directly or through a resistor.  If it's a 3080 then there likely won't be anything bridging pins 2 and 6 directly (which you would expect if it was a single op-amp) or bridging pins 6 and 7 (which you would expect if it was a dual op-amp).

Powewr connections are another good indicator.  V+ goes to pin 7 on 741-type and 3080, and to pin 8 on 4558 type.

[andy123]

Hi Mark,

Good idea! Am looking at the board right now.

-Pins 7 and 8 are shorted  and seem to be connected to a V+, (this seems to indicate a single OA)
-Pin 1 is connected to pin 6 which goes to pin 3 of a 4558.
-pin 2 and 3 are connected with a resistor (100 ohm) and pin 2 is not directly connected to pin 6
- nothing between 6 and 7 either.

Seems it's been narrowed down to a single op amp at least. 

Any ideas on decoding the numbers?

Cheers

Andy

[Mark Hammer]

That does not sound like a single op-amp to me.

There ARE other pin configurations (and I can check my map of them tonight if I remember), but normally, pins 1 and 8 are reserved for compensation (as seen in the Rat), such that they will either be left open or joined by a cap.  I can't think of any circumstance with an uncompensated single op-amp where pins 1 and 6 are linked UNLESS it is one of those unusual chips like the one used in the Boss DS-1 (TA7136).  My datasheets on that one show compensation via capacitor links between pins 1 and 6, and from pin 6 to pin 3 via a resistor.

Closer, but still not quite.  This may be a case for hauling out the NTE/ECG catalog and checking against their pinouts.

[jxoco]

-Pins 7 and 8 are shorted  and seem to be connected to a V+, (this seems to indicate a single OA)
-Pin 1 is connected to pin 6 which goes to pin 3 of a 4558.
-pin 2 and 3 are connected with a resistor (100 ohm) and pin 2 is not directly connected to pin 6
- nothing between 6 and 7 either.

looks like a 3080 to me.
pin 1 and 8 have no connection so discarding them 2 and 3 are input - and +. pin 4 ground or V-. pin 6 is the output, pin 7 is +V.
on a 3080 pin 5 controls its gain. In compressors pin 5 controls the clamping down on the signal. In tremolo circuits pin 5 is the low frequency oscillator.
Most likely it is a part of a tremolo circuit, I think.

3080's are very sensitive to static. you may ruin it just unsoldering it if your not grounded.

[andy123]

Thanks for the advice Mark and jxoce.

The chip is in a socket so easily removed so static shouldn't be a problem from desoldering.

The board contained a 4558 and 4560 as well as thiis one. I didn't recognise it and was just trying to quickly identify it to see if it is useful for any future projects.

Will look into it more if I have time..

Cheers Andy

[Mark Hammer]

Just out of curiosity, what is the Peavey product?  If it's an amp there is a good chance that the schem for it is posted around somewhere.  That should make identifying it pretty darn easy by comparison.

[andy123]

Etched on the board is "PV1.3K Drive" so I'm assuming it's from a Peavey pv1.3k

Had a google round and apparently it's a large power amp of some sort.. Couldn't find any schematics posted anywhere though. If I was really keen  I guess I could contact peavey themselves. Oh well....

Cheers Andy

[jxoco]

what about this one.

http://www.schematicheaven.com/newamps/peavey_microbass.pdf


U4 looks like a 3080 and it's in a compressor type of circuit for a bass

[andy123]

The setup of u4 look very similar to the chip on my boards. Does suggest that my mystery chip is a single OA.

Unfortunately it doesn't specify what u4 is.       Sadly I'm not experienced enough to recognise that it might be a 3080 type circuit


Definately helps though. Will put them in my spares spares box for another day.

Thanks

Andy

[Jamody]

70413080

13080 IC, 8-pin DIP, specially selected IC LM3080N or BA4560, for Peavey, replaces old # 70487478 and 87478, Do NOT use CA3080

http://www.vibroworld.com/parts/tech17.html

[armdnrdy]

I'll see your Peavey parts inventory list and raise you a Peavey parts cross reference list! 

http://www.ampix.org/albums/userpics/10003/PV_Semi_Cross_Ref.pdf