Sharp spike back up through .
Electronic fatigue, old components just say "I'm Done"

But also be aware there are some real winners on ebay such as these counterfeits. My last time buy parts from Intersil had 0049 date codes so I wouldn't trust anything newer than about 2001 or so. CA3081s should have RCA markings up until about 1990 (taken over by Harris in 1988), they should have Harris logos until 1999 when this product was spun off to Intersil, they should have Intersil logo for a brief period of time in 2000 before they were discontinued.
There are also some signetics SG3081s out there but they're not real common.

There are some valid ebay parts out there but be aware of parts like these that were supposedly made in 2012 - long after Intersil discontinued them.

CA3081_Maybe (resized).jpg

ebay.com link: 5PCS CA3081 DIP 16 General Purpose High NPN Transistor Arrays

tried these. All good so far. $2 a piece.

Unlike the eleleparts, those posted by jj44114 look quite reasonable. Proper date code, proper part number marking (there should not be an "E" suffix shown in the marking on that era of parts), and for those made in 2000 - there is an "MALAY" beneath the intersil logo (for Malasia). Those look almost identical to the leftovers that I have from when Intersil did their last time buy.

CA3081_Probably (resized).jpg

I think these are the last Intersil 3081 parts made. get em now.

Bally also used ULN2081 and one other part number I have come across which i can't remember... Maybe it was SK3550? Both of those probably just as obsolete if not more than CA3081. Looks like NTE916 / ECG916 same part as CA3081 too.

These transistor arrays normally cascade failure when the main driver goes. When just one circuit fails in a CA3081 you can cut the two bad legs off and install a 2n4401 straddling the chip. Bit of a hack job but works fine.
800d793e7b010f1fee2a1c96c704f5b40510761e (resized).jpg

Can't remember what brand name is the (2) logo is but they bought or got bought by Allegro at some point. I use TND903 diode arrays in another project and they have that same (2) logo or the Allegro logo depending on the date.

Sorry if this hijacks the thread- I can make a separate?

Rebuilding a Stern project solenoid driver board now. In one ca-3081 (U4), 5 of 7 of the array transistors are toast. The main driver transistors test ok. Just replace the array along with all the diodes?

A few other drive transistors related to a different array (U3) show that they were previously replaced. One array transistor there shows Open. Going to use barakandl "piggyback 2N4401 method" on that one. But change all those diodes too?

Leave all the resistors or change them? They test ok.

Thanks

If you are going to use one the 7x 2n4401 modules to replace a ca3081 no other modifications are needed.

You should not have to replace any diodes or resistors to install unless they are bad. The 330ohm resistor will burn up if the coil locks on, but it will likely be visibly burnt if there is a problem.

Thanks Andrew. Just wanted to make sure I protected the new array. I was surprised so much of it was pooched up without blowing the drivers.

Those chips are still out there as well as some correct subs. It would be better to replace the chip with the right one.