Vintage ST/SGS-thomson component ID

[Cooldeepseaaudio]

 looking to identify this IC, it's most likely from the mid to late 70s and my own hunt has turned up nothing, I would expect it to most likely be some form of amplifier as it is used in a preamp circuit. 

Any help would be appreciated, thanks!

Fergus.

[Peter BENSCH]

Welcome @Cooldeepseaaudio, to the community!

The L150 was actually once produced by SGS-Ates, but no more information can be found. Old data books from 1974/75 or 1982 do not contain the L150 either, so it could be more recent.

However, it might help to analyse the circuit around the L150, which is most likely a single opamp, so you should be able to see its function quite well.

Hope that helps?

Good luck
/Peter

[Cooldeepseaaudio]

Thanks for your quick response, unfortunate that there isn't more info but it's definitely somewhere to start. there's a pair of the l150s and a ua741tc opamp on a board that appears to have been a modification to the original preamp circuit, the board is made more confusing by the lighter pcb using the darker pcbs ground as it's positive rail and both being powered from seperate power supplies. at least I have the two to test against each other, thanks!

[Peter BENSCH]

Good luck! However, you should also take a close look at the capacitors, especially the electrolytic capacitors, because after so many years they often dry out and become dead.

[Tesla DeLorean]

Something for a different era for sure. Not sure I've got databooks going back that far.

Yes, looks like the 16-pin DIP was replaced by new board. Best perhaps to reverse engineer the board, diagramming the connectivity on the other side with the componentry.

Documenting online, with the make/model of equipment, would allow it to be spidered and perhaps find other users, etc.

[Tesla DeLorean]

Some what of a goldmine here. One with some L1xx docs

https://www.rsp-italy.it/Electronics/Databooks/SGS/index.htm

https://www.rsp-italy.it/Electronics/Databooks/SGS/_contents/SGS%20Professional%20Semiconductor%202%20-%20Linear%20&%20Digital%20ICs%201973%201974.pdf

https://www.rsp-italy.it/Electronics/Databooks/SGS/_contents/SGS%20Linear%20Integrated%20Circuits%201981.pdf

SGS-Ates Data Book 1977/78 L150 "Expandor Circuit for Telecom"

http://www.bitsavers.org/components/sgs/_dataBooks/

Sure this isn't an LS150 ? https://datasheetspdf.com/datasheet/LS150.html

Applications in Cassette Tape Recorders and Intercoms

[Cooldeepseaaudio]

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@Tesla DeLorean wrote:

Some what of a goldmine here. One with some L1xx docs

https://www.rsp-italy.it/Electronics/Databooks/SGS/index.htm

https://www.rsp-italy.it/Electronics/Databooks/SGS/_contents/SGS%20Professional%20Semiconductor%202%20-%20Linear%20&%20Digital%20ICs%201973%201974.pdf

https://www.rsp-italy.it/Electronics/Databooks/SGS/_contents/SGS%20Linear%20Integrated%20Circuits%201981.pdf

SGS-Ates Data Book 1977/78 L150 "Expandor Circuit for Telecom"

http://www.bitsavers.org/components/sgs/_dataBooks/

Sure this isn't an LS150 ? https://datasheetspdf.com/datasheet/LS150.html

Applications in Cassette Tape Recorders and Intercoms

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This looks great, thanks so much for the info, will dig through and see if I can confirm which it is, 

Good idea to put the name on it, although the actual product seems as unknown as the IC,i it's an Emthree Hotline MN8 mixer/amplifier/echo unit, and I believe the echo unit which contains this board is identical to the Emthree computer echo.

[Tesla DeLorean]

Ok, so looks like it gets the echo via a "Tape Delay" spooling in the box top right of the equipment.

The L150 doesn't look to get many mentions, only in a Telecom context, and then there is documentation for an LS150 in a Telecom, and cassette tape context. Pin count also works.

If you look at the connectivity of the pins you can probably affirm or reject the possibility of this IC, based on signals, power, and filter components with respect to the pin wirings.

[Tesla DeLorean]

Of the pin headers, is one the Record Head, and the other the Playback Head for the magnetic tape?

Wonder how close the add-on board is to the expandor / compressor application circuits?

[Cooldeepseaaudio]

Long header on the right has 10v in on 1 pin, and the others are split between ground and the three playback heads, 4 pin header is the erase head power and I believe the record head, the add on board has a 2 pin behind the capacitors for AC Input,  21v or so i believe.