Hi,

First post here. I'm rebuilding a power supply in a vintage synthesiser and the above part is discontinued. I'm just wondering if there are any substitutes.

Thanks,
Karl

 

Apologies. I can't seem to edit my original post. An alternative is the LM305N, which is also discontinued. Here is the schematic:

 

Apologies. I can't seem to edit my original post. An alternative is the LM305N, which is also discontinued. Here is the schematic:

There were probably functional equivalents from the likes of Unitrode and Raytheon etc, but a pin compatible drop in replacement isn't all that likely.

If the current is under 1A; you could replace the entire PSU circuit with 78xx and 79xx 3-terminal regulators.

If the current is more than 1A; you can consult the application notes for how to boost capability with external bypass transistors - the PSU shown in the schematic looks like it wouldn't need all that much track splicing to work those transistors into what's described in the appnote.

Accuracy should be fairly good, but if voltage balancing proves necessary - tie the wiper of a low resistance preset pot to 0V and the ground pins of the 3-terminal regulators to the ends of the track.

 

Hello,

Looking at the schematic, it seems to be used as a 10 Volts reference.
I can not make out the maximum current used.
You could probably use a LT1031 for this reference:
http://www.linear.com/product/LT1031

Bertus

 

Hey guys. Thanks for the replies. I'll be repopulating the existing PCB rather than making a new one so I'd need something to drop in, unfortunately.

I've found an analogue (LM305) online for a not too crazy price, so I may grab that.