Farnell L30 PSU - UK Vintage Radio Repair and Restoration Discussion Forum

super_7b · 12th Jun 2011, 3:50 pm

Hi,

I have one of these PSUs and it isn't performing quite right. Having had a look inside, I'm not surprised, as the caps and resistors look original and it appears to be late 1960's or very early 1970's (all the transistors are OCxx series).

I am going to replace the electrolytics and any off-value resistors, but I would like to know how to set it up properly. Has anybody got a circuit diagram, or better yet, a full manual for one of these? The one I found on this site relates to a "newer" (relatively) model with 2N transistors.

BR

Mick

Stockden · 12th Jun 2011, 9:00 pm

Hello Mick,

This manual shows OC type transistors in the circuit. With luck it's the one you need.

Hugh

super_7b · 13th Jun 2011, 7:20 pm

Thanks a load Hugh,

What a star! Exactly the model I have, an L30.

Having opened it up for a fuller inspection, it has been "repaired" by someone with what looks a hot poker at some time and a transistor had been replaced. In doing so, a couple of mounting lands have lifted and one had parted company with the track on the board. I think this is why it wasn't working correctly.

I will replace all the electrolytics while it is apart as they are dated Nov 1963 to Mar 1964. I am impressed they have held up for so long.

BR

Mick

12th Jun 2011, 3:50 pm	#1
super_7b Retired Dormant Member Join Date: Dec 2010 Location: Wakefield, West Yorkshire, UK. Posts: 2	Farnell L30 PSU Hi, I have one of these PSUs and it isn't performing quite right. Having had a look inside, I'm not surprised, as the caps and resistors look original and it appears to be late 1960's or very early 1970's (all the transistors are OCxx series). I am going to replace the electrolytics and any off-value resistors, but I would like to know how to set it up properly. Has anybody got a circuit diagram, or better yet, a full manual for one of these? The one I found on this site relates to a "newer" (relatively) model with 2N transistors. BR Mick

13th Jun 2011, 7:20 pm	#3
super_7b Retired Dormant Member Join Date: Dec 2010 Location: Wakefield, West Yorkshire, UK. Posts: 2	Re: Farnell L30 PSU Thanks a load Hugh, What a star! Exactly the model I have, an L30. Having opened it up for a fuller inspection, it has been "repaired" by someone with what looks a hot poker at some time and a transistor had been replaced. In doing so, a couple of mounting lands have lifted and one had parted company with the track on the board. I think this is why it wasn't working correctly. I will replace all the electrolytics while it is apart as they are dated Nov 1963 to Mar 1964. I am impressed they have held up for so long. BR Mick