Lecson AC1 preamp - need a PCB layout - UK Vintage Radio Repair and Restoration Discussion Forum

yestertech · 18th Apr 2021, 8:36 pm

I'm currently working on one of these rather, how shall we put it, unconventional preamps !
I have some useful service information but I'm chasing down a fault with the FET switches of which there's quite a few !
Does anyone know where I might just find the PCB component layout details ?
Some lettering is visible on the board ( test points I think ) but most of it seems to have faded badly
THANKS

Andy

tony brady · 18th Apr 2021, 11:00 pm

I have the instruction manual and the circuit diagram but there is no pcb component layout.

if only on one input it looks like a case of tracing the signal from the input din sockets - didn't they have problems with the reed switches for input selection?

yestertech · 18th Apr 2021, 11:03 pm

Thanks Tony
That's probably the same info. I have, but alas no layout.
The reed switches are all operating but I need to check signal levels at specific take off/options points and the board is stuffed with transistors, dozens of which are FET switches.
It's a bit of a squash !

Andy

tony brady · 18th Apr 2021, 11:05 pm

I can imagine. happily I only had to fix a few of the power amps back in the day!

Craig Sawyers · 19th Apr 2021, 6:52 am

Lecson was the first company that Bob Stuart and Alan Boothroyd started up. They later started up, and ran, Meridian (originally called Boothroyd-Stuart Meridian).

There is a chance that, although both founders have retired, Meridian still have a service archive of Lecson.

And there is a company that specialises in fixing them up in York. They probably have service data http://www.lecson.com/

Good luck!

Craig

yestertech · 19th May 2021, 5:30 pm

I have now managed to fix the original problem with the FET switching on this, so this thread can be closed.

Andy

yestertech · 28th May 2021, 3:59 pm

as the thread is still open, I will 'bump' it as a new problem appeared and I now desperately need the PCB layout, annotated with component designations, as there are no markings on mine.
Or, would anyone have a unit which contains a PCB where these are present they could photograph for me ?

I'm happy to cover any reasonable expenses incurred.

Andy

18th Apr 2021, 8:36 pm	#1
yestertech Nonode Join Date: Dec 2002 Location: Coulsdon, Surrey, UK. Posts: 2,130	Lecson AC1 preamp - need a PCB layout I'm currently working on one of these rather, how shall we put it, unconventional preamps ! I have some useful service information but I'm chasing down a fault with the FET switches of which there's quite a few ! Does anyone know where I might just find the PCB component layout details ? Some lettering is visible on the board ( test points I think ) but most of it seems to have faded badly THANKS Andy

18th Apr 2021, 11:00 pm	#2
tony brady Hexode Join Date: Mar 2014 Location: Peacehaven, East Sussex, UK. Posts: 278	Re: Lecson AC1 preamp - need a PCB layout I have the instruction manual and the circuit diagram but there is no pcb component layout. if only on one input it looks like a case of tracing the signal from the input din sockets - didn't they have problems with the reed switches for input selection?

18th Apr 2021, 11:03 pm	#3
yestertech Nonode Join Date: Dec 2002 Location: Coulsdon, Surrey, UK. Posts: 2,130	Re: Lecson AC1 preamp - need a PCB layout Thanks Tony That's probably the same info. I have, but alas no layout. The reed switches are all operating but I need to check signal levels at specific take off/options points and the board is stuffed with transistors, dozens of which are FET switches. It's a bit of a squash ! Andy

18th Apr 2021, 11:05 pm	#4
tony brady Hexode Join Date: Mar 2014 Location: Peacehaven, East Sussex, UK. Posts: 278	Re: Lecson AC1 preamp - need a PCB layout I can imagine. happily I only had to fix a few of the power amps back in the day!

19th Apr 2021, 6:52 am	#5
Craig Sawyers Dekatron Join Date: Nov 2010 Location: Oxford, UK. Posts: 4,982	Re: Lecson AC1 preamp - need a PCB layout Lecson was the first company that Bob Stuart and Alan Boothroyd started up. They later started up, and ran, Meridian (originally called Boothroyd-Stuart Meridian). There is a chance that, although both founders have retired, Meridian still have a service archive of Lecson. And there is a company that specialises in fixing them up in York. They probably have service data http://www.lecson.com/ Good luck! Craig

19th May 2021, 5:30 pm	#6
yestertech Nonode Join Date: Dec 2002 Location: Coulsdon, Surrey, UK. Posts: 2,130	Re: Lecson AC1 preamp - need a PCB layout I have now managed to fix the original problem with the FET switching on this, so this thread can be closed. Andy

28th May 2021, 3:59 pm	#7
yestertech Nonode Join Date: Dec 2002 Location: Coulsdon, Surrey, UK. Posts: 2,130	Re: Lecson AC1 preamp - need a PCB layout as the thread is still open, I will 'bump' it as a new problem appeared and I now desperately need the PCB layout, annotated with component designations, as there are no markings on mine. Or, would anyone have a unit which contains a PCB where these are present they could photograph for me ? I'm happy to cover any reasonable expenses incurred. Andy