Lecson AP1 & AP2 Detailed Information

PMK145

Member
2016-12-27 5:05 pm
UK
As an opportunity to learn a bit more about amplifiers and particularly transistors, I've bought a Lecson AP2 Power Amp that has a circuit board that's been burned by overheating components - the centre of the board is all but trashed. I'm designing a new circuit board with as far as possible, the components, the layout and tracks being identical to the original. According to the schematic (not the one in the AC1/AP1 Service Manual the 'other one') there are a few resistor changes that distinguish the AP1 from the AP2, but even that schematic is a little different from the manufactured item.

Does anybody have a high def image of the AP1 that would enable the resistor values to be identified? I'm interested to see if my new boards would enable the repair of an AP1. The tantalum capacitors at the front end on mine are 15 microfarad not 22 microfarad. I wonder how many versions of the AP1 & AP2 were produced?

Attached are images of my 'good' board and the top silkscreen of my prototype replacement. I believe somebody had previously replaced two 0R27 wirewound resistors with that pole of grey resistors
 

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DavidN

Member
2009-01-17 2:01 pm
UK
Two-and-a-bit years later, I've come across your post. How did you get on? I have an AP1 apart (needed a big rubber mallet) with one burnt board. I might have to duck out of it.
 

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