The ever-cheerful Martin called ...
"I'm chuffed with the R-1040 you did, can you do my other one?"
Yeah ... why not.
.. and he brings me another R-1040 to do, and also a rather nice L-80V (which was unexpected, as somewhere our wires had got crossed!)
Luxman do make some nice looking kit.
Anyway , off with the wooden sleeve (in the same manner as the R-1040) and I'm greeted with a very familiar sight...
... it's the same as the L&G L2800 I did here all those years ago, or at least the main PCB is.
It's also suffering with the same leakage... Let's get re-capping the thing.
Almost as much of a slog as the R1040....
Much in the same way as the L&G 2800, output transistors are a mix of manufacturers, this time on the same channels!
To get at the capacitors on the tone control and loudness control boards, first remove the knobs..
located on the top and bottom of the front panel.
... undo the securing nuts holding the two tone control pots to the front panel.
... and, whilst access is still limited, you can now get at the caps on the tone control board
Similar process with the loudness board. Remove the four securing screws...
... and re-cap the board.
The main smoothing caps, whilst looking in good condition, are both reading low in value. This is probably the cause of the hum. Sadly the caps I used in Martin's R-1040 are now on a long back-order time. Some other Nichicon caps are in stock, so these are ordered, but are of smaller diameter than the originals, so some sleeves are 3D printed, and the caps replaced. I've printed four, because I'm going to need 4 for Martin's other R-1040
Snug...
With the re-cap complete, the bias is set, and the amplifier is a stunning performer.
It's given a good soak test with the most excellent International Teachers of Pop
Now to do Martin's other R-1040 !
No comments:
Post a Comment