Trevor White
Classic not Plastic
Hi All,
I purchased a new Luxman L-430 Duo Beta integrated amp in December 1984. At the time it was $859 Australian Dollars. Anyway, the unit has provided sterling service for the last 34 years, although for some 20 years in there it was only occasionally and lightly used.
Recently though, following the restoration of my Pioneer RT-707 RTR, I have had a lot more time on my hands and have been using the amp a lot. I listen to a very broad range of music at moderate volumes. The Luxman drives my modern KEF speakers very well, although the KEF's are a lot more efficient than my old West German WIGO 4 ways that I retired for the KEF's. So although the amp is probably not being driven really hard I was concerned about the state of the Electrolytic's in the machine.
So I decided to take the plunge and recap the amp, despite the fact that it was working perfectly. I have documented the process as I went along and thought I would post a thread with the details and pictures to possibly help others that may want to tackle their Luxman.
This is a LONG post, broken up into 4 sections.
First job is to remove the top cover and base. Followed by the front fascia. The covers are simple to remove being retained by obvious screws. The front fascia is retained by three screws along the top and two on the bottom. The control knobs are removed by pulling them off. It can take a good firm pull! I found the balance control to be quite stubborn. Be aware that the power transistors and the transformer are mounted very close to the base of the frame. I found it prudent to raise the unit up above my work table by sitting it on a couple of old BASF plastic tape boxes. This ensured the circuit boards, transistors etc were well clear of the table top.
You can also see that there are two cables with clip terminating plugs. These are attached to a pair of small circuit boards attached to the rear of the fascia plate. They are the Speaker selection and Recording mode LED connections.
Looking directly down on the L430 with all the original caps in situ.
Here is the left hand side of the main circuit board. You can clearly see the two big 15,000uF/63V Nichicon Filter Caps. Most of the caps on the board are Rubycon's, although in this shot you can see two red/brown caps near the centre that are actually Elna's labelled as 'For Audio'.
This is the right hand side of the main circuit board. Again most of the smaller caps are Rubycon's except for four dark blue caps at the top and bottom far right of the board. These are also Elna caps.
This is the Tone Control board. It mounts the Bass and Treble controls and implements the Luxman's turnover frequency shift tone controls. Most of the caps on this board are Mylar film type, although there is one small Electrolytic.
Here is the Volume control board. This also contains the Phono input pre-amp and switch for the MC Phono impedance selection. There are a large number of signal cables attached to this board via little wire clamp connectors.
This is the foil side of the main circuit boards. If you look carefully you can see that I have already removed the big filter caps, exposing the selection of mounting holes that Luxman have provided.
And this is the underside of the transformer and voltage selection board.
Here is a close up of the main filter cap mountings. Luxman have provided mountings that support 4 and 5 pin Filter caps. There are also two sets of holes which support the 40mm x 80mm with 25mm pin spacing and also smaller caps with 22mm pin spacing. A bit of forward thinking by Luxman there.
And here is the component side of the board with the Filter caps removed. The glue used to secure these is a bugger to remove! You can clearly see here the selection of mounting holes.
Here is a close up of the right channel power transistors. My intention was always to leave these alone as there is no evidence that they need maintenance. Therefore these circuit boards I left in situ mounted securely to the heat sink. There are caps on these boards to be replaced, but it is possible to access them in place.
And of course the left channel transistors.
This is the foil side of the circuit board that supports all the switches.
In order to work on the L430 it is necessary to partially remove the front panel that the tone controls, volume and balance control are mounted to. This is relatively straightforward with two screws at each side. There are also small screws that secure the two upper circuit boards that must be removed. Additionally you need to remove the nuts that secure the tone controls, balance control and volume control.
In order to get enough room to free the tone control board and the volume control board you need to unclip ALL of the wires that attach to the volume control board. Be careful here! Make sure you carefully label the cables and draw yourself a diagram that indicates which connector is which. Once the volume control board is no longer constrained by the wiring you will be able to pull the front panel outwards and lift the circuit boards up so that the foil side can be accessed. You don't need a lot of room here. NOTE: There is a strip cable that runs from the MC Impedance switch to the upper volume control board. I could not work out how to disconnect it and so was just VERY careful when lifting this board up and working on it.
Here is a bit more detail of the tone control board moved out of the way.
And the volume control board. Note the labels on all the wiring.
Here is the volume control board ready for it's recap. The Electrolytics are obvious but there are also two little Mica 33pF caps in the Phono section. It is a little brown lozenge near the bottom of the image.
Continued in Post #2
I purchased a new Luxman L-430 Duo Beta integrated amp in December 1984. At the time it was $859 Australian Dollars. Anyway, the unit has provided sterling service for the last 34 years, although for some 20 years in there it was only occasionally and lightly used.
Recently though, following the restoration of my Pioneer RT-707 RTR, I have had a lot more time on my hands and have been using the amp a lot. I listen to a very broad range of music at moderate volumes. The Luxman drives my modern KEF speakers very well, although the KEF's are a lot more efficient than my old West German WIGO 4 ways that I retired for the KEF's. So although the amp is probably not being driven really hard I was concerned about the state of the Electrolytic's in the machine.
So I decided to take the plunge and recap the amp, despite the fact that it was working perfectly. I have documented the process as I went along and thought I would post a thread with the details and pictures to possibly help others that may want to tackle their Luxman.
This is a LONG post, broken up into 4 sections.
First job is to remove the top cover and base. Followed by the front fascia. The covers are simple to remove being retained by obvious screws. The front fascia is retained by three screws along the top and two on the bottom. The control knobs are removed by pulling them off. It can take a good firm pull! I found the balance control to be quite stubborn. Be aware that the power transistors and the transformer are mounted very close to the base of the frame. I found it prudent to raise the unit up above my work table by sitting it on a couple of old BASF plastic tape boxes. This ensured the circuit boards, transistors etc were well clear of the table top.
You can also see that there are two cables with clip terminating plugs. These are attached to a pair of small circuit boards attached to the rear of the fascia plate. They are the Speaker selection and Recording mode LED connections.
Looking directly down on the L430 with all the original caps in situ.
Here is the left hand side of the main circuit board. You can clearly see the two big 15,000uF/63V Nichicon Filter Caps. Most of the caps on the board are Rubycon's, although in this shot you can see two red/brown caps near the centre that are actually Elna's labelled as 'For Audio'.
This is the right hand side of the main circuit board. Again most of the smaller caps are Rubycon's except for four dark blue caps at the top and bottom far right of the board. These are also Elna caps.
This is the Tone Control board. It mounts the Bass and Treble controls and implements the Luxman's turnover frequency shift tone controls. Most of the caps on this board are Mylar film type, although there is one small Electrolytic.
Here is the Volume control board. This also contains the Phono input pre-amp and switch for the MC Phono impedance selection. There are a large number of signal cables attached to this board via little wire clamp connectors.
This is the foil side of the main circuit boards. If you look carefully you can see that I have already removed the big filter caps, exposing the selection of mounting holes that Luxman have provided.
And this is the underside of the transformer and voltage selection board.
Here is a close up of the main filter cap mountings. Luxman have provided mountings that support 4 and 5 pin Filter caps. There are also two sets of holes which support the 40mm x 80mm with 25mm pin spacing and also smaller caps with 22mm pin spacing. A bit of forward thinking by Luxman there.
And here is the component side of the board with the Filter caps removed. The glue used to secure these is a bugger to remove! You can clearly see here the selection of mounting holes.
Here is a close up of the right channel power transistors. My intention was always to leave these alone as there is no evidence that they need maintenance. Therefore these circuit boards I left in situ mounted securely to the heat sink. There are caps on these boards to be replaced, but it is possible to access them in place.
And of course the left channel transistors.
This is the foil side of the circuit board that supports all the switches.
In order to work on the L430 it is necessary to partially remove the front panel that the tone controls, volume and balance control are mounted to. This is relatively straightforward with two screws at each side. There are also small screws that secure the two upper circuit boards that must be removed. Additionally you need to remove the nuts that secure the tone controls, balance control and volume control.
In order to get enough room to free the tone control board and the volume control board you need to unclip ALL of the wires that attach to the volume control board. Be careful here! Make sure you carefully label the cables and draw yourself a diagram that indicates which connector is which. Once the volume control board is no longer constrained by the wiring you will be able to pull the front panel outwards and lift the circuit boards up so that the foil side can be accessed. You don't need a lot of room here. NOTE: There is a strip cable that runs from the MC Impedance switch to the upper volume control board. I could not work out how to disconnect it and so was just VERY careful when lifting this board up and working on it.
Here is a bit more detail of the tone control board moved out of the way.
And the volume control board. Note the labels on all the wiring.
Here is the volume control board ready for it's recap. The Electrolytics are obvious but there are also two little Mica 33pF caps in the Phono section. It is a little brown lozenge near the bottom of the image.
Continued in Post #2
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