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Marantz 2275 rebuild

Touch the cap and wait until device switches LED. When lowest amplitude is found that side is band end then just mark it.

Right LED (large amplitude)
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Left LED (lower amplitude) Band ed is on the left side.
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That i repeated for all films.
MKS (polyester) are not sensitive at all, i think it's du to production technology.

These are big 1uF MKP
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And these are MKS series:
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Band end usually goes to the lowest impedance part on schematic.
 
Now some words about P800 replica (not exact though) :)

First of all i checked it actually matches all other parts. It was a concern for me.
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As you can see match is perfect! I am super satisfied. And color matches Marantz style (+3dB to music power) :)

This is the original board. As you can see, 13V line takes it's voltage from Collector of H804. And there is a pad on the bottom that connects through the bolt to the tab of the transistor.
I didn't know how to make a footprint in KiCad like that — main reason i did it otherwise.

R815. In my design this resistor intentionally made larger (i mean footprint, same as R801 by the way) than others as it dissipates quite a lot of heat, hence brownish board.
That resistor must be installed on the long leads to allow better heat dissipation. (i'll show it later).
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This is quite it. Stay tuned and alive.
 

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Last edited:
Time for an update!

I finally had time to assemble LEDS completely! My STL model was printed and removed unnecessary parts, drilled additional holes (4 in total). I decided that it is easier to drill them, than print and i was right.
It fits absolutely perfect. Looks great. Attached is the ZIP with STL file that you can all use.
 

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bitomaxsp said:
While i am waiting for P800 PCB to arrive i am doing other PCBs :)
Since my amp (i think as many others) is only partially LED converted I decided to make proper LED conversion for indicators. This PCB is supposed to be direct replacement for original one.
There is a choice to have LED converted dial pointer (or leave it as lamp, less components to mount then).
This PCB is a bit longer (on the side) than original one. Following design is final. It would be green. Probably i'll have several not in use :)

Front (towards dials):
View attachment 2370525

Back (towards trans):
View attachment 2370527
Click to expand...

Regarding this proper LED conversion kit!
It looks good. Thought i figured that i did couple small mistakes.
1. I should have took SMD LEDS (but i ordered TH even before i decided to make this board). SMD will give better esthetic result since lighting will be more even.
2. Rect copper under the bolt heads should be round and bit bigger. This is fixed in Rev.B

I have 4 boards left of these.
 

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Nice work! May I make some suggestions? First you may want to spray paint the inside surfaces of your beautiful new lamp housing flat white to reflect light better. Secondly, and if you do redesign the function lamp board you may want to add a filter cap after each diode pack to reduce light flickering. Likely it would fit on the back of the board and be a tantalum type to fit. I use 68uF on my custom SMD warm white LED fuse lamps to do that along with a small bridge rectifier and it works great.
 
bitomaxsp said:
Time for an update!

I finally had time to assemble LEDS completely! My STL model was printed and removed unnecessary parts, drilled additional holes (4 in total). I decided that it is easier to drill them, than print and i was right.
It fits absolutely perfect. Looks great. Attached is the ZIP with STL file that you can all use.
Click to expand...

Where did you get the new lamp housing?
 
rBuckner said:
Nice work! May I make some suggestions? First you may want to spray paint the inside surfaces of your beautiful new lamp housing flat white to reflect light better. Secondly, and if you do redesign the function lamp board you may want to add a filter cap after each diode pack to reduce light flickering. Likely it would fit on the back of the board and be a tantalum type to fit. I use 68uF on my custom SMD warm white LED fuse lamps to do that along with a small bridge rectifier and it works great.
Click to expand...

i made tests on the bench before ordering the board. 100Hz flickering is not noticeable with LEDs. That is why i didn't add it.

Good point about paint. Unfortunately i had no choice about plastic, hence it's gray
 
Thanks for the quick reply! I'm confused. You've posted pictures of new, black P700 boards. So you have had these manufactured, yes? I'm just curious on the ball park cost. I need a few for different models, not the 2275.
 
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