Marantz 2275 rebuild

[bitomaxsp]

I am rebuilding my 2275. It was in a bit of tired shape i'd say. But when i disassembled it it was more that tired. I guess everyone is aware what is on the picture. I am make 3D model now to 3D print this lamp holder. Once i'll validate that model is ok in reality i'll make it public so everyone could print it. Mine is just melted over time and then it was cracked after bad LED conversion done by prev owner.



Also i am expecting quite a big order from mouser that should cover almost everything in the amp. More update will follow.

 

[bitomaxsp]

Here is how AMP looks now. I had to disassemble it almost completely to be able to conveniently replace things. Also my front panel needed some love.


My work place:

 

[Dingman]

I also have a 2275 in need of a refurbish, but I want to say...

Wow, you live on a volcano? IN the middle of nowhere?
Do you guys grow your own food?
How long does it take for Mouser parts delivery?

 

[JJCalvillo]

Wouldn't lay too much blame for the lamp housing damage on the previous owner. The housing was a bad choice of materials to hold lamps that get hot. Just replaced one on a 2250 that imploded in place.

 

[Steven Tate]

That is some serious disassembly there. It's going to be clean as a whistle when you get it all back together. Nice job!

 

[bitomaxsp]

Wouldn't lay too much blame for the lamp housing damage on the previous owner. The housing was a bad choice of materials to hold lamps that get hot. Just replaced one on a 2250 that imploded in place.

I agree about the material, but housing is just physically broken in several places.
At least i wouldn't tight metal to plastic like crazy

 

[JJCalvillo]

Here's the one I took outta the 2250. You don't have to tighten the screws much for the brittle plastic to crack. Often it's cracked with the original lamps in it, and the screws probably are in the same place the factory put them. The cracks and missing corner in the photo were there when I took the cover off.

 

[bitomaxsp]

Here's the one I took outta the 2250. You don't have to tighten the screws much for the brittle plastic to crack. Often it's cracked with the original lamps in it, and the screws probably are in the same place the factory put them. The cracks and missing corner in the photo were there when I took the cover off.
View attachment 2359150

Holy Christ! Mine is way way better. Why am I not satisfied?!. Anyway, i hope my model will help to maintain our AMP in good shape. Guy i am ordering 3D prints from broke his printer, so i have to wait.

 

[bitomaxsp]

While i was soldering back and forth components on P800 I noticed that traces are going to fall off the board. So here is my initiative project: P800 rebuild in Kicad. I'll make it BLACK Should be very in line with overall Marantz design.
Did some measurements already:

 

[bitomaxsp]

Initial design for P800. Polishing minor things

 

[bitomaxsp]

This is final and i am going to send it to production in a few days. Do not pay attention to wrong 3d models. They placed correctly but missing some pins Color will be black of course.

 

[bitomaxsp]

This is schematic i made for that PCB

 

[tonebells]

Look Great! I hope it works out well.

Tony

 

[dankik]

Awesome work. Was there a reason why you made a 3-layer board vs 1-layer? Did you print the lamp housing yet?

 

[bitomaxsp]

Awesome work. Was there a reason why you made a 3-layer board vs 1-layer? Did you print the lamp housing yet?

There no 3 layer boards. I made 2. Bottom is the ground, top - power.
Housing is printed, but i didn't get it yet. I'll post an update here once i get it;

Reason i rerout the P800 is that after soldering traces unglued. And I want black PCB - just esthetics (or my crazy with).

 

[bitomaxsp]

Starting to make a schematic for PE-01. I think it so much fun.

 

[bitomaxsp]

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):


Back (towards trans):

 

[bitomaxsp]

P800 arrived today.



Will start assembly tomorrow. Also i have 4 spare boards

 

[tonebells]

That looks great!

Tony

 

[bitomaxsp]

Along with P800 i also ordered a PCB for a device that allows to find band-end of the file capacitor (provided one has oscilloscope). I built it yesterday and use to find band end on those caps i ordered for P700 and PE01.
Here is how it works. Its build process and how it look inside. I am not the author. I just repeat what Mr.Carlson did in his video. It work awesome i must say.