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Marantz 2245/2270 P750 Amp Board Replica

These boards are single sided PCBs. Maybe they had some metal eyelets like the below?

F1603335-01.jpg
 
Almost finished :banana:. I had forgotten how slow it was to import the vector dwg files in the pcb editor, because all of the curves, arcs etc... They are almost twice more than on the previous PCB. And the computer is still the same... 16GB RAM wasn't enough. Аfter 2 hours unsuccessful attempts to import the copper layer - the most complicated one, I gave it up... Later decided to try "divide and conquer" strategy. Why to import all of them traces all at once? Tried only by few and it worked! It took me about 6 hours, but the job is finally done! Here is how it should look after the fabrication with green and red mask applied, compared next to the Mikes's board scan:
top.JPG green.JPG
red.JPG P750_scan_bottom.jpg
 
Wow - that's so purrfect. Eagerly waiting to see how the real boards will look.
Is the mounting hole for the toroid a bit smaller?
 
The hole for L751 is 3.2mm, assuming they use 3mm screw for the coil, it should be enough. The drill file will be the last exported. I wanted to compare the hole and slot sizes with the original board, but there is still no delivery. I'll wait a little longer, it's a busy period for the post offices now...So except the drill file, all gerber files for the other layers are ready for sending to PCB factory. And just for complicating the task, I added an extra layer - top solder mask with the copper pattern. I've seen this in some vintage Marantz PCB designs... I think it looks cool. What do you say, should it stay or not?
top solder.JPG
 
The board didn't make it.. I've been distracted by the fires here and now the rain. I'll get it out this week now the fires are out and the rain is gone
 
Mike Sweeney said:
The board didn't make it.. I've been distracted by the fires here and now the rain. I'll get it out this week now the fires are out and the rain is gone
Click to expand...
Glad that everything is back to normal, Mike. Actually no need to send the board, your scans did a great help. I already compared the holes with the Marantz 1060's and placed an order for a few boards. We'll see what will come out...
Now it's time to start working with the newer revision version...
 
I redrawed the fully matching schematic for this newer revision PCB and decided to attach it here in hi resolution PDF format for downloading, if somebody is interested. Parts list replaced with currently available where possible...
Here is also the picture, hope I don't have mistakes:
schematic.JPGschematic_org.JPG
 

Attachments

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:confused: Actually, I made a huge mistake! After starting to work and collect info for the "newer" revision PCB, It appears that the PCB and schematic I've done so far IS ACTUALLY THE NEWER REVISION! So the PCB and the schematic above this post are all applied to the Marantz 2270 with S/N above 3901 and Marantz 2245 with S/N above 3301. I'm sorry for the confusion. I'll check if it's possible to edit my previous posts with the correct info...
 
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Not to add to the workload you already have, but I thought about the fact that so many Marantz receivers and integrated amps share the same phono board. This would be a board that would be in high demand. I have a 2245 with a patched up board I would love to replace. So....if you complete your 2270 work (fantastic job!), take a breather and look for another project - consider the ubiquitous Marantz phono board. :D
 
What could possibly go wrong with that PCB? :D Is it prone to burn or brake somewhere or what? But why not? Considering the lack of info for the earlier revision P750 PCB, maybe this could be my next small winter project. Plus I have a 2230 with the same board to use as a reference. A quick check shows they use it also in 2245, 2270, 2330, 2325, 2285... It's different in 1060 though...
 
I seem to see a lot of posts with problems with that board. Most probably are not physical board problems, but some of them are. In my case, I got one that had been butchered by someone - several broken traces and burned solder pads. I got it working, but it’s ugly and I worry about longevity.
 
Steven Tate said:
I seem to see a lot of posts with problems with that board. Most probably are not physical board problems, but some of them are. In my case, I got one that had been butchered by someone - several broken traces and burned solder pads. I got it working, but it’s ugly and I worry about longevity.
Click to expand...

I don’t really have enough hours on it to say I’m trouble free yet. Also, I’m still rebuilding the P-700 boards so I’m playing pre outs through an external McIntosh amp. At this point, no issues, sounds great and an easy install. Also, my soldering/ desildering skills seem to be improving. I have to say, I trashed a couple of boards, mainly desoldering, during my first couple of rebuilds. Self imposed issues.
 
I'm planning to place an order for a few of those... I found more quicker and efficient way to import vector drawings in PCB editor (without upgrading my computer yet) :). Also the drawing of the traces is much more easy with the graphic tablet now... So I wanted to practice the technique. I hope to find another interesting board to make before I forget all the steps needed...:beerchug:
 
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Some minor corrections on the silkscreen, added top mask... I kind of prefer the red color for some reason. So this should be the final version of the phono pcb, let me know if any errors noticed. Received an email from the PCB factory, P750 amp board is on the way, maybe it will arrive by the end of this year, but I doubt it... And the tone board maybe is the best candidate for the next reproduction project.
phono_top_final.JPGphono_bottom_final.JPG
 
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