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My try at a Really Nice Rebuild Marantz 2245 2270

patfont

patfont

AK Subscriber
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I have acquired a 2245 and plan on doing a rebuild on it. I will proceed in this order:

Power Supply Board
Main Filter Caps
Phono Board
Preamp Board
L/R Amp Boards

Will be replacing all e-caps and also the films, among other upgrades. Will try to keep tabs with pics and updates.
 
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Thoroughly enjoyed your other thread. I'll be watching with great interest! Thanks for sharing all this. Us newbies need all the examples we can get!
 
Mmm, nice parts goin' in this one. :thmbsp: 2245s are sweet when they're up to snuff.

If you really want to get fancy, you could match the KSC1845s that replace the 2SC458s in the phono section.
 
Jailtime said:
Mmm, nice parts goin' in this one. :thmbsp: 2245s are sweet when they're up to snuff.

If you really want to get fancy, you could match the KSC1845s that replace the 2SC458s in the phono section.
Click to expand...

Thanks, ordered 50 KSC1845's and will match a pair for Hfe, would like to get these exact!
 
patfont said:
Thanks, ordered 50 KSC1845's and will match a pair for Hfe, would like to get these exact!
Click to expand...

I've been waiting to see what your next project would be.

50 transistors is a good amount to match pairs with, you will probably find that they will divide themselves into two groups, of which every transistors in their group will be very close to each other.
 
The Power Supply caps are in and running and connecting a meter to J802 and J803 Voltage is set by trimmer R809 and holding a steady 35 on the button. The 2245 sounded pretty good the way it sat, but after the P/S caps were installed, things cleared up a bit and the sound had a more solid and authoritive feel to it.

Here are the caps in and running:



Just to be safe I draw a diagram of the board I am working on showing cap location and polarity, and triple check it. After each cap is soldered in also check for continuity. Also then use a dim bulb tester to power up just in case. If you do one board at a time and then check operation it is a lot easier to track down any problems.

Here is the tester I built:



Here is where I got the plans:


http://www.audiokarma.org/forums/showthread.php?t=465423
 
Next up will be the Main Filter Caps and changing them over to the screw terminal variety, along with a bypass cap.

Here is what is going in:

 
patfont said:
Next up will be the Main Filter Caps and changing them over to the screw terminal variety, along with a bypass cap.
Click to expand...

patfont, why did you decide on Chemicon caps for the main filters?
I thought you might have gone with Nichicon KG or Mundorf.
 
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I didn't do it on the 2245 I restored, but it wouldn't hurt to regrease that heatsinked tranistor. I'd replace the small transistors and diodes on P800 too. Just for kicks, really. :D
 
patfont, why did you decide on Chemicon caps for the main filters?
I thought you might have gone with Nichicon KG or Mundorf.

I had originally planned on using the KG's or Mundorfs. I spent very many hours planning what I would do with this 2245. As most of the work had already been done by other AK'ers, for example Catrafter with his phono board suggestions. As I was working on mocking up the Main Filters I do have the KG's in house but was very turned off by the installation aesthetics namely the blobs of solder I see on the wires wrapped around the small grounding rod, and how close that sits to the main filter caps especially the snap in type with the soldered on ring terminals. So I decided to go screw terminals. From the start I wanted this to be a "Really Nice Rebuild." My goals were superior sonics, and nice aesthetics, with components fitting and looking nice. If any one decides they would like to use the Chemi Main Filter caps I do not think they will disappoint you, I have seen them (the same series I used) used in $20,000.00+ amps by Lamm Industries a cutting edge company and others as well. If they are good enough for that I am sure they will do well in a 2245.


I didn't do it on the 2245 I restored, but it wouldn't hurt to regrease that heatsinked tranistor. I'd replace the small transistors and diodes on P800 too. Just for kicks, really.

They will get regreased along with the outputs thanks for the reminder. On to the P/S board are you talking about the relay driver transistors, and which diodes?


Ah I see a replacment relay, did you replace it in the new pic?

I did not, looks like the gentleman I bought it from had it done. It looks pristine and is working perfectly. When I am totally done I may go back in and replace it just so I can say I did.



And what do you use for bypass cap?

I decided on Vishay 730P 2uf.
I wanted this to be a reasonable rebuild that any one could do. I had to limit the cost of the films I was putting in. They had to sound excellent, and have a reasonable cost and fit nicely. (except one exception I made on the Phono and one on the Pre board)

Here are some of the films I auditioned to go in, just so you can get an idea, and none were crazy expensive.


 
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I look forward to seeing how the main filters look when you have the new caps installed.

I used the KGs in my 2245 but might go a different route with my 2270.
 
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Here is a pic of the Main Filter Caps that are coming out:

Up close you can see a bit of slight bulging on the bottom of the caps.





And here they are out:


 
patfont said:
On to the P/S board are you talking about the relay driver transistors, and which diodes?
Click to expand...

Yup, relay drivers. H804 and 807 are the diodes. The 2245 I restored had a hum that I could not track down, read an old thread here that the small transistors and diodes on the PS are problematic. Still haven't tried replacing them though.
 
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