Naomi PSU recap map

ahcmetal

Super Spy Agent
10 Year Member
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Aug 25, 2010
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20180219_185405.jpg

So...I removed this resistor from the board, looked up the color code and as best I could guess from the faded colors...its a 69ohm one. I put the meter on it and the meter read 68ohm, so I'm leaning toward ordering that value...

I do believe it's a "Metal Film" type resistor, so upon entering this into DigiKey...I have 187 results...anybody have any opinions on what exactly a good replacement would be??

https://www.digikey.com/products/en...14&quantity=0&ColumnSort=0&page=1&pageSize=25

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I bought a NNC cab a few weeks back and recently disassembled it for a little refurb...

The PSU currently works, but it was quite dirty and noisy. I opened it up to clean it and noticed the back of the pcb looks like it's taken a lot of heat...

20180216_205402.jpg

On the opposite side of the heat mark are these caps and resistors...

20180216_204952.jpg

The case fan is mostly shot, the cap on the right is bulging on the top, there's some green corrosion (possibly from a nearby leaky cap??) on one of the resistor legs, a second resistor looks to have a black colored leg and the cap on the left has the outer casing flaking off.

Everything else on the PSU looks normal visually except in this area...

What do you guys think? Replace all the caps on the board or just the ones in this area? Replace all the resistors or just the two that looked bad??

**UPDATE**

I replaced all the components and put together a list in case anybody else needs it in the future for reference:

20180310_151557.jpg
20180219_140602newnetcity.png
 
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Heinz

Parteizeit
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Feb 13, 2005
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I'd remove all the caps and those large power resistors then scrub the fuck out of it with simple green or equivalent non-phosphorus cleaner and take the hose to it. Heat your oven to 150C (300F) switch it off and then place the PCB inside for a few hours. Solder in new components and laugh about your success.
 
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ahcmetal

Super Spy Agent
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Sounds like a plan...I'll head over to digikey and see what's available!
 

ahcmetal

Super Spy Agent
10 Year Member
Joined
Aug 25, 2010
Posts
624
Anybody know their way around resistor ordering on digikey? Lots of options over there...
 

GohanX

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Heinz

Parteizeit
15 Year Member
Joined
Feb 13, 2005
Posts
22,289
Resistors will have a 1%,5% or 10% -/+ on their stated value depending on the resistor technology. Looks like a metal film but you can go metal oxide as they have a tighter tolerance, make sure you pick the same wattage or higher and you can measure the dimensions of the old ones to get a good idea on what it is.

I had to replace some resistors on a nanao chassis recently and yeah I had the same confusion, too many choices. Just pick the value, wattage and technology and you shouldn't have too many options. Stay away from carbon film!
 
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