Saved proprietary Macron MPT-350D
Okay, so this is another one of the last projects I did at my last company. Thing got about 39,000 running hours on it. The customer brought this computer in and wanted general diagnostics run, even though everything was "fine." I was immediately interested by the chassis ( http://www.newegg.com/Product/Produc...82E16811119071 ) and once I looked at the back of the power supply I yelled "MACRON" I noticed that it was indeed a Macron once I looked at the label, and that it wasn't quite an ATX PSU....I immediately knew that the PSU had bad caps (I even bet my coworker $1000 on it, he did not accept. DAMN! ) but the computer already had a memtest running on it. I opened the top case, and WOW, the thing was fucking hot! Just the side chassis of the PSU was 42C! I guessed that it was powering a Prescott P4 because just by glancing at the board I knew it didn't support Core 2, and the early 2005 sticker on it suggested it wasn't a Pentium D. Once the memtest was done I powered it down and took the PSU out. The thing had been off for about a total of 6 minutes, and the secondary heatsink still measured 75C! The primary was about 50C. I let it cool down and took the heatsink off the CPU. It was indeed a Prescott 3.2GHz P4, 640 model. The thermal paste was so dry and got so hot that it actually started turning brown. The unit was also powering a single 7200RPM hard drive, one DVD drive, a Radeon X1650, 4 1GB DDR modules, two TV tuner cards, a wireless G PCI card, a PCI sound card, and two 0.30A exhaust fans running at full speed. After looking at the inside of the PSU only having a 16A ultra fast, I'm utterly amazed that the thing didn't blow up! And look how cooked that resistor got. I couldn't see the value so I decided not to replace it.
When pulling the secondary heatsink to replace the 16A ultra fast with a 30A schottky, the 16A rectifier partially split down the middle in the space where the three leads go in to the silicon, and you can see how the heat discolored it. The thing is a true champ Most of the rectifier screws were becoming loose so I tightened them.
Almost all of the caps tested bad. The only caps that didn't test bad were both 2200uF 6.3V G-Luxon LZ caps on the 3.3V rail (I don't know how this is possible) and the 1uF 50V caps on the secondary. The 10uF 50V GoldLink caps on the BJT circuit read ~2.5uF and over 40Ω ESR I replaced all of the caps with Japanese parts, and because of the high heat and running hours, I replaced the 1000uF G-Luxon caps on the input with barely used 820uF Asia'X. I also redid a lot of the soldering joints that looked like they got weak from the heat they endured.
The Superred fan span okay, but they covered the bearing so that I couldn't get to it. Because of this, I didn't take the risk and just replaced it with a Power Logic ball bearing fan Because of the ripple that the hard drive endured, I talked the customer into cloning their drive to a brand new 500GB one. Everything went successful. I only had an hour to work on this thing, so those are the things I did to it. But afterwards, the thing ran so much cooler! The side chassis of the PSU was barely lukewarm, and the air coming out of the back of the PSU was just warm instead of hot. Just another example of how tough these old Macron PSUs are. I don't think the customer realized what had to happen for their precious computer to maintain proper operation, but I sure felt good after the project was done.
Okay, so this is another one of the last projects I did at my last company. Thing got about 39,000 running hours on it. The customer brought this computer in and wanted general diagnostics run, even though everything was "fine." I was immediately interested by the chassis ( http://www.newegg.com/Product/Produc...82E16811119071 ) and once I looked at the back of the power supply I yelled "MACRON" I noticed that it was indeed a Macron once I looked at the label, and that it wasn't quite an ATX PSU....I immediately knew that the PSU had bad caps (I even bet my coworker $1000 on it, he did not accept. DAMN! ) but the computer already had a memtest running on it. I opened the top case, and WOW, the thing was fucking hot! Just the side chassis of the PSU was 42C! I guessed that it was powering a Prescott P4 because just by glancing at the board I knew it didn't support Core 2, and the early 2005 sticker on it suggested it wasn't a Pentium D. Once the memtest was done I powered it down and took the PSU out. The thing had been off for about a total of 6 minutes, and the secondary heatsink still measured 75C! The primary was about 50C. I let it cool down and took the heatsink off the CPU. It was indeed a Prescott 3.2GHz P4, 640 model. The thermal paste was so dry and got so hot that it actually started turning brown. The unit was also powering a single 7200RPM hard drive, one DVD drive, a Radeon X1650, 4 1GB DDR modules, two TV tuner cards, a wireless G PCI card, a PCI sound card, and two 0.30A exhaust fans running at full speed. After looking at the inside of the PSU only having a 16A ultra fast, I'm utterly amazed that the thing didn't blow up! And look how cooked that resistor got. I couldn't see the value so I decided not to replace it.
When pulling the secondary heatsink to replace the 16A ultra fast with a 30A schottky, the 16A rectifier partially split down the middle in the space where the three leads go in to the silicon, and you can see how the heat discolored it. The thing is a true champ Most of the rectifier screws were becoming loose so I tightened them.
Almost all of the caps tested bad. The only caps that didn't test bad were both 2200uF 6.3V G-Luxon LZ caps on the 3.3V rail (I don't know how this is possible) and the 1uF 50V caps on the secondary. The 10uF 50V GoldLink caps on the BJT circuit read ~2.5uF and over 40Ω ESR I replaced all of the caps with Japanese parts, and because of the high heat and running hours, I replaced the 1000uF G-Luxon caps on the input with barely used 820uF Asia'X. I also redid a lot of the soldering joints that looked like they got weak from the heat they endured.
The Superred fan span okay, but they covered the bearing so that I couldn't get to it. Because of this, I didn't take the risk and just replaced it with a Power Logic ball bearing fan Because of the ripple that the hard drive endured, I talked the customer into cloning their drive to a brand new 500GB one. Everything went successful. I only had an hour to work on this thing, so those are the things I did to it. But afterwards, the thing ran so much cooler! The side chassis of the PSU was barely lukewarm, and the air coming out of the back of the PSU was just warm instead of hot. Just another example of how tough these old Macron PSUs are. I don't think the customer realized what had to happen for their precious computer to maintain proper operation, but I sure felt good after the project was done.
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