Dead P4P800 Desktop Repair
Often when I want to check if my USB bootable memory sticks work I test them on my older P4P800 desktop computer. This way avoiding the risk in damaging the bootsystem on my newer computers. But this time my old trusted Asus computer refused to start up. And nothing worked, not even the Num lock led on the keyboard. Which always is a good indicator.
After a quick look on the component side of the mainboard I immediately noticed one larger bulged e-cap. Here marked in the photo with the purple arrow. Removing it was easy with using my Ersa MS6000 solder station by melting the solder on the solder side and at the same time carefully bit by bit pulling the legs of the e-cap out the very narrow tin filled holes.
As in these cases it is impossible to do it any better other ways. This way keeping tracks and through hole via’s intact. It was a 1500uF 6.3V e-cap. These are mostly special low ESR type of capacitors. Below the now removed bad e-cap.
I tried to open the holes after the e-cap was removed to make it free for a new capacitor but it was very hard and I probably could have done it by using my hot air gun to provide heat on the component side and at the same time suck out the tin on the solder side. But there was no need to risk damaging the tracks or the mainboard because 2 of those small 1000uF 6.3V e-caps in parallel would easily fit under the mainboard on the solder side without sticking out too far at all.
Previous photo now shows the open spot where previously the bulged e-cap was soldered.
And above photo shows the new mounted e-caps that also were glued to each other and to the solder side to give them some extra mechanical strength and some extra electrical insulation.
They were very small and really did easily fit under the mainboard even without ever touching the metal outside plate. And I had enough of those in stock for future Mainboard repairs. But of course I first checked if my Asus P4P800 desktop booted again and it worked like a new computer again!
This Rev.2.0 mainboard may be rather old now but it is still a perfectly good computer to copy a cd or dvd, read a memory stick or to test the boot system of any media. And it has a perfect speed controllable Zalman cooler fan, IDE ports, and 2 Sata ports. And a good old 3.5 inch floppy drive and a card reader. With a removable harddisk in bracket plus selectable system boot harddisks. Furthermore it has a special Nvidia card with remote media controller to play videos with it.
And after both new e-caps were added everything worked again like it always did! Next photo shows one of both boot systems.
Albert van Bemmelen, Weert, The Netherlands
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Note: You can read his previous repair article in the below link:
https://jestineyong.com/tv-ir-remote-that-eats-lithium-batteries-fixed/
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Parasuraman S
March 23, 2021 at 8:53 pm
Very glad to read your article after a gap! Nice fix!
Albert van Bemmelen
March 23, 2021 at 11:07 pm
I was very happy it was not any hard to fix defect. And this way it was easily fixed and I didn't need to disassemble the entire computer with all cables and devices still attached to it, just to be able to remove the mainboard for desoldering and replacing a new capacitor on the component side. By placing the new e-caps on the solder side of the board they were still easily replaceable in the event they would still fail again any next time. Any disassembling of the computer this way was not at all necessary!
By-the-way: The article gap was only how it looks because this repair and my previous article were practically sent in at the same time. I'm sure I left more gaps inbetween previous repairs too. Mainly because of having less time to fix defect devices these days. (Because I also work 5 days a week, since over a year now, as a postman delivering mail by bike which is a rather physical job).
Amir
March 23, 2021 at 11:28 pm
Good article and nice repair.
Anwar Shiekh
March 24, 2021 at 1:34 am
I prefer the fix to look very much like the original. I tend to hold the soldering iron on the hole as I prepare to blow from the other side as I remove the solder iron. Other than that there are some very cheap desoldering irons
Albert van Bemmelen
March 24, 2021 at 1:45 pm
Yes agreed, I do too Anwar. But I didn't want to damage any component or any of the wiring with my hot air station, and removing the mainboard this way was not needed and made the repair fast, safe, and easy. Also in case these e-caps fail again a next time.
Ken
March 24, 2021 at 4:55 am
One trick I’ve used to open the holes of a removed component is to run a toothpick through the melted solder and the hole will remain clear for new leads to be inserted and will not stick to the wood.
Albert van Bemmelen
March 24, 2021 at 1:40 pm
That probably wouldn't work in this case Ken because the holes were really thin! With the risk it also would result in wooden broken off parts of material inside the holes. And trying to remove that would be close to impossible! I had special thin hard metal tools bought for these kind of repairs but even those wouldn't go into those tiny holes!
And I could have used my hot air station on the component side while using a tinsucker on the solderside. But that would require me to disassemble the mainboard to make sure none of the wires or other parts would be damaged by the hot air iron. But as said this was so much easier and also a fine way in case the e-caps had to be replaced again.
Anwar Y Shiekh
March 24, 2021 at 10:07 am
A stainless steel needle is also good for clearing holes as the solder will not stick to stainless even with flux around.
Albert van Bemmelen
March 24, 2021 at 1:49 pm
I have in the past bought those specially for these kind of repairs, but as said they also didn't fit through the holes without the risk of damaging the tracks or the through hole vias!
Yogesh Panchal
March 24, 2021 at 4:01 pm
Albert,
Good attempt!use Good quality Flux and De-soldering wick or using Blunt syringe needle also good idea. I made for me using hand sewing steel needle ( I made 3 with different thickness of needles ) by providing proper finger grip using small Ball pen plastic Cap filled with M-Seal Regular Epoxy Compound Adhesive Putty in it.
Albert van Bemmelen
March 24, 2021 at 7:20 pm
Yes if you have those made very thin needles you could try to pick open the vias. With the risk damaging the through hole vias or the tracks to them. But there was no need at all to place the replacement capacitor on the component side again. Placing two of them was easy and got the computer running again just fine! And this way I didn't have to disassemble the computer mainboard, remove any wiring or connected device either. And everything was up and running within minutes!
Lee
March 25, 2021 at 1:37 pm
I have repaired Motherboards using all the techniques stated over years. Getting that solder out of the holes is a real pain.
Albert van Bemmelen
March 25, 2021 at 7:24 pm
I completely agree Lee! They don't make it any easier these days! Like the many bga mounted chip problems that require hotfixing or completely replacing bad GPU or other mainboard controller chips. Which require new tools, new techniques and much time to fix the problem. Luckily there was no need here to mount the replacement e-cap(s) on the component side again because there was plenty of space on the solderside anyhow. And the result was the same and the repair much quicker!
Lynn Blakely
March 26, 2021 at 4:37 am
Albert: You made the best choice, the easiest, and the fastest. After all we may want to make it look original, but sometimes that is not practical, to result in taking too much of a risk, as you have already said.
Albert van Bemmelen
March 27, 2021 at 11:04 pm
You summarize exactly what I was trying to say Lynn. Thanks for your appreciated reply!
ivan1
March 27, 2021 at 10:04 am
HOLA a todos mi solución casi infalible ,uso agujas hipodérmicas las cuales redondeo ligeramente su punta ,para evitar que se doble ,al ejercer presión sobre ellas girándolas para que no se peguen ,mientras caliento por el otro lado con la punta del cautín ,las hay de muchos diámetros y se pueden usar muchas veces por ser inoxidables ,claro que las vende con las jeringas ,estas las uso para limpiar con alcohol isopropílico secciones estrechas en los circuitos evitando usar solventes es spray
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HELLO everyone, my almost infallible solution, I use hypodermic needles which I slightly round their tips, to prevent them from bending, by exerting pressure on them by turning them so they do not stick, while I heat on the other side with the tip of the soldering iron, there They have many diameters and can be used many times because they are stainless, of course they are sold with the syringes, I use them to clean narrow sections in the circuits with isopropyl alcohol avoiding the use of solvents is spray
Albert van Bemmelen
March 27, 2021 at 7:00 pm
Thanks ivan1. If we only would have the smallest needles available that could make a difference. Sadly the only hypodermic needles I have are those that were bought as replacement ink sets to inject new ink into my old HP printer cartridges. But they are still too thick to be of any use here. And I have completely taken apart those old now obsolete HP (710 color, 840C) printers for spare parts. My secondhand Brother DCP-385C deskjet printers are so much more trustworthy and cheaper in use of ink and never disappoint! (and this Brother printer always needs live 230VAC input power to control and clean the ink channels to prevent them from drying out!, which never was any good on HP or Epson printers!)
Humberto
April 2, 2021 at 12:07 am
Wow! Albert an old MotherBoard, I had not seen one, years ago.