Re: Broken Dell 1800FP Power Supply - when and when not to resolder?
I couldn't find the IC being sold anywhere other than Ebay, so took my chances and ordered a couple. It's coming from overseas so won't arrive for a while. In the mean time, I re-installed one of the ICs I had that doesn't show a short across pins 6 & 7 to test voltage across pins 6 & 7 when powered. Voltage measured in the milli-volts. Could some bad components upstream of the IC be causing this problem? I tested the small diode (D907) that's next to the IC off circuit; that tested fine. Also, I get around...
ptmy3
Member
Last Activity: 04-13-2017, 12:39 AM
Joined: 03-09-2016
Location: New York, NY
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Re: Broken Dell 1800FP Power Supply - when and when not to resolder?
They don't sell this IC anymore. Their websites just say product's obsolete. There are still some sellers on Ebay though. But given my past experience with buying this IC via Ebay, I'm a bit reluctant to do so again.Last edited by ptmy3; 03-23-2017, 09:53 AM.Leave a comment:
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Re: Broken Dell 1800FP Power Supply - when and when not to resolder?
I bought those 3 ICs from a random seller on Ebay. Do you have a recommendation of a reputable source?Leave a comment:
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Re: Broken Dell 1800FP Power Supply - when and when not to resolder?
I replaced all the capacitors in the power supply except for the large one. I'm still getting zero volts at the output terminals. Can anyone think of anything else I can try before I give up on this power supply?Leave a comment:
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Re: Broken Dell 1800FP Power Supply - when and when not to resolder?
I checked Q902. It wasn't shorted. Nest, I'll try replacing all the capacitors except for the big one. If that doesn't work, not sure what to do next other than to get a replacement power supply.Leave a comment:
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Re: Broken Dell 1800FP Power Supply - when and when not to resolder?
Yes, it measured 4.4 ohms off the board. That IC is new and has never been installed. Looks like I received defective merchandise. Hopefully, the other two are still good. Guess the only thing left for me to try is to replace the remaining capacitors. Anyone have another suggestion please post.Leave a comment:
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Re: Broken Dell 1800FP Power Supply - when and when not to resolder?
I looked over the document from the hyperlink posted by jiroy, but being an electronics neophyte, I wasn't able to get an useful information out of it to help diagnose my problem. Can someone more knowledgeable please help?Leave a comment:
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Re: Broken Dell 1800FP Power Supply - when and when not to resolder?
I soldered on a 47uf capacitor in place of the 33uf one for testing as you suggested. The output terminals still read zero volts. I measured resistance across pins 6 & 7 on the IC that's installed in the power supply again. I got 10.2 k-ohms if I put the red-color probe from the meter on pin 6 and black-color probe on pin 7. If I reverse the two probes, I got 4.2 k-ohms. I'm really confused. Why should reversing the meter probes make any difference when measuring resistance? I also measured the IC that I took...Last edited by ptmy3; 03-16-2017, 11:57 PM.Leave a comment:
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Re: Broken Dell 1800FP Power Supply - when and when not to resolder?
Yes, the big capacitor had very high voltage (over 150V if I recall). I took out the 50V 47uF capacitor to measure ESR. ESR was really high (measured around 42uF / ESR 7.5 ohms), so I replaced that with a 47uF 160V cap, which was the only 47uF I had on hand. Power supply still output zero volts. I took out the small 33uF/25V capacitor (C924 I think) to test. That also has high ESR with below-spec capacitance (measured 25uF / ESR 11.5 ohms). Unfortunately, I don't have a good 33uF capacitor lying around. I have...Last edited by ptmy3; 03-16-2017, 08:52 PM.Leave a comment:
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Re: Broken Dell 1800FP Power Supply - when and when not to resolder?
I know this is a really old thread, but I'm hoping someone knowledgeable is still looking at it once in awhile.
A few months ago, my 1800FP had no power when turned on. I repaired it by re-soldering D903 and D906, and replacing the ICE2AS01. Monitor worked great until yesterday when the problem returned - no power when turned on. I measured zero volts between both the 12V and 5V pins and ground on the output connector of the power supply. I thought I may have done a bad job with the soldering the first...Leave a comment:
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