Re: Apple power supply A1098
I see it has been a year and a bit since anyone comment on this; was the original powersupply every fixed? Did a correct schematic turn up? I ask as I am in the process of trying to repair one of these power supplies myself. Any updates would be appreciated.
acornish
Member
Last Activity: 01-14-2022, 04:19 PM
Joined: 04-22-2015
Location: Edmonton, Alberta
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Re: Wine Fridge Power Board
True enough and as the forum's name suggests that sure could be the problem. I will replace them next week and see what happens.
Any thoughts about my Transformer 1 concern?
acornish...Leave a comment:
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Re: Wine Fridge Power Board
keeney123, Yikes! That paint sounds like quite a challenge. I have painted before around the house but it usually dries in an hour or so. It is pretty dry where I live and I am sure that makes a difference, but it also sounds like your paint might be a bit watered down. You mention using a "brush", might a roller have helped? That is what I usually do, only using a brush to "cut in" the edges. I have been lucky enough to get some good advice from the painters here on our campus it sure has helped the projects at home....Leave a comment:
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Re: Wine Fridge Power Board
budm, the capacitance of C16 is 0.97 uF, and it is rated at 1.0uF
The other large capacitors on the board:
C20 = 0.070 uF, rated at 0.1 uF (capacitor near fuse)
C15 = 118 uF (rated 120)
C12 = 123 uF (rated 120). These are the units mentioned by kenny123 and are "near" C16.
These caps have not been replaced, but appear to be "close" to their rated values. Is "close" good enough, or should they be exact.
When I start looking at voltages, the whole system...Leave a comment:
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Re: Wine Fridge Power Board
keeney123
Wow! Thanks for doing so much work on this. I have also been busy at the University I work at and have not had a chance to do anything with this. I will check out the capacitors and work through you schematic in post #85. I really appreciate the time you have put in to this for me-"Thank you" just seems inadequate.
I will post back as soon as I can.
I hope the move and the painting are going well. I have done similar work at home recently myself and although gratifying when finished, it is a...Leave a comment:
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Re: Wine Fridge Power Board
Redwire, I have been working a similar issue with a Hanny board that you refer to above.
Currently I have my board working, but the minute that I attach a Peltier to it, my output voltage drops from about 8.5 VDC to around 1.5 V.
I am still scratching my head trying to figure this out, and 123kenny have been helping, but I am wondering if you have higher resolution versions of the schematics that you post here? They might help me figure out what should be happening.
Thanks-acornish...Leave a comment:
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Re: Wine Fridge Power Board
Thanks Kenney123, I will do that and post the results when I can. Good luck with the repainting and the move. I hope all goes well for you and thank you again for your insightful help.Leave a comment:
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Re: Wine Fridge Power Board
keeney123
Thanks. WRT to the short, it was rather my fault. When I replaced the transistors I used a conductive thermo-compound (a stupid rookie mistake). To get the board to "work" I re-replaced the transistors (all of them) as well as a number of diodes and resistors that were faulty. I picked up a specific transistor/diode tester to check these out and replaced the "burnt" one with identical parts. As well, I used a NON-conductive thermo-compound when I put it all back together, so no fireworks. It does sound like I...Leave a comment:
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Re: Wine Fridge Power Board
Keeney123, yes you are correct, both the fans and the Peltier are rated for 12v DC. Any idea why the board's out put is so low? At best I will see 6v, but with the Peltier attached this drops to less than 2.
Thanks again ALeave a comment:
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Re: Wine Fridge Power Board
So, I am back at this again after a bit of a break. The good news is that the board now works. The fans turn as they should and everything is behaving itself. The board puts out about 5.5 to 6 V when measured at the point where the peltier unit connects.
However, the "bad" news. When I connect the peltier unit, the fans stop and the output voltage drops to about 1.6 V.
I know that the peltier works as I have tested it with an independent 5 V power supply and it gets very warm and very cold as it should.
...Leave a comment:
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Re: Wine Fridge Power Board
Thanks again-I had wondered about that second transistor as it did appear connected to the board. I will continue looking for the short.Leave a comment:
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Re: Wine Fridge Power Board
oops, my question in the second paragraph should have read:
"Could the lack of connection between the heat sink and the COLLECTOR on the upper transistor be part of the problem". I typed emitter by mistake.Leave a comment:
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Re: Wine Fridge Power Board
kc8adu,
OK, I have added a rubber insulator, however the tab of the transformer is still electrically connected to the heat sink. Referring to my image of the back of the board, the lower transistor's collector is connected to the heat sink. This is not the case with the upper transistor, which is isolated due to the "scratches" put in the board. Again, these were there when the unit came to me.
Could the lack of connection between the heat sink and the emitter on the upper transistor be part of the problem?
...Leave a comment:
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Re: Wine Fridge Power Board
So, the fun continues. After replacing the two 13005 transistors on the board, checking the caps and replacing the resistors, I plugged it in and almost immediately it shorted/arced in the back of the board (see photo-I have included photos of both sides of the board).
It was mounted back into the fridge but WAS NOT in contact with the fridge itself-so that wasn't it. Of course, this blew the fuse and the 13005 transistors, which I have once again replaced, but now it is really dead when I try to power it up. The Caps still look OK no...Leave a comment:
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Re: Wine Fridge Power Board
Great thanks Budm, it is very much appreciated
ALeave a comment:
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Re: Wine Fridge Power Board
Budm, thanks, that makes sense. I also understand what you mean by 3 pin combination testing now.
Is this image better?
Thanks-A...Leave a comment:
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Re: Wine Fridge Power Board
Keeney123, with respect to budm's comments, no, I am not sure what "3-pin combination testing" is. I believe the "devices" are transistors-part of the inverter stage of the power supply-but I will have to google how to test them. I have tested the diodes near the heat sinks and large caps and they appear fine
I did notice the "scratches" on the board, but assumed that they were there from production. I will follow through your advice and test for shorting on the AC part of the board. I did notice on Friday...Leave a comment:
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Re: Wine Fridge Power Board
Hi there, If I could jump on this thread. I have a similar board to the one original shown (pic attached). When it came to me it was being used in a small Danby refrigerator and the most apparent problem was a dead fuse near where the 120V AC power supply came to the board. This was a 2.5A/220V fuse that I replaced.
When I went to power the unit up again, the fuse once again blew indicating a deeper problem. So, after inspecting the board, testing caps, and scratching my head, I am a bit stuck. The components on the board look OK and I...Leave a comment:
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Re: Samsung 305T Plus issues
Update:
So I received new FSD-211 chips from China today, after a bit of soldering and a replacement of the "green" fuse that kept popping the monitor works perfectly.
Apparently legal issues aside, these chips are still available. They were about $3 USD each, in the end shipping was more expensive. However for a $20 investment I now have a fantastically large monitor to use. I just hope it fits on my desk
Thanks again to everyone for their help, it was greatly appreciated.
ALeave a comment:
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Re: Samsung 305T Plus issues
Thanks for that additional information. I was aware I might have problems finding a 211 chip, so I am going to see if I can "salvage" one from an old cell phone charger or something while at the same time see if I can order one online. Alibaba.com [I]claims [/I]to have them, but who knows, I will have to see.
Again, I do appreciate the help. ARe: Samsung 305T Plus issues
Thanks for that additional information. I was aware I might have problems finding a 211 chip, so I am going to...Leave a comment:
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