Hi, I need some advice from the experts in the APC recapping department :-)
Got an older APC SMT1000I, 2011 model without fan that I would like to save if possible.
It came with 2 noname 7Ah batteries inside and some packing foam to fill the space, someone was creative :-)
It's working fine, tested it with light load, it charges batteries, passes self test, no strange behaviour.
Except for some quiet high freq hissing coming from a transformer compartment. Its hissing all the time, with or without battery, on battery...
Starts a second or two the after connecting mains power, after some relay clicks.
Don't know if hissing is normal for those APC units, but because of age, I would like to recap it before use.
It has 2 PCBs, large main one covering the whole top of the case and a smaller one that looks like some kind of PSU stuck in the back corner behind the transformer.
Right about where the hissing is coming from :-)
Main PCB is clean, no bulged caps, but as I was able to research, some small caps always fail on the APCs.
Small PCB is a different story, it was partially covered in some black soot in the region between the blue Y capacitor, transformer and two larger caps.
After treatment with isopropyl and a soft brush board is squeaky clean, no burnt components, just some darker spots from the heat on the back.
The plan is to replace all electrolytics :-)
I'm a hobbyist, not a pro, so I apologize in advance for my lack of knowledge :-)
My questions:
1. I was able to find the spec sheets of all the caps except the two SMD.
Pictures with markings and position attached.
Those have markings:
Code:
19 33 35V
Code:
D1 47 35Z
2. The small PCB is bothering me, where did that black dust come from?
Nothing visibly blown, that protection cap is not open, it tested in circuit to something like 4.3nF which sould be in spec.
Diodes around it are not shorted. Could it be from the transformer?
3. This big cap at position 12 (C85) is EPCOS / TDK B41848-A7278-Z.
I'm having trouble at finding a replacement, any suggestions about that?
4.Anybody knows what is this smaller PCB for, some charger for battery or...?
5. Is there any way of detaching the black wire coming from battery connector in the back? It's the only one soldered directly to PCB :-)
Main board caps
Code:
Position PCB mark Brand / series Values 1 C610 OST RLG 47uF 16V 2 C60 Uknown SMD 33uF 35V??? 3 C606 Uknown SMD 47uF 35V??? 4,7,9,10,11 C75,C35,C114,C100,C115 Lelon SSG 22uF 16V 5 C77 Lelon RGA 47uF 63V 6 C85,C102 IC RZM (Illinois) 330uF 25V 12 C85 EPCOS / TDK 2700uF 40V
Code:
C903 JNC JN472M (had some soot on it) C917, C918 Jianghai CD 263 22uF 400V C904 IC (Illinois Capacitor) 22uF 50V C938 IC (Illinois Capacitor) 10uF 50V C906 Jamicon TK 330 uF 5
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