I got the rev 3 from aliexpress seller. i previous posted the link.
Opened it up, had some aluminium dust on the inside of the case, on one of the sides. i used a vacuum to remove the Au dust. It worked but i fear that if i had left it, a bit of Au dust would fall off the side and have shorted something out.
Opened it up, had some aluminium dust on the inside of the case, on one of the sides. i used a vacuum to remove the Au dust. It worked but i fear that if i had left it, a bit of Au dust would fall off the side and have shorted something out.
With SMD technology in particular, the insulation distances are very narrow and small metal particles, like a small piece of cable strand, can cause fatal damage.
My compressor (5 bar) is an essential tool for cleaning electronics, in particular my computers where dust can prevent cooling after few months.
A 5 bar compressor (5 liter tank) is cheap to buy. Use safety glasses!
My compressor (5 bar) is an essential tool for cleaning electronics, in particular my computers where dust can prevent cooling after few months.
A 5 bar compressor (5 liter tank) is cheap to buy. Use safety glasses!
...maybe it was to late to be focused...
Hello
yesterday night i want to check the smps. so i opened it I did some pics.
the smps housing is earth grounded and therefore i add some extra pin to connect the scope proper to it.
smps switched on without load.
i want to measure the noise but if i looked a t the scope i was totally confused.
i do not have a differential probe for my scope and i mentoined that i look at the noise with earth grn and the positive output.
yellow positive output
blue negative output
my DMM shows without load 14.99V --> ok
so how can i measure the noise???why i get 66V to earth. 50HZ is the frequ by the network (230V/50Hz)
mybe it was really to late for my ...to realize what happend here...
what did i wrong?
Hello
yesterday night i want to check the smps. so i opened it I did some pics.
the smps housing is earth grounded and therefore i add some extra pin to connect the scope proper to it.
smps switched on without load.
i want to measure the noise but if i looked a t the scope i was totally confused.
i do not have a differential probe for my scope and i mentoined that i look at the noise with earth grn and the positive output.
yellow positive output
blue negative output
my DMM shows without load 14.99V --> ok
so how can i measure the noise???why i get 66V to earth. 50HZ is the frequ by the network (230V/50Hz)
mybe it was really to late for my ...to realize what happend here...
what did i wrong?
Attachments
I see no safety clearance(about 7mm of the air gap to a "COLD" side) on the "HOT" side of your SMPS. It's not necessarily deadly danger for you, but the company which selling such stuff is under potential risk. For example, a user may sue the company and get few hundreds pcs because an uncompliant product has CE mark and so on.
pins of TO-220 are <3mm to heatsink, it is enough to fail "High Pot" test. Actually, they should have a lot of room inside because the power is tiny for such size. You can buy 3x power for a less money with no safety problem if check for the PC desktop ATX SMPS. 12VDC need to adjust for 15VDC that's it.
...away from the safety issue of this smps....
so its not possible to measure the ripple from this outputs , i guess ?
SQ was better for the fx502spro and the only noisy part is this cheap fan!
its a 40mmx40mmx10mm 15V 0,07A cheap sanai fan.
so for auido...
the first listening test was better for amp1 (LM49720) than the original smps
should i avoid this smps, do i get some influences to my DAC ?????.= its earth grounded
so its not possible to measure the ripple from this outputs , i guess ?
SQ was better for the fx502spro and the only noisy part is this cheap fan!
its a 40mmx40mmx10mm 15V 0,07A cheap sanai fan.
so for auido...
the first listening test was better for amp1 (LM49720) than the original smps
should i avoid this smps, do i get some influences to my DAC ?????.= its earth grounded
Last edited:
...good evening..recheck the smps...
so ...this smps is crazy and i am not sure to use it anymore
pic 1 connected but not switchend on - 116V to earth!
pic 2 connected and switched on but no load - -63V
pic 3 connected, switched on and 2ohms load - 63V , 14,76V and 7 amps
i rechecked the rms with my DMM and its true !
so this SMPS is danger!
what next...waht should i do?
so ...this smps is crazy and i am not sure to use it anymore
pic 1 connected but not switchend on - 116V to earth!
pic 2 connected and switched on but no load - -63V
pic 3 connected, switched on and 2ohms load - 63V , 14,76V and 7 amps
i rechecked the rms with my DMM and its true !
so this SMPS is danger!
what next...waht should i do?
Attachments
116Vac looks very much like half 230V. Could it relate to an old trick using two equally size (safety) capacitors going one from phase (230V) to chassis and one from 230V return to chassis?
It was a design intended for buildings without earth.
I recall a weak tingling feeling in my fingers touching such an apparatus. It was not dangerous as the current was very low.
Try to measure the DC impedance between the one of the 230V plug contacts and chassis and then the other plug contact and chassis. It should exceed 1MOhm in both cases.
It was a design intended for buildings without earth.
I recall a weak tingling feeling in my fingers touching such an apparatus. It was not dangerous as the current was very low.
Try to measure the DC impedance between the one of the 230V plug contacts and chassis and then the other plug contact and chassis. It should exceed 1MOhm in both cases.
Hi FF
you are my friend
thanks for your experiance. yes i had this buzzy feeling.
actually i am on business trip to graz.i am back tomorow...so at latest i will try ion the weekend.
finaly this smps sounds better than the original.
thx FF
..opamp BB2134 vs LM49720...
hi to all
just a first impression after the burn in for the LM49720.
the opamps are nearly from the same family and sounds very fine. better than the original NE5534...what ever..
compare with the original smps:
blue pcb v3 amp with lm49720
white pcb v5 BB2134
after appr. 40-50 hours i will give the LM49720 the better sound because the BB2134 is more "sounded" in the bass area. i mean sometimes he is too punchy and boost too much where it is not "needed".
Sound stage is fine and the in deepness the BB 2134 is slightly better.
next test with longer burn in and better smps.
christian
hi to all
just a first impression after the burn in for the LM49720.
the opamps are nearly from the same family and sounds very fine. better than the original NE5534...what ever..
compare with the original smps:
blue pcb v3 amp with lm49720
white pcb v5 BB2134
after appr. 40-50 hours i will give the LM49720 the better sound because the BB2134 is more "sounded" in the bass area. i mean sometimes he is too punchy and boost too much where it is not "needed".
Sound stage is fine and the in deepness the BB 2134 is slightly better.
next test with longer burn in and better smps.
christian