QUOTE(asenrzhang @ Mar 20 2018, 07:44 PM)
What material are y......needs 32 of them.
Do you feel sound quality improvement after replacing these capacitors?
Check the new photos i've added to my previous postFor the sound quality i´m not sure because i cannot make a direct measurement with factory unit, but i will think of yes becuase of MUSE instead of Jun Fu junk.
QUOTE(asenrzhang @ Mar 20 2018, 07:44 PM)
Does the color of wires between PSU board and APB board means something or it's just random color?
It's just a random color ribbon cable which i had availible.
QUOTE(asenrzhang @ Mar 20 2018, 07:44 PM)
Again, Nice wiring!
Detachable wire, that will make life convenient.
And thanks for the model name of pin header (housing): XH (2.54mm). I may try to replace it too.
No problem, check the new photos, there are types of connectors i've replaced wroted in the pictures.
QUOTE(asenrzhang @ Mar 20 2018, 07:44 PM)
Can't believe you replaced the switch too.
the old one was all covered by degraded glue and it was less cost and time consuming to replace it for new one instead of cleaning and scraping old glue.
QUOTE(asenrzhang @ Mar 20 2018, 07:44 PM)
There're two dark green stuff on top of each transfomer, What is that? And what are they used for?
Thick sticky tape as only a temporary protection of the tranformers while the board was upside down on the wokbench to avoid damage the transformers because these was the highest parts before all big caps was soldeded.
QUOTE(asenrzhang @ Mar 20 2018, 07:44 PM)
How do you custom the heat sink (drilling), all by yourself, or bought from shop which provides customing service?
I've drawn it in autocad software first and then give the drawing to the shop which manufactured the final product.
QUOTE(asenrzhang @ Mar 20 2018, 07:44 PM)
I see Nichicon GR series capacitors, which has longer life (10000 hours) than GX series (5000 hours), but I can't found a seller selling this one on local internet market (taobao).
Ripple current is slightly smaller (1.4A) than GX series(1.55A), and a little bit taller (40mm) than orginal one (35mm), is that ok?
I've choosen all electrolytic caps with the highest possible life rating availible at digikey.com. The height is OK, there is still gap about 7mm between the caps top and heatsink so yes it is OK.
QUOTE(asenrzhang @ Mar 20 2018, 07:44 PM)
Wait, L11 unsoldered? Only one leg connected to board? Does it work?
It is only a inductor connected to one side of LINEAR REG / DIODE heatsink where the other side is not connected anywhere, so it can be as open end and yes it is working well.
QUOTE(asenrzhang @ Mar 20 2018, 07:44 PM)
Working temperature when power on is around 35-40°C? That's a WOW!
I have no idea about 2-3dB louder, but that sounds good.
I the summer i expect even higher temperature but i've added bigger FAN (check the new photos) and waiting for hotter days to measure.
2-3dB more measured with iphone app that measures sound level and the units are dB.
QUOTE(asenrzhang @ Mar 20 2018, 07:44 PM)
About the sound absorbing cotton, does it prevent fire? I mean, if, if there's a spark occured in it sometime for some reason, will it burn the box?
By the way, had you tried to replace those operational amplifier chips on APB boards? There're fourteen '072C' and one another on it. The guy whom I'm fixing for want those op-amps to be replaced too, but I don't know what I'm doing if replacing them, and I have no strong feelings that replacing op-amps will improve sound quality. Also, after read some posts, I known oscillation issue may occur after op-amps been replaced. Like I said, I don't know what I'm doing if replacing them.
It is some kind of very thin plastic fibres cotton, not a regullar cotton. I've tried to burn it and it melts and it is flamable but i must hold direct fire a couple of seconds to it to set it on fire. I think a small random spark will not set it on fire, only make a small melted spot.
For the op-amps i've left them alone, no replacing. Never heard about replacing them is needed. I've got several S750 units. All AMP boards where nearly OK, some of them has broken C40 and one has broken C41. After replacing C40, C41 and for sure C39 was all AMP board fully working.
This post has been edited by MichalD: Mar 29 2018, 03:50 AM