Singxer SU-2
Dec 4, 2023 at 10:54 AM Post #184 of 215
Use a 100nF smd ceramic in topmost position.
You do not need to place anything in the area with the red X.
The other side is for mounting the crystal.
Triangle is pin1
Thanks so much @b0bb . Glad I asked asked as Audiophonics stated to put a cap in all three locations.

One other novice question. I purchased the polarized replacement 47uf caps that you suggested. What would be the easiest way to discern which side is positve/negative on the existing capactitors on the PCB?
 
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Dec 6, 2023 at 8:25 PM Post #186 of 215
@b0bb , I metered out all the caps. I accomplished this by taking a probe to case of the crystal and checking both sides of the caps you pointed out to replace

The ones I circled in yellow did not have a polarity, do you recall that to be the same? Is it safe to say orientation does not matter in these locations? The ones I circled in green, I won't be able to change because of the Kitsune voltage regulators that are installed. Looks like there's been somer rework in this area and I am reluctant to touch the pads. Does it pose any issue if I replace all the ones in red only and possibly the two in yellow? I've marked the + side with a star for all that have a polarity..

Come to find out, I had already replaced the Accusilcon crystals with Crystek! Man it sucks getting old! If anyone needs a pair of Crysteks mounted on adapter boards to try this mod, feel free to message me
image_50727681.JPG
 
Dec 8, 2023 at 10:12 PM Post #187 of 215
@b0bb , I metered out all the caps. I accomplished this by taking a probe to case of the crystal and checking both sides of the caps you pointed out to replace

The ones I circled in yellow did not have a polarity, do you recall that to be the same? Is it safe to say orientation does not matter in these locations? The ones I circled in green, I won't be able to change because of the Kitsune voltage regulators that are installed. Looks like there's been somer rework in this area and I am reluctant to touch the pads. Does it pose any issue if I replace all the ones in red only and possibly the two in yellow? I've marked the + side with a star for all that have a polarity..

Come to find out, I had already replaced the Accusilcon crystals with Crystek! Man it sucks getting old! If anyone needs a pair of Crysteks mounted on adapter boards to try this mod, feel free to message meimage_50727681.JPG
Measure across the caps directly. The yellow caps is on the "dirty" side of the DDC. They have 3.3V across them.
The 3.3V legend is the positive side, double check this is the case for your board.
There are 3 caps that can be replaced as shown.
The pads are large enough to support a larger value solid polymer SMD electrolytic.

Large value ceramics are ferromagnetic, getting rid of them is a step forward to improve things for the USB processor's power supply.

The XO metal cans is the "clean" side ground.
08CC6620-BE73-4566-931D-EAF114AC932A_1_105_c.jpeg
 
Dec 8, 2023 at 10:16 PM Post #188 of 215
Thanks so much @b0bb . Glad I asked asked as Audiophonics stated to put a cap in all three locations.

One other novice question. I purchased the polarized replacement 47uf caps that you suggested. What would be the easiest way to discern which side is positve/negative on the existing capactitors on the PCB?
Singxer already has bypass caps on the board, the 1 cap is sufficient to keep local noise down.

The ideal is to keep either on the adaptor or the motherboard, not both, you risk creating a local ground loop.

SU-2 is quite fussy, I have already run into issues where some crystals don't work unless all the bypass caps are removed from the adapter.
(Your current adapters do not have bypass caps)
 
Dec 8, 2023 at 10:47 PM Post #189 of 215
Measure across the caps directly. The yellow caps is on the "dirty" side of the DDC. They have 3.3V across them.
The 3.3V legend is the positive side, double check this is the case for your board.
There are 3 caps that can be replaced as shown.
The pads are large enough to support a larger value solid polymer SMD electrolytic.

Large value ceramics are ferromagnetic, getting rid of them is a step forward to improve things for the USB processor's power supply.

The XO metal cans is the "clean" side ground.
08CC6620-BE73-4566-931D-EAF114AC932A_1_105_c.jpeg
Thanks again @b0bb. I measured the 3 earlier in the day, they read around .1ma DC across, not 3.3V. Just measured them again and it's the same, barely any voltage reading.

Should I leave all the caps as-is then? I am planning to have the rework done on Monday to swap to the IL711S and TPS7A20, what are your thoughts on the caps in question and all the others.
 
Dec 8, 2023 at 10:52 PM Post #190 of 215
Thanks again @b0bb. I measured the 3 earlier in the day, they read around .1ma DC across, not 3.3V. Just measured them again and it's the same, barely any voltage reading.

Should I leave all the caps as-is then? I am planning to have the rework done on Monday to swap to the IL711S and TPS7A20, what are your thoughts on the caps in question and all the others.
USB needs to be plugged and the audio connection setup. All 3 front panel LEDs on.
Otherwise the USB core goes into low power state.

Measure when there is music going thru the SU2

I would change the caps on the usb side, but if you are unsure skip it.

PS: 0.1mA does not sound right, it should be reading in volts not amps
 
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Dec 9, 2023 at 8:45 AM Post #191 of 215
USB needs to be plugged and the audio connection setup. All 3 front panel LEDs on.
Otherwise the USB core goes into low power state.

Measure when there is music going thru the SU2

I would change the caps on the usb side, but if you are unsure skip it.

PS: 0.1mA does not sound right, it should be reading in volts not amps
Ah, that explains it....I just had the unit on the shop bench. USB was not connected. That's why there was no reading
 
Dec 11, 2023 at 5:28 PM Post #192 of 215
@b0bb I ran into a problem......did the mods and now the SU2 doesn't power on. With the cover off I can see the LED lit on the power supply board but no lights on the front panel. Had a highly skilled solderer at the facility perform the mods, any suggestions as to where to start to troubleshoot? Is it possible my Kitsune unit is somehow different and this mod is incompatible?
IMG_5822.jpg
IMG_5823.jpg
 
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Dec 11, 2023 at 7:21 PM Post #193 of 215
@b0bb I ran into a problem......did the mods and now the SU2 doesn't power on. With the cover off I can see the LED lit on the power supply board but no lights on the front panel. Had a highly skilled solderer at the facility perform the mods, any suggestions as to where to start to troubleshoot? Is it possible my Kitsune unit is somehow different and this mod is incompatible?IMG_5822.jpgIMG_5823.jpg
Check the polarity of your caps, white bar is usually +ve
Your board

newmod.png


My board
oldmod.png



Further details in PM
 
Dec 11, 2023 at 9:17 PM Post #195 of 215
@b0bb thanks as always....


So this is what happens when a sales guy (me) plays engineer!. I marked my drawing correctly, all the stars were the negative side. My rework instruction I wrote to the engineer, told him the stars were positive......

UGH! guess I will have to have them measured to confirm I didn't blow them up? It doesn't appear that anything happened to the board, fingers crossed!
 

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