Re: Focusrite Saffire Pro 40 re-cap
Yeah the solder tickenend trace goes to the filter cap. If it was just a "0" jumper for layout reasons, it would actually connect the heatsink to ground, which makes sense. I also was thinking it might have been some sort of fusible smd.
But i'm anxious to solder some jumper wire instead, maybe it still was some Resistor, probably fine tuned to prevent some stability problems or something.
I hope somebody can check the value for me when they recap their SMPS. Would be very much appreciated.
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Re: Focusrite Saffire Pro 40 re-cap
So.. here are the pictures of the failed Saffire Pro 40 SMPS PCB.
The heatshink for Q1 is where the mains earth wire touched and on the underside you can see the missing R37.
I already cleaned up all the mess, there has been quite some soot after R37 burned out.
If somebody could tell me the value of R37 it would help quite a lot to repair the bugger.
Note that the input protection devices (NTC Thermistor & Varistor) are missing because i unsoldered them for testing.
I found the...
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Saffire Pro 40 SMPS PCB
Pics of my failed Saffire Pro 40 Power Supply3 Photos
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Re: Focusrite Saffire Pro 40 re-cap
I unsoldered the FET and checked it using my multimeter. It should be OK.
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Re: Focusrite Saffire Pro 40 re-cap
No, the blown one is not the sense resistor. In this power supply it consists of 4 Resistors in parallel (2x 1R0 2x 3R3).
I think R37 is part of 2 pull-down resistor in series on the Gate of the FET. R11 is 10k and connects the heatsink to the gate of the FET, R37 connects the heatsink to ground of the Diode-Bridge Rectifier.
No idea why the heat sink is connected in circuit like this anyway?
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Re: Focusrite Saffire Pro 40 re-cap
Hey, thanx for the quick reply!
Yeah, its on the psu. Actually Q1 is the switching Mos-FET, i mistook it for a regulator and R37 is on the underside of the PCB next to a big solder-blop which holds the heatsink. There should be a Silkscreen Label next to it. The blown Resistor is connected to the Output of the Diode-Bridge-Rectifier and via another Resistor (if i remember correctly 10K) to the Gate of the FET.
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Re: Focusrite Saffire Pro 40 re-cap
Hey there!
I also decided to recap parts of my Pro 40, especially the psu and some caps around the mainboard regulators. I noticed that it took more and more time after startup for the locked led to come up (always acompanied by the audible click of some relay). Also for quite some time i have occational problems with some kind of digital distortions where the drivers seems to get a hick-up, which i normaly solve by muting and changing the audio buffer to a different setting. Many different driver version updates and reinstalls...
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