Blown OPA365 (OAVQ)
Hi bambadoo, it's look like you have blown one of the buffer IC (next to U33 mark). Have you checked polarity of (to late now)big caps before powered?
If you are lucky you will have to replace only one buffer IC and/or -5v reg.
btw If any of you guys are thinking that all this mods are to much for you and thinking to buy a new ver2 board (Vref mod done out of the box) and willing to sale your ver1 unmodified board please PM me (only 0.01%)
thank's
Danny
Hi bambadoo, it's look like you have blown one of the buffer IC (next to U33 mark). Have you checked polarity of (to late now)big caps before powered?
If you are lucky you will have to replace only one buffer IC and/or -5v reg.
btw If any of you guys are thinking that all this mods are to much for you and thinking to buy a new ver2 board (Vref mod done out of the box) and willing to sale your ver1 unmodified board please PM me (only 0.01%)
thank's
Danny
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Every "voltage" at J2 is ok.
However I got about 3-4mv in the vref
What could be wrong? Desoldered the vref mod for one channel also. No change. The polarity for the 16caps are ok and just as described from hifiduino site.
One good thing. The poweron/off issue is gone... Absolutely silence since nothing arrive at the output..
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Your application can't be solved with one DAM either. If you don't use 4 boards. And you could use 3 toslink splitters to create 4 Toslink lines form one source... so.. maybe.
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Get 3. But the first might need to be active.
Digital Toslink Optical Fiber Audio Y Splitter 1 to 2 Cable Adapter s PDIF HDTV | eBay
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Digital Toslink Optical Fiber Audio Y Splitter 1 to 2 Cable Adapter s PDIF HDTV | eBay
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Hi, will check later today but I suspect that the reference voltage is not present.
But I have some additional information.
When I did the mods (between the 16 cap mod which worked and the rest of the vref mod including the poweron/off 27k4r resistor mod) I also thought of soekris early post regarding the 6 main 820 uf caps.
http://www.diyaudio.com/forums/vend...magnitude-24-bit-384-khz-178.html#post4225082
I have some of them on hand so of course I could make the switch.
But I did not manage to remove the original caps. I tried with one. One of the RC filter caps.
Up in the right corner. I started using a heater gun for the purpose and had to give up.
Could this be the fault? Have I toasted the cap (overheat inside) and made sure the vref voltage is not present?
If so - would really change these caps (in good manner) make it work again?
It measures approv 10.5Vdc across its terminals.
bambadoo, the RC caps supply the output opamps, so if you are using the raw output they shouldn't matter - that is unless they are pulling the supply down. As you are measuring 10.5Vdc, I would expect this not to be the cause of your problem.
You need to measure that you have got +/5V for the opamps, and +/-4V for the references. This will give an indication of where the problem is.
You need to measure that you have got +/5V for the opamps, and +/-4V for the references. This will give an indication of where the problem is.
bambadoo,
I found one can just PULL those electrolytics off of the board. The big ones after the rectifier were especially easy.
My intention was to destroy them by pulling off the aluminum jacket and then having better access to the solder points but as I did this I found they simply came off with firm even pressure. No yanking! Pull them off in the direction of the pads so you pull against one tab at a time. Look at a spec sheet for where the solder points are, I worry an explanation within this post will not be accurate enough.
I did pull up a solder pad on the caps after the 5 volts reg but luckily it was a ground pad and is easy enough to work around.
If you do not use the balanced buffer output then you can experiment with the two furthest from the end which only affect those op-amps. If you cannot get those to come off with my "method" your board may not be as compliant as mine was.
I attempted to use a soldering iron but the pads are very difficult to touch and I worried I could do more damage to other components with the heat.
I removed all of the electrolytic caps, this way, on my board.
Worth a try?
I found one can just PULL those electrolytics off of the board. The big ones after the rectifier were especially easy.
My intention was to destroy them by pulling off the aluminum jacket and then having better access to the solder points but as I did this I found they simply came off with firm even pressure. No yanking! Pull them off in the direction of the pads so you pull against one tab at a time. Look at a spec sheet for where the solder points are, I worry an explanation within this post will not be accurate enough.
I did pull up a solder pad on the caps after the 5 volts reg but luckily it was a ground pad and is easy enough to work around.
If you do not use the balanced buffer output then you can experiment with the two furthest from the end which only affect those op-amps. If you cannot get those to come off with my "method" your board may not be as compliant as mine was.
I attempted to use a soldering iron but the pads are very difficult to touch and I worried I could do more damage to other components with the heat.
I removed all of the electrolytic caps, this way, on my board.
Worth a try?
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I can find +-/5V for the opamps. However nothing for the references. Well approx 1.5mv
Or maybe it is the 27k4 mod itself?
This little bastard here. (With a red ring) Can this be fried? I desoldered and try to "Ohm" it. Infinite. Is it a resistor or something else? It is too small for me to tell.
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If your filters will be implemented in DAM, you can simply connect the data line from TOSLINK receiver into all dacs in parallel. No need for optical splitters, although it implies all DAM boards need to be located close to each other.
If you want to do filtering in computer, then of course you will need separate channels to the DACs.
I am planning to do all DSP/crossovers computer side, mapping each speaker channel to an individual digital output on a multi digital output pro sound card. Then probably multiple DIY DACs per channel.