Hi Eveyone,
I'm a newbie here. I've got a dual AKM DAC board which I purchased some time ago from Aliexpress and have only just gotten around to powering up. I've partially built the enclosure up and i've tested the power supplies are delivering the correct voltage to each of the terminals. However, i'm getting a blank screen on the LCD panel (although it does light up) and the selector switch does not seem to scroll through inputs like it should. I've also connected a digital source via coax and I get no sound at all. Not sure where to start looking for possible issues, but if anyone has any ideas i'd be grateful. I've tried contacting the seller on Aliexpress, but I purchased this a while ago and am expecting to get a brush off if I even get a response at all! Photos attached. Note that there is an LED on the back of the display screen which isn't lighting up, but not sure if this only lights when a remote control IR is detected (my board didn't come with any remote).
Anyone got any ideas? Thanks in advance!
Andy.
I'm a newbie here. I've got a dual AKM DAC board which I purchased some time ago from Aliexpress and have only just gotten around to powering up. I've partially built the enclosure up and i've tested the power supplies are delivering the correct voltage to each of the terminals. However, i'm getting a blank screen on the LCD panel (although it does light up) and the selector switch does not seem to scroll through inputs like it should. I've also connected a digital source via coax and I get no sound at all. Not sure where to start looking for possible issues, but if anyone has any ideas i'd be grateful. I've tried contacting the seller on Aliexpress, but I purchased this a while ago and am expecting to get a brush off if I even get a response at all! Photos attached. Note that there is an LED on the back of the display screen which isn't lighting up, but not sure if this only lights when a remote control IR is detected (my board didn't come with any remote).
Anyone got any ideas? Thanks in advance!
Andy.
Attachments
Does it do anything when you push in the rotary control like a button?
Noticing that it has two power transformers, do both of them automatically get energized when you plug it in?
Does anything at all see to work right with this unit and whatever controls it has?
Have you tried pointing any light-based remote control at it and pushing some remote buttons?
What test instruments do you have?
Have you ever reverse engineered a small dac?
Noticing that it has two power transformers, do both of them automatically get energized when you plug it in?
Does anything at all see to work right with this unit and whatever controls it has?
Have you tried pointing any light-based remote control at it and pushing some remote buttons?
What test instruments do you have?
Have you ever reverse engineered a small dac?
Hi Mark,
Thanks for responding. The rotary controller does push in like a button but it does not do anything. The rotary control moves both ways which I understood should be to select the input but again it does nothing in my case.
I did try to point a light based remote at it from a dvd player but none of the buttons seems to have any effect. There is a led on the back of the control panel and display board which doesn't light up but this might be only when a remote signal is detected.
Both transformers are energised together a 15-0-15 AC supply and a dual 9v AC supply and I've checked the voltage at the inputs to the board and all is okay. I haven't tried to test the Dc power on the board itself yet. All I have is a multimeter!
I'm about at the limit of my understanding here already - I thought if would just fire up first time, but that was probably a bit naive.
Thanks for responding. The rotary controller does push in like a button but it does not do anything. The rotary control moves both ways which I understood should be to select the input but again it does nothing in my case.
I did try to point a light based remote at it from a dvd player but none of the buttons seems to have any effect. There is a led on the back of the control panel and display board which doesn't light up but this might be only when a remote signal is detected.
Both transformers are energised together a 15-0-15 AC supply and a dual 9v AC supply and I've checked the voltage at the inputs to the board and all is okay. I haven't tried to test the Dc power on the board itself yet. All I have is a multimeter!
I'm about at the limit of my understanding here already - I thought if would just fire up first time, but that was probably a bit naive.
One might suppose that if a spdif signal were presented at the appropriate input, then the knob turned to the spdif position, and then pushed in, that the input might thereby be selected (that is if the knob were pushed while a valid signal was present. Maybe a low cost universal remote could be tried in case it happens to be settable on on a useful code-table
Other than that type of thing, what is usually needed in some cases is some reverse engineering to produce a schematic. That and an oscilloscope could likely get it working.
With cheap Chinese products like a dac board product usually they only use a two layer board to keep costs down. That can be a good thing in cases like this; makes it fairly trivial to reverse engineer. It also tends to be a bad thing in terms of SQ if the unit were to be working.
The other thing is that an moderately fast oscilloscope, preferably a 2-channel, 100MHz+ bandwidth (200MHz is good), is pretty much the minimum for playing around with diyaudio in the dac area.
Don't know how you might feel about any of that stuff.
Other than that type of thing, what is usually needed in some cases is some reverse engineering to produce a schematic. That and an oscilloscope could likely get it working.
With cheap Chinese products like a dac board product usually they only use a two layer board to keep costs down. That can be a good thing in cases like this; makes it fairly trivial to reverse engineer. It also tends to be a bad thing in terms of SQ if the unit were to be working.
The other thing is that an moderately fast oscilloscope, preferably a 2-channel, 100MHz+ bandwidth (200MHz is good), is pretty much the minimum for playing around with diyaudio in the dac area.
Don't know how you might feel about any of that stuff.
Any trimpot on LCD board ? Adjust until LCD show some readable text not block bar. Maybe it MCU issue.
If it came with IR remote try powering off/on from remote
If it came with IR remote try powering off/on from remote
I'll check for the contrast trim on the LCD. Thanks didiet78, but I don't think that it is just a display issue as I'm unable to get sound when a digital source is added. What I haven't tried is pushing and turning the selector at the same time so will try that later. It didn't come with a remote - I think this controller and display are used for several boards.
I have tried adjusting the potentiometer on the LCD panel but it doesn't reveal any text on the display it is just the blocks as per the photo.
The DC power on the board seems to be working ok, so I'm thinking the most likely culprit is the control cable/unit. This somehow looks a bit flakey compared to the main board. I'll see if I get any joy from AliExpress but if anyone has a similar control /display board lying around from a stalled project then let me know!
The DC power on the board seems to be working ok, so I'm thinking the most likely culprit is the control cable/unit. This somehow looks a bit flakey compared to the main board. I'll see if I get any joy from AliExpress but if anyone has a similar control /display board lying around from a stalled project then let me know!
What looks like an LED on the back of the display panel is probably an infrared receiver. The pot would then be to adjust the display for maximum legibility. The Infrared receiver must be lined up with a hole in the front panel so it can receive signals from an infrared remote control. Once all that stuff is right, then you can go hunting for a remote control code which is likely to be in use. Most of those simple remote devices use one of a few common codes.
Also, its usually possible to decode I2C control signals with a cheap logic analyzer like this one: https://www.ebay.com/itm/124238666414?itmmeta=01J2VE90F22JX9J5H8745EXRFR&hash=item1ced339aae:g:Xs4AAOSwQ7haxEa1&itmprp=enc:AQAJAAAA4O/7hXqLQGvVVwqo6jYMoCSdUglLv5uZn8G9I46BdA7duFAZSR5cctzr1UANgWmDfRqZdCo1m/75gvJUNgY4gW906o8AFQ/v3Ikes+HJuuV2SHmnD9JH5qXSzd/3++0+L7mFlhBrFXHT8qf1RROf56ClwdM2o4CUELBNwHl2tyxk9uzJSty2F88X+huoxTE9jtvUshYWGDoLyGLXpGNfHKmWIymWI94VBV3bkgCwlb2A6bBoeAwz9aDp13hhu4F5MAkQ0gdV73Ik9C1max03uiZNfYIpw4iL2TMd9ZDIr8Rd|tkp:Bk9SR86HpO6WZA ...its not very good, but it is good enough for I2C.
Also, its usually possible to decode I2C control signals with a cheap logic analyzer like this one: https://www.ebay.com/itm/124238666414?itmmeta=01J2VE90F22JX9J5H8745EXRFR&hash=item1ced339aae:g:Xs4AAOSwQ7haxEa1&itmprp=enc:AQAJAAAA4O/7hXqLQGvVVwqo6jYMoCSdUglLv5uZn8G9I46BdA7duFAZSR5cctzr1UANgWmDfRqZdCo1m/75gvJUNgY4gW906o8AFQ/v3Ikes+HJuuV2SHmnD9JH5qXSzd/3++0+L7mFlhBrFXHT8qf1RROf56ClwdM2o4CUELBNwHl2tyxk9uzJSty2F88X+huoxTE9jtvUshYWGDoLyGLXpGNfHKmWIymWI94VBV3bkgCwlb2A6bBoeAwz9aDp13hhu4F5MAkQ0gdV73Ik9C1max03uiZNfYIpw4iL2TMd9ZDIr8Rd|tkp:Bk9SR86HpO6WZA ...its not very good, but it is good enough for I2C.
Thanks Mark. The IR receiver is actually on the front of the LCD panel so I'm still not sure whether the led on the back is supposed to light up.
I have been trying to source a new controller unit for this, but it seems that very few if any sellers are selling AKM boards now - probably due to supply issues.
I did see this board with a very similar ak4118 control board and display.
https://www.elecbee.com/fr-31037-AK...l-DAC-Audio-Decoder-Board-D3-003-Without-USB-
I thought about buying this and seeing if I can use this controller with my board. It looks the same. Does anyone know if the software loaded into these controllers is specific to the AK4118 receiver chip or the dac chips themselves?? This is an AK4990 board same as mine, but a single rather than dual chip version? Is this likely to work??? Any views appreciated!
I have been trying to source a new controller unit for this, but it seems that very few if any sellers are selling AKM boards now - probably due to supply issues.
I did see this board with a very similar ak4118 control board and display.
https://www.elecbee.com/fr-31037-AK...l-DAC-Audio-Decoder-Board-D3-003-Without-USB-
I thought about buying this and seeing if I can use this controller with my board. It looks the same. Does anyone know if the software loaded into these controllers is specific to the AK4118 receiver chip or the dac chips themselves?? This is an AK4990 board same as mine, but a single rather than dual chip version? Is this likely to work??? Any views appreciated!
As the controller boards and dac boards look very similar it is quite possible that also the firmware is similar. So it is possible that the single dac controller board can control the SPDIF transceiver (AK4118) on your board and also one of the AK4490 dac ICs. The other AK4490 has different I2C slave address so it is less likely to control that as well. So you would end up with a mono AK4490+AK4118 board.
You could also try to swap the MCUs as they seem to be socketed. This would help is the fault is in your existing controller board instead in the MCU.
Have you checked that the cabling between MCU and DAC boards is correctly oriented? Also you could try if the controller board works without the encoder.
You could also try to swap the MCUs as they seem to be socketed. This would help is the fault is in your existing controller board instead in the MCU.
Have you checked that the cabling between MCU and DAC boards is correctly oriented? Also you could try if the controller board works without the encoder.
Thanks for the reply bohrok. I thought that this might not be as simple as switching the controllers!! It's challenging knowing when to give up with projects like this. I've already spent quite a lot on case, transformers etc! I'll try the suggestions you and Mark have made and then decide what to do!
I might buy the board I linked, but it is good to be forewarned that it might not be a straight swap!
Alternatively I might be better scrapping the AKM board and going for something else completely. Anyone have any suggestions on what the best pre- assembled DAC boards are right now up to 200 dollars ish? I got the AKM one a couple of years ago (stupidly didn't check it straight away!) but it seems that most more recent boards use ESS or other chips now. Problem is that the transformers I got for this board are unlikely to be compatible with a new board. Oh the agony (or fun !) of DIY audio!!
I might buy the board I linked, but it is good to be forewarned that it might not be a straight swap!
Alternatively I might be better scrapping the AKM board and going for something else completely. Anyone have any suggestions on what the best pre- assembled DAC boards are right now up to 200 dollars ish? I got the AKM one a couple of years ago (stupidly didn't check it straight away!) but it seems that most more recent boards use ESS or other chips now. Problem is that the transformers I got for this board are unlikely to be compatible with a new board. Oh the agony (or fun !) of DIY audio!!
One solution would be to write your own controller code. Its usually fairly easy to do once I2C bus programming is understood.
I once wrote about how to program a dac using an Arduino. Links to some posts in the attached file.
A friend got some frequency counters from E-Bay.
Some didn't work, but when the PICs were programmed with a copy of the firmware from the ones that did work, then they worked too.
They sent some units out with un-programmed PICs.
Some didn't work, but when the PICs were programmed with a copy of the firmware from the ones that did work, then they worked too.
They sent some units out with un-programmed PICs.
Thanks for the latest suggestions. The board is currently with my father in law who has offered to take a look. I'll be seeing him in a couple of weeks and will update further then.
My father in law has been over the board and believes that the dac board appears to be powered up and functioning as expected. It appears the issue is with the controller - most likely johnnyx suggested that the software has not been flashed onto the chip. I think that trying to control this board with adruino or similar is probably beyond my level of skill and patience (at least in short term) so I've got two options to try and find a new controller board from a similar dac ( I did read on the dual ak4399 dac thread that there is some cross compatibility between controllers as many different versions of this dual akm board have been produced). Alternatively I can shelve this board and start again with something new. Ideally I'd like to try a different controller board and see what happens, but getting hold of something is not easy.
Ok.. I've decided to buy a new board and it arrived yesterday. This one is a dual ak4396 board - quite a lot cheaper than the other board, but it works!! Woohoo! I'll use this board as a stop gap whilst I try and find a solution for my ak4490 board.
I do notice that that one of the LM317t voltage regulators on this new board gets quite hot - too hot to touch the heat sink after a couple of minutes. It's one of the regulators on the 9v side of the board which gets particularly warm, the other 3 are ok. I've left the dac running for 40 mins or so and nothing cuts out so I'm assuming it's all ok! Any thoughts appreciated!
I do notice that that one of the LM317t voltage regulators on this new board gets quite hot - too hot to touch the heat sink after a couple of minutes. It's one of the regulators on the 9v side of the board which gets particularly warm, the other 3 are ok. I've left the dac running for 40 mins or so and nothing cuts out so I'm assuming it's all ok! Any thoughts appreciated!
