Hello Forum.
I'm in the need for help/advices - because my amp is behaving strangely.
The issue i related to the power - since I can not turn on or off the amp with the on/off push button.
The second that the power cord is plugged in - the display show; volume level, and source - but only in half a second - but then nothing happens - and the unit can not be operated. This happens no matter if the on/off button is set to on or off.
A few times - I managed to turn the unit on (when plugging in/out the power cord several times).
When the power remains long if not to turn the unit on - it plays nicely.
But - another strange thing is - that in these situations - I can not turn off the power using the on/off button. When switched off - the unit just keeps playing.
At first I thought this was an issue regarding the on/off switch it self - but now I'm not sure anymore.
When playing - the unit can suddenly close down - and afterwards I'm back to not being able to turn it on again.
I hope that some of you are familiar with this issue - and I welcome any ideas to solve it.
I'm in the need for help/advices - because my amp is behaving strangely.
The issue i related to the power - since I can not turn on or off the amp with the on/off push button.
The second that the power cord is plugged in - the display show; volume level, and source - but only in half a second - but then nothing happens - and the unit can not be operated. This happens no matter if the on/off button is set to on or off.
A few times - I managed to turn the unit on (when plugging in/out the power cord several times).
When the power remains long if not to turn the unit on - it plays nicely.
But - another strange thing is - that in these situations - I can not turn off the power using the on/off button. When switched off - the unit just keeps playing.
At first I thought this was an issue regarding the on/off switch it self - but now I'm not sure anymore.
When playing - the unit can suddenly close down - and afterwards I'm back to not being able to turn it on again.
I hope that some of you are familiar with this issue - and I welcome any ideas to solve it.
The front panel controls on the Alpha 10 are operated via a microprocessor in order that they can also be operated with a remote control device. So, it's likely that there is problem with the microprocessor if the front panel controls are not operating or erratic. Do you have a remote control to check that there are problems with it too? My first suggestion is to take it to a service person or contact the distributor for suggestions as to who may be able to check the unit properly before quoting any repairs, if necessary. This is not a simple DIY job and unless you know a bit about microprocessors, I'd leave it to someone who does.
Others more familiar with this amp. and microprocessors generally, may be able to help by pinpointing the problem with your checks and tests. First though, read the Power circuit description (p#3) of the manual, to get an idea of what should be happening when powering up/down. Then check the fault-finding diagram.
The manual is available as a free download after signing up: Arcam Alpha 10 - Manual - Stereo Integrated Amplifier - HiFi Engine
Others more familiar with this amp. and microprocessors generally, may be able to help by pinpointing the problem with your checks and tests. First though, read the Power circuit description (p#3) of the manual, to get an idea of what should be happening when powering up/down. Then check the fault-finding diagram.
The manual is available as a free download after signing up: Arcam Alpha 10 - Manual - Stereo Integrated Amplifier - HiFi Engine
Thanks.
I agree that there could be several reasons for my amps issue.
I have been studying the service manual - and that got me even more confused because according to the manual - it should be at least 3 seconds before any security circuits were closing down the unit. But my unit closes in less than 1 second. And it happens without any warnings. (No flashing red light / no messages in display etc.).
I hope this is not a micro processor issue - because if it is I think I'm lost.
But due to the amps behaviour - compared to how it should be - I'm afraid that the issue probably could very well be due to the micro processor.
However I have seen a couple of cases - were people have reported that they could not power on their amps (with micro processors) - and that they had solved it by only replacing a capacitor. This was not Arcam though.
But my Arcam also contains a few capacitors - so I have a little hope - that it might be enough to replace some of those (or all capacitors).
But if replacements of capacitors (and simple components) is not solving anything - I simply just don't know how to decide if a micro processor is faulty - or for that matter decide if one of the transistors could be faulty.
Or perhaps it could also be the front panel circuit board - as RM has mentioned.
I need to know how it is possible to find out if it is a micro processor issue or not. It would also be a great help for me to know if some of this forums users - have seen the same behaviour regarding arcam amps - and then also what had caused it.
BR/Behsen
I agree that there could be several reasons for my amps issue.
I have been studying the service manual - and that got me even more confused because according to the manual - it should be at least 3 seconds before any security circuits were closing down the unit. But my unit closes in less than 1 second. And it happens without any warnings. (No flashing red light / no messages in display etc.).
I hope this is not a micro processor issue - because if it is I think I'm lost.
But due to the amps behaviour - compared to how it should be - I'm afraid that the issue probably could very well be due to the micro processor.
However I have seen a couple of cases - were people have reported that they could not power on their amps (with micro processors) - and that they had solved it by only replacing a capacitor. This was not Arcam though.
But my Arcam also contains a few capacitors - so I have a little hope - that it might be enough to replace some of those (or all capacitors).
But if replacements of capacitors (and simple components) is not solving anything - I simply just don't know how to decide if a micro processor is faulty - or for that matter decide if one of the transistors could be faulty.
Or perhaps it could also be the front panel circuit board - as RM has mentioned.
I need to know how it is possible to find out if it is a micro processor issue or not. It would also be a great help for me to know if some of this forums users - have seen the same behaviour regarding arcam amps - and then also what had caused it.
BR/Behsen
It is X1 in the parts list on page 12. Schematic pages 16 and 18 both have a ceramic resonator in their respective clock circuits. Mouser stocks 4 MHz resonators: ceramic resonator 4 MHz Through Hole Resonators | Mouser
If you have a scope you can probe the resonator pins to see if the clock is running in both circuits. Otherwise since the resonators are cheap buy some extras so you have spares if needed and change both of them in the amplifier.
If you have a scope you can probe the resonator pins to see if the clock is running in both circuits. Otherwise since the resonators are cheap buy some extras so you have spares if needed and change both of them in the amplifier.
Thanks jaycee, RM and Bill
Those resonators are so cheap that a replacement is worth to try no matter what - so I'm going to order a few of them.
But in the Weekend I'm also going to test with a scope - though that will be new to me since I'm not familiar with scopes - so I don't know if I will get a reliable result using it.
RM I might get back to you if I'm going to need a board replacement later. But it might take som time before I have figured that out - but thanks for your offer anyhow.
BR Benny
Those resonators are so cheap that a replacement is worth to try no matter what - so I'm going to order a few of them.
But in the Weekend I'm also going to test with a scope - though that will be new to me since I'm not familiar with scopes - so I don't know if I will get a reliable result using it.
RM I might get back to you if I'm going to need a board replacement later. But it might take som time before I have figured that out - but thanks for your offer anyhow.
BR Benny
Follow up
Now I have replaced the resonator - (thanks jaycee and Bill) - and things looks a lot better than before - although the issue is not solved completely yet.
I could only find one resonator (the service manual is a mix of alpha 10 amp and power amp - and I think the second one that Bill did mention is in the power amp).
At first after replacing the resonator - Alpha 10 powered up when the power cable was plugged into the power socket - and everything seemed ok.
But then after I unplugged it again - it would not power on before after a couple of minutes. During that time I unplugged an plugged in again a couple of times.
After this it was ok for a couple of hours - until I wanted to switch it off again.
I turned it off (power switch) - but it remained on - until I used the remote from my tv-set. When turned off by the remote it closed down (not to standby mode but to power off mode).
Today i could not turn it on again. Power switch set to on - but nothing happened.
Then i used a remote to switch between the sources - and after 1-2 minutes the unit finally turned on.
Any ideas? Could it be a mechanical problem with the power switch itself - or should I be looking for something else.
PS: A weird thing happened when I took a photo using flash. the flash light turned off the unit. Not the infra-read focus light - but the white flash light. After that the unit reported an error (red lamp flashing when powered on again). But after switching off and on using the switch button - the red light was gone - and the unit could be operated again.
Now I have replaced the resonator - (thanks jaycee and Bill) - and things looks a lot better than before - although the issue is not solved completely yet.
I could only find one resonator (the service manual is a mix of alpha 10 amp and power amp - and I think the second one that Bill did mention is in the power amp).
At first after replacing the resonator - Alpha 10 powered up when the power cable was plugged into the power socket - and everything seemed ok.
But then after I unplugged it again - it would not power on before after a couple of minutes. During that time I unplugged an plugged in again a couple of times.
After this it was ok for a couple of hours - until I wanted to switch it off again.
I turned it off (power switch) - but it remained on - until I used the remote from my tv-set. When turned off by the remote it closed down (not to standby mode but to power off mode).
Today i could not turn it on again. Power switch set to on - but nothing happened.
Then i used a remote to switch between the sources - and after 1-2 minutes the unit finally turned on.
Any ideas? Could it be a mechanical problem with the power switch itself - or should I be looking for something else.
PS: A weird thing happened when I took a photo using flash. the flash light turned off the unit. Not the infra-read focus light - but the white flash light. After that the unit reported an error (red lamp flashing when powered on again). But after switching off and on using the switch button - the red light was gone - and the unit could be operated again.
I love Arcam. If you think they sound poor what are you comparing them with? I think the Alpha 8, 9 and 10 was their best work. And you still see plenty of them running today 23 years later. All jap caps inside, mostly Rubycon...Just how much do you like this thing?
Asking as Arcams (in MY experience) are fairly poor sounding contraptions.
One can do significantly better for Far less coin. Just My 2 pfennings
The Alpha 10 had all the power of the biggest NADs with better reliability. You can pick up a 10 for £300. Show me anything NEW out there today at say £800 that is better. There isn't anything. It's nearly all Chinese crap with crap Chinese capacitors.
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My next guess would be the IR receiver is faulty, and it's generating spurious signals which are confusing the microcontroller. A simple test would be to remove it, or as the schematic suggests, cut LK1 on the front panel PCB.
Actually... thinking about it, do you have any compact flourescent lamps in your room ? It is possible these are generating interference that the IR sensor picks up. Very common problem with some TV's, and I see no reason it couldnt affect the A10
Actually... thinking about it, do you have any compact flourescent lamps in your room ? It is possible these are generating interference that the IR sensor picks up. Very common problem with some TV's, and I see no reason it couldnt affect the A10
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Yes you might be right again. And it might be worth to check the IR - but I think there might be something more than the IR.
Again today I pushed in the power button - and nothing happened. The unit did not even show that it was in standby mode.
Same as yesterday I then used the remote - but the unit did not turn off until I had switched several times between "on" - and all off the sources.
When it finally kicked in - there was no sound in my loudspeakers.
However when I pushed the "control" button on the unit the sound came on immediately.
Again today I pushed in the power button - and nothing happened. The unit did not even show that it was in standby mode.
Same as yesterday I then used the remote - but the unit did not turn off until I had switched several times between "on" - and all off the sources.
When it finally kicked in - there was no sound in my loudspeakers.
However when I pushed the "control" button on the unit the sound came on immediately.
'seems to me that if you do have function occasionally, the supply voltage to the control logic or any associated cable connectors may have bad contacts. It could even be down to dried out capacitors resulting in an intermittent or noisy supply. 'Easy enough to check the 5V logic supply to the relevant devices with a DVM.
There's a comprehensive service manual here, a free download after you register. BTW, it is a problem amp, witnessed by the number of threads and faults here, other forums and my own limited repair experience on them.
There's a comprehensive service manual here, a free download after you register. BTW, it is a problem amp, witnessed by the number of threads and faults here, other forums and my own limited repair experience on them.
Thanks Ian and Jaycee - I will do some measurements in the coming Weekend.
Today I discovered this - when I came home from work:
Pushed in the power button -and as before nothing happened (no red or green light).
But this time I did nothing further because I wanted to see if something happened later if I did not switch power off again.
After 10-15 minutes it finally switched on by itself (green light - and source selected was now shown) - and it worked flawlessly all evening.
Does this tell you something?
Today I discovered this - when I came home from work:
Pushed in the power button -and as before nothing happened (no red or green light).
But this time I did nothing further because I wanted to see if something happened later if I did not switch power off again.
After 10-15 minutes it finally switched on by itself (green light - and source selected was now shown) - and it worked flawlessly all evening.
Does this tell you something?
Yes I agree. I will check the the regulators now.
If I don't find anything I'm considering to keep it connected to power socket all the time.
The reason is that when I first has managed to power it on - it works rather great.
Do you think that it is safe to leave it in stand by mode all the time - when it is not used?
I'm asking because after all it has a fult - but I guess it should be ok to leave it in stand by instead of unplugging it.
If I don't find anything I'm considering to keep it connected to power socket all the time.
The reason is that when I first has managed to power it on - it works rather great.
Do you think that it is safe to leave it in stand by mode all the time - when it is not used?
I'm asking because after all it has a fult - but I guess it should be ok to leave it in stand by instead of unplugging it.
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