Hi,
My Arcam Alpha 10 amp is going into protection mode sometimes (red flashing light) i can play it for hours sometimes with no problem and other times i switch it on and it goes into protection after playing music for sometimes 10 mins, 30mins etc, no exact timing to it. Any ideas/help on this matter would be great
My Arcam Alpha 10 amp is going into protection mode sometimes (red flashing light) i can play it for hours sometimes with no problem and other times i switch it on and it goes into protection after playing music for sometimes 10 mins, 30mins etc, no exact timing to it. Any ideas/help on this matter would be great
Protection mode and virtually everything else is managed by a microprocessor in this model. Given the various faults reported here and elsewhere about Alpha 10, I wouldn't discount the microprocessor's clock or its various sensing circuits as the source of random events like protection glitches, assuming there really is nothing else going on at the time that is likely to trigger them. Have a look at the descriptions of how it should work and some ways to check protection mode, in the service manual.
Arcam Alpha 10 Stereo Integrated Amplifier Manual | HiFi Engine (free after registration)
Arcam Alpha 10 Stereo Integrated Amplifier Manual | HiFi Engine (free after registration)
Hi Ian, thanks for the speedy response - do you know if this is an easy fix - from all the posts I’ve read it seems complicated with this model. Cheers
Unfortunately, you can't proceed with a fix until the suspect component(s) or perhaps just their soldering is proven to be the cause. If a microprocessor clock is unstable, weak etc. it will often show as strange display errors. You need to take careful note of what the display may tell you according to the manual, assuming that is clear enough, as some authors use a technical style which may seem nonsense to non-techs. In this case, I find it easy to read but then, I've been a tech of a sort too.
A common processor fault is often a duff ceramic resonator which is a low cost, 4MHz oscillator device performing the same duty as a traditional crystal frequency reference device. In any case, all digital processors need such a stable clock device to even operate so if the display is stable, it should be fine . Read p3 of the service manual for a run-down on the micro's function and testing etc.
I don't recommend just taking a wild guess at what's actually wrong without checking the symptoms and preparing yourself with good quality, temperature controlled soldering gear. This is to minimise collateral damage to the PCB and other components if and when you dive in and try to replace suspect components. It's certainly a complex machine on several fronts, so all the more important to understand how things work (or not) before trying to fix anything and then with minimal disturbance to other components, PCB pads, tracks etc. It's very hard to correct a damaged PCB and that may be the end of it, considering pro. repair costs.
Normally, a service person would just use an oscilloscope to verify the micro's clock waveform in seconds but DIYs seldom have more than basic hand tools and a DMM. It's not a good way to proceed with an amplifier like this one, which requires some reading, appropriate tools and hands-on expertise.
Other things to consider are that if real, protection faults should be triggered by temperature and current sensing circuits. Again, check the manual for indications then inspect the heatsink temperature sensors, Z11,12 located under the heatsinks. Current limiting and protection is via single transistors Q25,32. I hasten to add that I've only attempted one repair of this model and then needed some suggestions myself on what would be appropriate measurements. I wouldn't be surprised if replacing the resonator was no help either so don't rush out to buy one just yet. The device I'm talking about is shown on the schematic, board and parts list as X1, a common SMD type of 4MHz ceramic resonator.
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A common processor fault is often a duff ceramic resonator which is a low cost, 4MHz oscillator device performing the same duty as a traditional crystal frequency reference device. In any case, all digital processors need such a stable clock device to even operate so if the display is stable, it should be fine . Read p3 of the service manual for a run-down on the micro's function and testing etc.
I don't recommend just taking a wild guess at what's actually wrong without checking the symptoms and preparing yourself with good quality, temperature controlled soldering gear. This is to minimise collateral damage to the PCB and other components if and when you dive in and try to replace suspect components. It's certainly a complex machine on several fronts, so all the more important to understand how things work (or not) before trying to fix anything and then with minimal disturbance to other components, PCB pads, tracks etc. It's very hard to correct a damaged PCB and that may be the end of it, considering pro. repair costs.
Normally, a service person would just use an oscilloscope to verify the micro's clock waveform in seconds but DIYs seldom have more than basic hand tools and a DMM. It's not a good way to proceed with an amplifier like this one, which requires some reading, appropriate tools and hands-on expertise.
Other things to consider are that if real, protection faults should be triggered by temperature and current sensing circuits. Again, check the manual for indications then inspect the heatsink temperature sensors, Z11,12 located under the heatsinks. Current limiting and protection is via single transistors Q25,32. I hasten to add that I've only attempted one repair of this model and then needed some suggestions myself on what would be appropriate measurements. I wouldn't be surprised if replacing the resonator was no help either so don't rush out to buy one just yet. The device I'm talking about is shown on the schematic, board and parts list as X1, a common SMD type of 4MHz ceramic resonator.
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Thanks again for a quick and detailed response - it’s very much appreciated - the display works great with no errors and still brightly lit with no sign of dimness setting in - all function buttons work perfectly as well so maybe that would imply the processor is in good shape? Sounds like from what your saying I should do a few tests myself to try and eliminate certain parts then possibly take it to a pro repair guy if it seems worth it cost wise. I’ve already give it a good clean down inside and cannot see any visible signs of damage.
Hi Ian - just noticed this old post that you contributed to
Arcam Alpha 10 overheating issues
It seems like when i tested my Alpha 10 a few times last night with casing off it was going into to protection mode after around 10-15mins - when i have put case back on this morning it went into protection mode again when i first powered it up but on the second attempt it has now been on for a few hours with no issues - could this mean its something to do with the Z9 being warmed up like the post mentioned in the attached link- if so does this mean i would need to replace the microprocessor? Thanks
Arcam Alpha 10 overheating issues
It seems like when i tested my Alpha 10 a few times last night with casing off it was going into to protection mode after around 10-15mins - when i have put case back on this morning it went into protection mode again when i first powered it up but on the second attempt it has now been on for a few hours with no issues - could this mean its something to do with the Z9 being warmed up like the post mentioned in the attached link- if so does this mean i would need to replace the microprocessor? Thanks
I would not attempt to replace the microprocessor unless it was clearly the problem and I had the skill and tools necessary for the job. As said earlier, don't take guesses - test the effect of temperature change by carefully heating the top of the micro when it fails to start correctly. If you can't stimulate correct operation this way, I would probably replace X1 myself as a relatively simple experiment but leave the micro's replacement to a professional and of course, the micro's are pre-programmed by Arcam so you know where you have to go to get the correct part - if still available.
First though, have you followed the test procedure specified on p4 of the manual? That should answer your question by telling you if the micro has a problem and it's then an opportunity to warm up the chip for checking its intermittent behaviour. You only need to make it finger-hot for this.
First though, have you followed the test procedure specified on p4 of the manual? That should answer your question by telling you if the micro has a problem and it's then an opportunity to warm up the chip for checking its intermittent behaviour. You only need to make it finger-hot for this.