Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Digital Source Digital Players and Recorders: CD , SACD , Tape, Memory Card, etc.

Arcam Alpha 8 CD problem
Arcam Alpha 8 CD problem
Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 9th January 2015, 10:21 PM   #1
937carrera is offline 937carrera  United Kingdom
diyAudio Member
 
Join Date: Jan 2015
Default Arcam Alpha 8 CD problem

New member and first post is looking for help, sorry

I decided to try and use my Alpha 8 CD player yesterday, after quite some time. Last time I tried to use it, it seemed to take some time to recognise discs and the it would frequently skip portions of various CD's, so I left it alone.

Today I decided to investigate so removed the top cover to observe what happens when a disc is inserted. It goes through the following process

Drawer closes
Transport moves up
Laser moves to centre of disc
There is a repeated whirring / slowdown sound which changes with the speed of the disc. The disc does not get up to full speed
I have not been able to observe the ( red ? ) laser

I have played about with x-box transports and tweaked laser output in the past, have access to a multimeter, have done component level soldering including IC (but not GBA), have no scope and a basic / rudimentary understanding of how the electronics work.

It seems to me that the laser mechanism may need replacing, but rather than go out and just buy one, it would be great if you could confirm my diagnosis, offer suggestions for other checks to perform and warn me of any installation / alignment issues I may have to face.

The player is fully dismantled and I did find one small piece of white plastic loose upon dissassembly. I have not yet identified exactly where it has come from but there are a number of similar pieces elsewhere on the transport. In the picture below it is placed on the black part of the transport Is this important or not ?



Click the image to open in full size.
  Reply With Quote
Old 10th January 2015, 10:55 AM   #2
Mooly is offline Mooly  United Kingdom
diyAudio Moderator
 
Mooly's Avatar
 
Join Date: Sep 2007
Arcam Alpha 8 CD problem
Have you cleaned the lens thoroughly ?

It could well be the pickup at fault but I also seem to recall many Arcam products suffer from dried out electrolytics in the power supply. Might be worth checking.
  Reply With Quote
Old 10th January 2015, 10:06 PM   #3
937carrera is offline 937carrera  United Kingdom
diyAudio Member
 
Join Date: Jan 2015
Thanks for the thoughts. I'm pretty sure the lens is clean as I have a large bottle of IPA but I will recheck that.

This one has already had some of the caps replaced as I had a hum/buzzing sound about 5 years ago. The caps that had failed were located under the DAC if I recall quickly.

Is it possible to test the voltage that feeds the laser ?
  Reply With Quote
Old 11th January 2015, 07:30 AM   #4
Mooly is offline Mooly  United Kingdom
diyAudio Moderator
 
Mooly's Avatar
 
Join Date: Sep 2007
Arcam Alpha 8 CD problem
The laser will be fed from the 5 volt supply and a scope is always the best check because it shows noise and ripple as well as the voltage. A meter may well show a correct 5 volts even in the presence of ripple.

Measuring the voltage to the laser wont reveal much (unless there is a gross problem) because the laser is current fed and incredibly tightly controlled with an optical feedback loop within the pickup itself.

You need to confirm all the rails in the player are good. A meter will show obvious issues but if non are found then without a scope check it still doesn't mean they are actually OK.

The fact its had cap issues would be a good reason to suspect there could be similar issues now or a missed cap from earlier.
  Reply With Quote
Old 11th January 2015, 07:25 PM   #5
Willi Studer is offline Willi Studer  Serbia
diyAudio Member
 
Join Date: Jan 2008
I would leave it powered on overnight and see what happens in the morning. You mention that you haven't used it for some time and current flow may help restore some faulty contact, cold solder joint or condition a faulty capacitor. If you get it up and running, that means the laser pickup and transport are OK but the player requires some overhauling.
  Reply With Quote
Old 11th January 2015, 09:01 PM   #6
937carrera is offline 937carrera  United Kingdom
diyAudio Member
 
Join Date: Jan 2015
I have been able to spend a little time on the player today.

After spending a little time studying the service manual to locate test points I decided to reassemble the player and see if it worked after cleaning the lens.

It did, well sort of
  • The first CD played fine (and sounded great)
  • The second CD played fine, then it skipped on track 6. I cleaned the CD and it played without issue
  • I then put a new CD is (Xmas present). It struggled to recognise the CD, did the laser focussing many times and when it did eventually play it skipped tracks.
  • I put the CD into a DVD player and it played fine, so it doesn't appear to be a faulty CD
  • After a couple of hours I removed the CD from the DVD player and put it in the Arcam which recognised and played it fine.
I looked at the laser when closing the tray with no disc inserted. The red laser was there but looked very feeble to me, more like a glow than a "dangerous" laser.

Although the CD hasn't been played for sometime I wouldn't say that the electronics were generally cool because it resides just above my amp, which might be a problem (and am now going to get some sorbothane feet to act as spacers to increase airflow). Nonetheless it is always possible that the process of re-connecting the cables may also have restored an oxidised contact.

Should my next steps be to complete the work on ascertaining / checking the test points for the different supplies with my multimeter, or does the additional information above point in a different direction ?

Many thanks for all the help so far.
  Reply With Quote
Old 12th January 2015, 06:57 AM   #7
Mooly is offline Mooly  United Kingdom
diyAudio Moderator
 
Mooly's Avatar
 
Join Date: Sep 2007
Arcam Alpha 8 CD problem
The laser light is near infra red which is why it looks feeble... it is our eyes that can't see it properly.

Most likely issues are caps... I can't specifically say which they would be, just that Arcam products have a certain reputation... and perhaps poor joints but they would typically be around regulators and other "non standard" parts.

You really do need to use an oscilloscope on this... that is the correct diagnostic tool. We are just making educated guesses at the moment.
  Reply With Quote
Old 3rd October 2017, 01:21 PM   #8
937carrera is offline 937carrera  United Kingdom
diyAudio Member
 
Join Date: Jan 2015
Re-awakening this as I now have some time again to try and fix it again. The symptoms now are that the CD tray would close but the spindle motor would not spin and there was no reading of the TOC.


I stripped the transport unit down last night to get access to the motors and switches.


Using some AAA batteries I powered the sled motor and the spindle motor.. Both worked, the spindle motor was a little hesitant to start, but that was quite possibly the contact from the wires onto the connections.


I also tested the two micro switches, they tested OK.


I partly reassembled the player, applied power and on the second / third attempt the spindle motor engaged but stalled. I gave the CD a little encouragement and it spun up and played a CD. Apparently good news. It then consistently made the high pitched "chirruping" as it read the CD TOC


Today I stripped down and reassembled the player again (not the transport) and have tested it again. It is now back to not spinning the disc.


Can anyone point me more precisely in the area I need to be looking at. I can't see a way to test the operation of the micros switches when the CD is loaded...... unless anyone knows better.


Thanks in advance for any help
  Reply With Quote
Old 3rd October 2017, 06:59 PM   #9
Mooly is offline Mooly  United Kingdom
diyAudio Moderator
 
Mooly's Avatar
 
Join Date: Sep 2007
Arcam Alpha 8 CD problem
The same advice still holds... you need to be using an oscilloscope to see what is going on.

The spindle motor will not spin until after focus is found on the stationary disc.

You mention it will intermittently play. This is where you need to look at the signal from the pickup to confirm the amplitude and overall Q (or quality) factor is good.

And again, supplies all have to be checked for correct voltage and the absence of ripple.
  Reply With Quote
Old 5th October 2017, 06:14 PM   #10
937carrera is offline 937carrera  United Kingdom
diyAudio Member
 
Join Date: Jan 2015
Thanks Mooley,

The problem isn't intermittent anymore, which is generally better for diagnosis. It didn't work at all, I stripped the transport, partly reassembled and it did play again without skipping. Did a final reassembly and it didn't work again.

I was hoping when I posted that the lack of spinning the spindle would help point in a specific direction. I'm usually pretty good at diagnosing / repairing things, but on this occasion it looks like I'm a bit short of equipment....namely access to an oscilloscope...... and even if I did then the knowledge to know how to use it properly.

I doubt it is work buying a s/h one for this job, so can anyone recommend someone who could carry out a proper diagnosis & repair ? (I'm located in North Yorkshire in case there is someone local)
  Reply With Quote

Reply


Arcam Alpha 8 CD problemHide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Arcam Alpha 5 CD - playback problem szawszaq Digital Source 4 30th October 2010 10:12 AM
Arcam alpha plus cd player help Scrappydoo Digital Source 29 1st March 2010 07:31 AM
Arcam Alpha 5 CD remote planetbass Digital Source 17 10th December 2009 01:00 AM
Arcam Alpha 5 Plus CD Player. Umberto Digital Source 18 10th October 2009 11:47 AM
Arcam Alpha 5 CD Player paulcurrie Digital Source 0 31st January 2004 12:47 PM


New To Site? Need Help?

All times are GMT. The time now is 09:53 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.79%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio
Wiki