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Newbie needs advice on Arcam Delta 290

Discussion in 'Arcam Owners' Forum' started by portyporty, Dec 30, 2004.

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  1. portyporty

    portyporty
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    This amp has had a dodgy mode selector switch almost from the time I bought it new. (viewed from the front, it's the first control on the left side)


    The sound output will be fine for some time, but will suddenly become patchy and fragmented. Rotating the switch through it's full range several times always fixes it. We only ever use the CD and AV positions of the switch.

    I'm no electronics boffin, but from the symptoms it sounded to me like the result of a dirty rotary multi-pole switch, so finally, after umpteen years of putting up with it, I thought I'd see if I could do something about it.

    However, after opening up the unit, the switch is obviously somewhat more sophisticated than a simple rotary type, and I'm not sure how to proceed further.

    The switch consists of a small oblong box, about 25mm x 35mm square and about 55mm in length. The aluminium case is marked 'ALPS' and 'Japan' and also has a small circular appendage about 20mm in diameter, fixed to one side near the front.

    The whole unit appears to be soldered into the motherboard at several points, so it doesn't look as though I can easily remove it for cleaning, given my level of inexpertise.

    Can someone suggest a fix for the problem? As I can't remove it, I wondered if it might be productive if I was to turn the whole amp upside down and spray some CRC inside the switch casing.

    Otherwise I can't see what else I can easily do, short of simply putting up with this intermittent problem, or replacing the amp.

    I did email Arcam about the problem a couple of years back, but had no response at all.

    Advice would be much appreciated.

    PS. There seem to be several nylon cogs inside the switch case, though they don't rotate when the switch axle is turned. However, the switch seems to work OK, as it selects between modes without problem - it's simply that occasionally, after sitting in one position for several hours, some component of the switch ceases to properly conduct a signal until it's moved several times.

    Thanks.
     
  2. keiths

    keiths
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    Hi

    I used to own a Delta 290 and had exactly the same problem. The switch is more complicated than normal because it is motor-driven (so that source selection can be done by remote control).

    I did exactly what you suggest - sprayed some switch cleaner into the switch and rotated it a few times to wipe the contacts. Only relieved the problem for a few days at a time though.

    Looks like you will need to consider getting the switch replaced.
     
  3. MrTubThumper

    MrTubThumper
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    Hi, this is all new to me and it look pretty good!
    I used to have a 290 and had the same trouble, much to my frustration I found out that Arcam can no longer source the part and no one could therefore repair it!

    I would suggest using the tape loop inputs, therefore bypassing the switch, as frustrating as it is that's all you can do. I ended up selling mine on ebay to someone who had one but had a different problem, he used mine for parts!
    Hope this helps

    Paul
     
  4. portyporty

    portyporty
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    Thanks for your input, keiths and noodlestick. It didn't occur to me that the problem could have affected anyone else.

    Obviously, Arcam have been on the back foot over what turned out to be, at the very least, a troublesome part, possibly even faulty, which probably explains why they didn't respond to my original enquiry.

    Well, it seems that it's up to me to either fix it or put up with it, so I might as well have a go at a repair. Does anyone know why the box surrounding this switch is so robust? Is it a shield?

    I mean, my first thought would be to chop off the top of the box (where the label 'ALPS, Japan' is imprinted) so that I can get at the switch innards. If I mask off the switch's surroundings, I shouldn't get too many fragments of alloy into places I can't reach.

    It's interesting to read keiths's comment that this switch can be remotely operated. I have a remote but have never used it for anything else except volume adjustment. It seems likely that the switch could have been a lot simpler and less troublesome if Arcam had opted for a manual mode changer.

    Perhaps I ought to test it's remote operation. Does anyone know if it'll cause a problem if I power-up the amp with nothing else attached?

    As I said, I'm no boffin when it comes to this sort of electronics :rolleyes:
     
  5. Timmy C

    Timmy C
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    I too had the same problem with my 290. I replaced after a few years with a 9c pre amp which developed the same fault. Now moved onto a C30 but if it happens again I'll be selling my entire Arcam set up!
     
  6. portyporty

    portyporty
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    15th July 2007:
    I've had a lot of requests for info about this problem, so I've just now edited both this final post, and the photo\doc that I created in case anyone wanted it. Here goes with the edited version:
    -------------------
    <I managed to find a solution to my problem with the 290 mode selector switch, so I'll post a description of what I did, in case it helps anyone else.

    Arcam's Delta 290 mode selector switch seems to get dirty after several years of use, causing intermittent and sometimes muted sound transmission. Unfortunately, the Japanese &#8216;Alps' switch that Arcam used (in my machine, anyway), has a very solid housing, which prevents easy access to the enclosed rotary multi-pole selectors.

    So, accessing the switch contacts was the first, and major problem. The second task, cleaning the contacts, was relatively easy, once I could reach them.

    The mode selector contacts are contained inside an oblong stainless steel box, which is soldered onto the motherboard. I'd guess the gauge of the metal to be at least 24g, maybe heavier.

    The initial problem was, how to open the switch housing without using undue pressure, which could cause damage to the main board or other nearby components? My first idea was to line-drill a large hole in the top of the housing, although this would probably have been fairly difficult, given that the material used was stainless steel, and not aluminium as I'd first thought.

    The ideal tool turned out to be a Ryobi engraving machine. Included in its accessory kit was a small cut-off wheel, about 20mm in diameter and 1mm thick. This proved to be ideal for the job; the tool revs at 16,000 rpm, resulting in a very fast cutting edge speed.

    To avoid a complex clean-up job, I swathed the rest of the amplifier in an old sheet, leaving just the switch box exposed. After that it was just a matter of grinding away. In the finish I cut away about 2\3 of the body of the box, simply folding back some of the metal with pliers to avoid more cutting than necessary, which exposed most of the rotary selectors. Turned out that there were three rotary selectors in line, inside the box, spaced about 20mm apart.

    I'd fully exposed two of the three, but the third was near the amp's front panel, and seemed to be tied up with the wireless\infra-red remote-control gear of the switch, so I left it alone, hoping that cleaning just the two selectors that I could reach would be sufficient. This has proved to be the case.

    During the cutting work, quite a bit of fine dust got through the sheet; I should have used plastic instead of polycotton to swathe the motherboard. Anyway, I was able to clean out the amp with a vacuum cleaner, a soft brush and a blower, so all that was left was to clean the two rotary selectors, which are basically square panels about 3-4mm thick, soldered into the motherboard at a right angle and connected to each other, and the knob, by a square drive shaft about 5mm thick (see photos in doc).

    I figured that the best way to clean the selectors would be to somehow immerse them in a liquid cleaner, so I made a bath out of the lid of a roll-on deodorant dispenser. The lid (see photo) resembles half an eggshell and is about 45mm in diameter. I cut a slot about 15mm deep in one side to fit over the square shaft that connects and rotates the selectors.

    I turned the amp upside down and slid it out over the edge of my workbench until it was just teetering, with about half its length still in contact with the bench surface, then weighted it down with a pile of books to keep it stable.

    Then I sat on the floor underneath the overhanging amp, filled my lid with meths to the level of the slot in the side, then applied the cup up and over the selectors until it fetched up against the motherboard.

    The two selectors were now hanging downwards and immersed about 10mm into the meths bath. After that I just kept rotating the selector knob backwards and forwards for about 5 minutes, until I guessed that the selector contacts had received a reasonable cleaning. (A little meths may spill out, so beware naked flames)

    I reassembled the amp and it worked fine, with no more of the patchy sound problem. Someone here suggested using a special contact cleaner, which apparently removes carbon buildup, but I don't know what that is or where to get it in NZ.

    It's quite possible that methylated spirits might not be the best cleaning medium, but it was on hand and I thought it was preferable to turpentine or CRC-type aerosols, as it leaves no oily residue. Anyway, it seems to have worked.

    I took a few digital pics of the operation, and created a Word doc, so if anyone wants a copy, post me at computerguys@xtra.co.nz > (end of edited post thread)

    Footnote: The switch stayed clean for about 2 &#189; years &#8211; I did it again in May 2007.
     
  7. Stevepar

    Stevepar
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    Hi Everyone,

    I have the very same problem with the mode/listen selector switch, and have found a fix provided you dont use the record selector switch for it's very purpose! Love this amp and cant afford a suitable replacement, so heres what we did :thumbsup:

    I'm no electronics expert and delivered the amp to my friend Guillaume Lemaire owner of Croak Audio Exploration in South Africa for this fix. Unfortunately I did not make notes or take pictures of the last few bits but an explanation of what we did follows:

    First the output from the listen selector switch was traced and its connection with the volume control interrupted by cutting tracks carefully, then the outputs from the record switch were traced and then bridged on to the input to the volume control.

    So I'm basically using the record selector switch to change inputs, and since it was never used for the purpose of recording, it's good as new and sounds brilliant!

    Please note that the photo is of attempt one and has an error. I will open the amp and take more images if anyone needs them!

    Attached is a page from the service manual showing the selector diagrams.

    [​IMG]
     

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  8. buddyevans

    buddyevans
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    steve
    that's a very good idea. Its a great amp but I think everyone with one has the same problem. I'll give this a go.
     
  9. rubberdog

    rubberdog
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    Thanks for the info, is there any chance you could send me the photos? thanks
     
  10. Timmy C

    Timmy C
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    There's now a chap on ebay offering to fix this problem for £38 plus postage. I don't know anything more than that but it might be useful to some.
     
  11. R1150GS

    R1150GS
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    My old delta 290 suffered the same problem.

    It really isn't that hard to de-solder the selector unit and remove it from the P.C.B. Just buy or borrow a decent soldering iron and a de-solder sucker.

    I removed the selector unit from the board then dismantled it (taking care to note the position and orientation of the selector discs). Then I cleaned up all the contact surfaces with 1000 weight wet&dry paper and alcohol. Re-assembled it and soldered it back into place.

    I haven't had any problems with it for a couple of years. It is still a great sounding amp.
     
  12. JaySteel

    JaySteel
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    Hi everyone. My trusty old Arcam Delta 290 now has this notorious fault. I wish to keep this amp going as I love the sound it produces when partnered with my 290P and run through my old Mission 753 speakers.

    Timmy C - I've done a search on Ebay for the guy offering this repair service but unfortunately I'm not getting any results. Do you have any more details for him please?

    Does anyone else know of a reliable place that can carry out this repair service for a sensible price? I have no technical abilities myself and the last time I tried to carry out my own repairs was a complete disaster so I will definitely be leaving this to a professional.

    Thanks for your help in advance.

    Jason
     
  13. Timmy C

    Timmy C
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    The guy is back on ebay now...or it could be another guy offering the same work. His username is
    mr_diagonal. If you search completed listings at the moment you can see what he offers but he doesn't seem to have one active at the moment.
     
  14. JaySteel

    JaySteel
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    Thanks Tim. I did manage to find the guy and he does still do this work.

    Jason
     
    Last edited: Jul 10, 2012

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