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Thread: Akai GX-635D found

  1. #1
    Join Date: Apr 2013

    Location: Solihull, UK

    Posts: 410
    I'm Bob.

    Default Akai GX-635D found

    After a bit of a search and a few dead ends I finally have an AKAI GX-635D. It’s sonic performance is beyond my expectation, no hiss, wide dynamic range and what goes onto the tape comes out through the speakers. Wasn’t expecting it to be this good.

    But – it does have a couple of issues that I need to fix / have fixed and would welcome some help and guidance.

    1. LH VU meter is intermittently sticky. It’s behaviour is similar to a peak hold meter – except it doesn’t return for sometimes a minute or two. Working below the 0dB level it seems fine but sometimes sticks in the red when things get a bit boisterous. Sometimes stays stuck when the power is switched off.

    2. The capstan motor is noisy. Not audible over the music but when the music stops you can hear it. Sounds like humming and changes tone when the pinch wheel engages. Behaviour is common whether playing forward or reverse.

    3. The tape counter is fine when playing but sometimes goes into a banshee like howl when approaching speed in FF / REW. Sounds like maybe plastic dry running on a shaft?

    The previous owner said it had been “serviced” (whatever that may amount to) 3 months ago. The inside is clean and free from any dust accumulation and from what I’ve seen the linkages look clean and not caked in old lubricant, so some work has been done. The owner also said it had been standing for a while.

    Any ideas?
    Source: Orbe SE / SME IV / Cadenza Bronze
    Source: WD NAS / Cyrus Stream X2 / Chord DAVE
    Source: Oppo UDP-205 (CD/DVD-A/SACD)

    Amplification: Icon Audio PS 3 Sig Phono + Audio Research LS27 + Musical Fidelity A5cr Power Amp
    Loudspeakers: ProAc Response D28
    Cables/stands: Mark Grant G1500HD + Linn K20 + Cat 5e
    Other bits: Okki Nokki keeping things clean

  2. #2
    Join Date: Oct 2012

    Location: The Black Country

    Posts: 6,089
    I'm Alan.

    Default

    Doesn't sound like anything serious with any of the issues.

    I used to have an Akai in my youth, nice machines. Bring it round here and I'll fettle it at no charge.


  3. #3
    Join Date: Apr 2013

    Location: Solihull, UK

    Posts: 410
    I'm Bob.

    Default

    That's an extremely generous offer Alan, even if you can only give me a view.

    PM sent.
    Source: Orbe SE / SME IV / Cadenza Bronze
    Source: WD NAS / Cyrus Stream X2 / Chord DAVE
    Source: Oppo UDP-205 (CD/DVD-A/SACD)

    Amplification: Icon Audio PS 3 Sig Phono + Audio Research LS27 + Musical Fidelity A5cr Power Amp
    Loudspeakers: ProAc Response D28
    Cables/stands: Mark Grant G1500HD + Linn K20 + Cat 5e
    Other bits: Okki Nokki keeping things clean

  4. #4
    Join Date: Aug 2012

    Location: Hartlepool UK

    Posts: 1,640
    I'm Alan.

    Default

    Thats very generous Alan isn't AOS a nice place

    Think Audio Al had one of these decks with similar problems see this thread on tape heads
    http://www.tapeheads.net/showthread.php?t=40907

    Alan
    Turntable - Garrard 401/Jelco 750L/Ortofon Kontrapunkt B, Pioneer PLC 590, Micro Sieki MA505 , Denon DL103R - DIY Paradise Phono stage - Reel 2 Reel Studer A810, Otari MX55,Tascam BR20, Revox A77, B77, PR99, TEAC X1000 & 3440, Digital HTPC / Young Dac - Preamp - DIY B4, 821, Power Amp's DIY Avondale NCC300 Mono Block, Speakers Wilmslow Kit Volt BM220.8 / Scanspeak D2905/9500

  5. #5
    Join Date: Apr 2013

    Location: Solihull, UK

    Posts: 410
    I'm Bob.

    Default

    I read Audio Al's "AKAI GX-635D refurbishment" post on Tapeheads a couple of weeks ago but after the first excellent page drawing me in it seemed to come to an abrupt halt.

    If the rest is out there I'd love to read it - especially as it has added significance for me now. I also read the other GX-635 posts on the site but they were covering specifics that may (or not?) be a bit further down line for this deck. It has to be getting on for 40 years old, is of unknown provenance but is generally in working order - with a few issues that need resolving to bring it back to it's former peak.

    Anyway, here's a gratuitous pic (minus side panels): I hope you'd agree it's worth saving. (Despite the labels the tape on the reels isn't Ampex 406).



    And yes, you do meet the nicest people on AOS.

    Bob

    (Off to see Mr Firebottle this afternoon)
    Source: Orbe SE / SME IV / Cadenza Bronze
    Source: WD NAS / Cyrus Stream X2 / Chord DAVE
    Source: Oppo UDP-205 (CD/DVD-A/SACD)

    Amplification: Icon Audio PS 3 Sig Phono + Audio Research LS27 + Musical Fidelity A5cr Power Amp
    Loudspeakers: ProAc Response D28
    Cables/stands: Mark Grant G1500HD + Linn K20 + Cat 5e
    Other bits: Okki Nokki keeping things clean

  6. #6
    Join Date: Aug 2012

    Location: Hartlepool UK

    Posts: 1,640
    I'm Alan.

    Default

    That looks a beautiful machine Bob
    Nick Adams did some very good service video's on the GX 656D over on Youtube which is simlar

    https://www.youtube.com/watch?v=Bx1e-gFqmx0
    https://www.youtube.com/watch?v=swTw25JmGhI

    Alan
    Turntable - Garrard 401/Jelco 750L/Ortofon Kontrapunkt B, Pioneer PLC 590, Micro Sieki MA505 , Denon DL103R - DIY Paradise Phono stage - Reel 2 Reel Studer A810, Otari MX55,Tascam BR20, Revox A77, B77, PR99, TEAC X1000 & 3440, Digital HTPC / Young Dac - Preamp - DIY B4, 821, Power Amp's DIY Avondale NCC300 Mono Block, Speakers Wilmslow Kit Volt BM220.8 / Scanspeak D2905/9500

  7. #7
    Join Date: Nov 2016

    Location: UK London

    Posts: 236
    I'm Chris.

    Default

    That is one lovely looking piece of kit, but I am not jealous, well not much anyway
    Turntable : Project 2 Xperience Tone Arm & Cartridge : Project 9c Ortofon 2M Blue Phono Stage : Project Phono Box SE II Digital Source :Primare CD21 Integrated Amp : Primare I30 Speakers : ProAc 110 Headphones : Beyerdynamic DT770 Pro

    Revox A77 MK IV 2 track 15 & 7 1/2 IPS
    TEAC A-3300SX 4 track 7 1/2 & 3 3/4 IPS
    Akai 4000DS MkII

  8. #8
    Join Date: Apr 2013

    Location: Solihull, UK

    Posts: 410
    I'm Bob.

    Default

    Just wanted to say a huge thank you to Alan (Firebottle) for the time he made available to me this afternoon.

    Fixed a few things.............
    Learned a lot.....................
    Drank a little coffee............
    Listened to some music......

    And I've moved a little closer to getting this tapedeck where it needs to be. There aren't too many ways to better enjoy an afternoon.

    My thanks.
    Source: Orbe SE / SME IV / Cadenza Bronze
    Source: WD NAS / Cyrus Stream X2 / Chord DAVE
    Source: Oppo UDP-205 (CD/DVD-A/SACD)

    Amplification: Icon Audio PS 3 Sig Phono + Audio Research LS27 + Musical Fidelity A5cr Power Amp
    Loudspeakers: ProAc Response D28
    Cables/stands: Mark Grant G1500HD + Linn K20 + Cat 5e
    Other bits: Okki Nokki keeping things clean

  9. #9
    Join Date: Nov 2016

    Location: UK London

    Posts: 236
    I'm Chris.

    Default

    Quote Originally Posted by bob4333 View Post
    Just wanted to say a huge thank you to Alan (Firebottle) for the time he made available to me this afternoon.

    Fixed a few things.............
    Learned a lot.....................
    Drank a little coffee............
    Listened to some music......

    And I've moved a little closer to getting this tapedeck where it needs to be. There aren't too many ways to better enjoy an afternoon.

    My thanks.
    Great stuff, can I ask what was fixed ?
    Turntable : Project 2 Xperience Tone Arm & Cartridge : Project 9c Ortofon 2M Blue Phono Stage : Project Phono Box SE II Digital Source :Primare CD21 Integrated Amp : Primare I30 Speakers : ProAc 110 Headphones : Beyerdynamic DT770 Pro

    Revox A77 MK IV 2 track 15 & 7 1/2 IPS
    TEAC A-3300SX 4 track 7 1/2 & 3 3/4 IPS
    Akai 4000DS MkII

  10. #10
    Join Date: Apr 2013

    Location: Solihull, UK

    Posts: 410
    I'm Bob.

    Default

    Sure.

    The VU meter came apart, was given a mechanical work through by Alan and reassembled. During the process I'm also pretty sure I saw a small piece of debris dislodged from inside the casing, so maybe it was causing a restriction in not allowing the meter to return. Makes sense. Seems fine now. And I'm also now aware of how to get at the festoon lamps if they fail.

    Good news and bad news on the noisy capstan motor. Turns out it's not the motor but a noisy transformer that's causing the irritation. Luckily it's not audible over the music but something I'd like to find a fix for. Anyone have a 240v GX 635D transformer they'd like to part with? No, didn't think so. I'll keep looking and thinking on this one.

    I think I may have fixed the tape counter noise the day before I went to see Alan. It definitely sounded like a plastic "gear on gear" clattering racket. Being careful not to overdo it I'd applied a very small amount of Vaseline on the end of a cocktail stick to the parts of the gearing that would be likely to run at high speed on FF and REW (really the gears that spin on the seconds counters). Had this not have been successful Alan had a spray can of a more specialist lubricant that he would have applied. Have to see how it goes but so far, so good.

    I have to keep reminding myself that this is nearly 40 years old and represents thinking and manufacturing from a different age. It's also been goodness knows where in it's life but doesn't look as though it's suffered at the hands of bodgers. It's not perfect and there are probably a few other things to sort out (I don't fully trust the logic controls when anything high speed is involved, so I go from REW to STOP to PLAY rather than as AKAI say "DIRECT FUNCTION CHANGE CONTROL............ The necessity of depressing the Stop Button prior to changing modes is eliminated". That's a refinement for another day as it doesn't stop the deck being used - I just need to be mindful when in use.

    So yes, making progress on something I find interesting.
    Last edited by bob4333; 20-06-2017 at 09:18.
    Source: Orbe SE / SME IV / Cadenza Bronze
    Source: WD NAS / Cyrus Stream X2 / Chord DAVE
    Source: Oppo UDP-205 (CD/DVD-A/SACD)

    Amplification: Icon Audio PS 3 Sig Phono + Audio Research LS27 + Musical Fidelity A5cr Power Amp
    Loudspeakers: ProAc Response D28
    Cables/stands: Mark Grant G1500HD + Linn K20 + Cat 5e
    Other bits: Okki Nokki keeping things clean

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