+ Reply to Thread
Page 1 of 2 12 LastLast
Results 1 to 10 of 16

Thread: Studer A810 on the Blink

  1. #1
    Join Date: Aug 2012

    Location: Hartlepool UK

    Posts: 1,640
    I'm Alan.

    Default Studer A810 on the Blink

    Damn my Studer A810 is broken

    The speed started wandering all over the place and the Phase Lock light started blinking and the capstan would not lock even in stop mode

    I removed the Capstan motor and control board and started testing and I have found that one of the Darlington transistors is faulty BU-522, I removed this from the board to confirm it has failed
    When I recapped this board I had also fitted a 47nf cap at C7 which was a mistake, that should have been 470nf which I have now replace I also noted that the heat sink connections for the 2 BU-522 transistors were quite loose so may have been getting hot.
    I have ordered 2 new BU-522 from Little diode and I am hoping this is all that's wrong?.


    20170512_092033 by Alan Towell, on Flickr
    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

  2. #2
    Audio Al is offline Pishanto Specialist & Super-Daftee
    Join Date: May 2012

    Location: Dagenham Essex

    Posts: 11,215
    I'm Allen.

    Default

    Fingers crossed Alan
    [

  3. #3
    Join Date: Mar 2008

    Location: Galashiels

    Posts: 13,669
    I'm inthescottishmafia.

    Default

    Aye hopefully that's the extent of it Alan.
    “Music has always been a matter of energy to me, a question of fuel. Sentimental people call it inspiration, but what they really mean is fuel. I have always needed fuel. I am a serious consumer. On some nights I still believe that a car with the gas needle on empty can run about fifty more miles if you have the right music very loud on the radio”

    Hunter S Thompson

  4. #4
    Audio Al is offline Pishanto Specialist & Super-Daftee
    Join Date: May 2012

    Location: Dagenham Essex

    Posts: 11,215
    I'm Allen.

    Default

    Does look badly burnt
    [

  5. #5
    Join Date: Nov 2016

    Location: UK London

    Posts: 236
    I'm Chris.

    Default

    Oh dear not good news, nice when you know how to fix these machines yourself, I can fix silly issues but when it comes
    to cct boards etc I would be a bit lost unless it was obvious.

    Reel to reel is great until they start playing up.

    Hope you get it sorted out.
    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

  6. #6
    Join Date: Jul 2010

    Location: Cheltenham

    Posts: 982
    I'm Charlie.

    Default

    Alan,

    Good luck with this. Fingers crossed for a happy ending.

    Best wishes,

    Charlie

  7. #7
    Join Date: Aug 2012

    Location: Hartlepool UK

    Posts: 1,640
    I'm Alan.

    Default

    Thanks guys hopefully the transistors will arrive Mon Tues and I can get it up and running again
    Meanwhile a trusty Tascam BR20 is standing in and doing a sterling job it doesent quite have the scale and drama of the A810 but its pretty damn good

    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

  8. #8
    Join Date: Aug 2012

    Location: Hartlepool UK

    Posts: 1,640
    I'm Alan.

    Default Back to life

    The Transistor arrived today so fitted it and reassembled the motor control board with fresh heat sink to both sides of the mica washer and tightly assembled this time checked that there is also good isolation between the BU 522 and the heat sink as it will short if there is continuity.
    Leaving the motor and control board out of the machine I ran through the check's in sec 3.5.9 of the service manual using an oscilloscope and multi meter and adjusted the pots to give the required readings, they were a little out of spec so good job I checked.
    Reinstalled the capstan and control board into the A810 and its working perfectly now and sounding superb happy days !

    I believe the cause of this problem could be that the transistors were not tightly fastened to the heat sink and Q1 has overheated or shorted on the heat sink?.
    I replaced this with the BD 522B which is a higher voltage rating than the original which may be beneficial as they do get hot in use I noted after the testing.


    20170516_175555 by Alan Towell, on Flickr

    Alan
    Last edited by 337alant; 16-05-2017 at 20:52.
    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

  9. #9
    Join Date: Jul 2010

    Location: Cheltenham

    Posts: 982
    I'm Charlie.

    Default

    Phew!

  10. #10
    Join Date: Aug 2012

    Location: Hartlepool UK

    Posts: 1,640
    I'm Alan.

    Default

    Quote Originally Posted by topoxforddoc View Post
    Phew!
    Absolutely !

    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

+ Reply to Thread
Page 1 of 2 12 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •