BeoGram 4000 tone arm problem…

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  • #11620
    Gravity Graham
    SILVER Member
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    Thanks Craig – I’ll check out the diodes.
    I’ve already ordered a batch of new transistors, but I like your thinking about switching the inboard and outboard transistors..!
    Also, after your recommendation, I have just ordered an Atlas DCA pro – as an early Christmas present from my wife (she’s the one who wanted it made operational again!)
    I’ll update this post as I progress…

    Best Regards – Graham H.

    #11630
    hcraig244
    SILVER Member
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    Found this in a 2012 – 2022 archived post “justins BG4000”

    Powered up and this is what transpired:

    unit sat powered up with no actions
    upon hitting Start the platter drive started up at 33rpm
    the panel ilumination lamps came on
    the 33rpm speed selector lamp cam on
    However the transport drive motor didn’t run, I could change the speed from 33rpm to 45rpm but no other functions responded. Time to look at the circuit diagrams…… 

    This is what I found….the following components where shot:

     

    1D11 Diode
    1TR33
    1TR31
    1TR30
    1TR32
     

    All of the components on the opposite side of the motor tested good.

    Untitled5

     

    #11710
    Gravity Graham
    SILVER Member
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    OK Craig – I thought I’d responded 2 days ago… Gone missing…
    (Edit – didn’t realise it had moved onto another page..)
    Update:
    I have ordered an Atlas DCA Pro as advised (early Xmas pressie from Missus) <3
    I’ve got a few other bits to sort out while I wait for new transistors to arrive.
    Now I’ve had a couple of lamps blow… probably from the switching on and off…!!
    (So not switching transistors until they are replaced..)
    While I’m at it I’m cleaning all the contacts  with cleaner and a glass-fibre brush/burnisher.
    Just wishing I had more workspace, so I could do some fault-finding on my Beomaster 1900…..!!
    Regards
    Graham H.

    #11888
    Gravity Graham
    SILVER Member
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    Think I have it sorted now..
    Changed out TR28 and TR31 – nothing changed.  Took out TR29 and TR30, and tested them with my new Atlas DCA semiconductor tester – to find that TR29 has a short. !!
    Followed up by switching them, and lo-and-behold, the deck will return and switch off (after winding the slider towards the middle !) – and as expected, the tone-arm will not travel inwards..
    Replacement transistors will hopefully arrive today, and I’ll replace all 4 as a matter of course..
    I don’t suppose you know where I can get replacement 6v 30mA lamps for the 33/45 indicators ? I also need 2 replacement 12v 30mA lamps for the position indicator ?
    Regards
    Graham H.

    #11938
    hcraig244
    SILVER Member
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    Dillen (Martin) from this site is your man……he can supply the correct lamps for you, send him a line.

     

    #12113
    Gravity Graham
    SILVER Member
    • Topics Started 3
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    Thanks Craig – actually got the lamps from BeoParts (Denmark).
    However, After changing out the transisistors – it all worked (At last !!) – THEN..
    I reassembled the deck and nothing worked !!
    Not sure how – but TR29 & TR30 have packed in…
    So – before I replace them again – I’ll check all the diodes.
    Graham H.

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