Ashton GA80 guitar amp (Australia)

Discussion in 'Electronic Repair' started by N_Cook, Nov 11, 2009.

  1. N_Cook

    N_Cook Guest

    RoHS date of introduction for Australia ?
    Anyway 1/4 inch i/p socket too weak even for domestic use , breaking up in a
    few years ( within RoHS regime), no obvious datecodes except main electros
    seem to be 2000, otherwise maybe 2004 or 2005 IC dates. No-name flimsey junk
    , the type with 2 insulated change over contacts. On trying to work out the
    functions, apart from the tip contact/grounding setup there is a line to one
    of the isolated switches that grounds at plug inserted and o/c when removed
    , it goes DC connected to the base of a pnp transitor - function ?
     
    N_Cook, Nov 11, 2009
    #1
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  2. N_Cook

    N_Cook Guest

    N_Cook <> wrote in message
    news:hder6j$jg8$-september.org...
    > RoHS date of introduction for Australia ?
    > Anyway 1/4 inch i/p socket too weak even for domestic use , breaking up in

    a
    > few years ( within RoHS regime), no obvious datecodes except main electros
    > seem to be 2000, otherwise maybe 2004 or 2005 IC dates. No-name flimsey

    junk
    > , the type with 2 insulated change over contacts. On trying to work out

    the
    > functions, apart from the tip contact/grounding setup there is a line to

    one
    > of the isolated switches that grounds at plug inserted and o/c when

    removed
    > , it goes DC connected to the base of a pnp transitor - function ?
    >
    >


    If it kills the gain for bang-less plug insertion then it would only work
    for insertion , not removal, as that switch makes before tip makes/breaks
    ground
     
    N_Cook, Nov 12, 2009
    #2
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  3. N_Cook

    N_Cook Guest

    Gareth Magennis <> wrote in message
    news:8gQKm.112991$F%2...
    >
    > "N_Cook" <> wrote in message
    > news:hdghi1$lb7$-september.org...
    > > N_Cook <> wrote in message
    > > news:hder6j$jg8$-september.org...
    > >> RoHS date of introduction for Australia ?
    > >> Anyway 1/4 inch i/p socket too weak even for domestic use , breaking up
    > >> in

    > > a
    > >> few years ( within RoHS regime), no obvious datecodes except main
    > >> electros
    > >> seem to be 2000, otherwise maybe 2004 or 2005 IC dates. No-name flimsey

    > > junk
    > >> , the type with 2 insulated change over contacts. On trying to work out

    > > the
    > >> functions, apart from the tip contact/grounding setup there is a line

    to
    > > one
    > >> of the isolated switches that grounds at plug inserted and o/c when

    > > removed
    > >> , it goes DC connected to the base of a pnp transitor - function ?
    > >>
    > >>

    > >
    > > If it kills the gain for bang-less plug insertion then it would only

    work
    > > for insertion , not removal, as that switch makes before tip

    makes/breaks
    > > ground
    > >
    > >

    >
    >
    > Maybe it mutes the reverb?
    >
    >
    >
    > Gareth.
    >


    Luckily the owner wanted a reliable input socket and was unconcerned about
    the loss of the plug-in de-thump cct. To replace the domestic headphone
    socket (has isolated switching) would have been a work up as 0 or 15V on
    that control line so could not use an effects pedal type ring switch action.
    And the ring switch for a normal stereo 1/4 inch jack is the wrong action
    for here anyway, requiring an inverter somewhere or one of those awkward and
    rare offset 1/4 inch switch actions. cct proper, holds off full gain for 0.5
    seconds or so after plug insertion, all the while removed 30dB or more gain
    drop via 15/-15V control into the first amp. Although no obvious PbF solder
    problems the original input socket had thin+wide blade pins going into holes
    of that wide diameter and loads of filler solder, asking for problems with
    ordinary solder let alone new-fangled


    --
    Diverse Devices, Southampton, England
    electronic hints and repair briefs , schematics/manuals list on
    http://home.graffiti.net/diverse:graffiti.net/
     
    N_Cook, Nov 12, 2009
    #3
  4. N_Cook

    N_Cook Guest

    More as a reminder to myself, for the next time this problem appears. A work
    around without having to cut into the existing cct to put in an inverter.
    Use a small SPDT relay (+emf diode) with power adapted from whatever
    convenient rail.
    Permanent ground on the flexing ring contact in a 1/4 inch TRS socket and
    the fixed ring- contact to the low side of the relay.


    --
    Diverse Devices, Southampton, England
    electronic hints and repair briefs , schematics/manuals list on
    http://home.graffiti.net/diverse:graffiti.net/
     
    N_Cook, Nov 13, 2009
    #4
  5. N_Cook

    N_Cook Guest

    N_Cook <> wrote in message
    news:hdj5bg$du7$-september.org...
    > More as a reminder to myself, for the next time this problem appears. A

    work
    > around without having to cut into the existing cct to put in an inverter.
    > Use a small SPDT relay (+emf diode) with power adapted from whatever
    > convenient rail.
    > Permanent ground on the flexing ring contact in a 1/4 inch TRS socket and
    > the fixed ring- contact to the low side of the relay.
    >
    >
    > --
    > Diverse Devices, Southampton, England
    > electronic hints and repair briefs , schematics/manuals list on
    > http://home.graffiti.net/diverse:graffiti.net/
    >
    >
    >


    The added delay, due to relay action, only adding to the desired effect of
    delaying the removal of the gain suppression until after tip contact is made
    ( unless someone is very slow at plug-in)

    --
    Diverse Devices, Southampton, England
    electronic hints and repair briefs , schematics/manuals list on
    http://home.graffiti.net/diverse:graffiti.net/
     
    N_Cook, Nov 13, 2009
    #5
  6. N_Cook

    N_Cook Guest

    Robert Macy <> wrote in message
    news:...
    On Nov 11, 9:10 am, "N_Cook" <> wrote:
    > RoHS date of introduction for Australia ?

    ....snip...
    the answer I got was,
    "Not on the radar."


    RoHS printed on pcb overlay, and definitely grotty PbF-looking solder (but
    not any actual observable or twizzleable bad joints). No RoHS stickers on
    the outside, so presumably standard asian product internally, badged as Oz
    externally
     
    N_Cook, Nov 17, 2009
    #6
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