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Vintage HiFi maintenance season

Jan Cumps

I have an early 70s receiver that needs some maintenance. The switches and pots have become scratchy again.

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It's the second time that I'll be servicing it. The first time I did a full check, and fixed the lights. This time it's just a clean-and-lube of the dials and push buttons.

Parents

  • Hello 

    i would start by spraying switches and pots with DEOXIT D5,

    Has this been used on a regular baises, if NOT power it up (with a 100w lamp in series with the ac power input) for few hours.at low volume 

    if it has noisey transisters in the output stage or tone controls the lamp will stop descruction of output stage

    most of the time i found noisey transisters were the small PNP ones

    if one channel has more gain than the other when in mono  then start looking for caps in tone and power amp circuit

    i think this is only the baby model the big ones had 4 channel for BI wire or external Quad box 

    if someone wants to start compairing class A or B amps to class D please start another thread

Reply

  • Hello 

    i would start by spraying switches and pots with DEOXIT D5,

    Has this been used on a regular baises, if NOT power it up (with a 100w lamp in series with the ac power input) for few hours.at low volume 

    if it has noisey transisters in the output stage or tone controls the lamp will stop descruction of output stage

    most of the time i found noisey transisters were the small PNP ones

    if one channel has more gain than the other when in mono  then start looking for caps in tone and power amp circuit

    i think this is only the baby model the big ones had 4 channel for BI wire or external Quad box 

    if someone wants to start compairing class A or B amps to class D please start another thread

Children
  • in reply to acdc90

    > i would start by spraying switches and pots with DEOXIT D5

    That's the plan

    > Has this been used on a regular baises, if NOT power it up (with a 100w lamp in series with the ac power input) for few hours.at low volume 

    > if it has noisey transisters in the output stage or tone controls the lamp will stop descruction of output stage

    It's in daily use

    > most of the time i found noisey transisters were the small PNP ones

    > if one channel has more gain than the other when in mono  then start looking for caps in tone and power amp circuit

    It has no issues except for noisy switches and pots. i serviced it about 10 years ago.

    > i think this is only the baby model the big ones had 4 channel for BI wire or external Quad box 

    Yes, it was the low power, low budget model of their range at the time.