Daiwa PS-304 Problem

Discussion in 'Radio Circuits, Repair & Performance' started by NYKOC, Oct 20, 2016.

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  1. NYKOC

    NYKOC QRZ Member

    Good afternoon, my name is Nicolas, I send greetings from Argentina.
    I want to ask for help with a problem I'm having.

    I have a old power supply Daiwa PS-304 when lit noticed that the volt/amp meter is not working.
    Well, is not very serious problem but when I measured the output is only 12.8V

    I check the key voltages in a diagram found in a post in this forum.
    But now I do not know how to go and find out the problem. (Sorry, my English is horrible)

    Voltajes Outputs
    Transformer Main=18 VAC
    Transformer Sec= 5.5 VAC
    PS Max Output= 12.8v
    Rectifier bridge= 24v

    The next values was measured with volume in the middle. I think must be 13.8v (I have 11v)

    8230 board Pins:
    13&14= 5.5 vac

    IC1 Pins:
    1=.638 8=9.72
    2=28.6 9=3.06
    3=15.2 10=3.06
    4=30.6 11=0
    5=12.8 12=6.37
    6=12.4 13=6.37
    7=29.5 14=14.59

    C1815 Transistor:

    Any ideas?
  2. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    Did you adjust potentiometer RV1 (near IC1 on the board), which sets the output voltage?
    NYKOC likes this.
  3. NYKOC

    NYKOC QRZ Member

    Dear WB2WIK, thanks for your response!
    I get 13.8v only for a moment, then the voltaje drop again.
    I will try to clean RV1
  4. NYKOC

    NYKOC QRZ Member

    Dear WB2WIK, I want to say thanks. I changed the 4 presets and now the output and the voltimeter work again!
    thanks for your advice!

    KA9JLM likes this.

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