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Crate SMPS in V-series models (V33H & V60?)

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  • #1

    Crate SMPS in V-series models (V33H & V60?)

    Hello Folks,
    I found D103 (D104 in the schemo) to be shorted. SMPS just pulsed and wouldn't start thanx to protection. The only diode that I and the tech at Mouser could find that was close to the original CR2010 was the FR207G-B.
    Well, the amp came back with the same D103 shorted. I'm not sure if it is because of the longer Reverse switching time of 500ns vs the 100ns of the CR2010. I will order more of the FR207G-B and make certain the power tubes, albeit new, are either shorting or if there's some other issue with the amp.
    All the caps in the SMPS check good on the Sencore LC103 and none are bulged.
    I'll chime back in when I have a conclusion.
    glen
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  • #2
    Since the diode shorted, I'd replace the filter cap just in case it got hit with reverse Voltage.
    WARNING! Musical Instrument amplifiers contain lethal voltages and can retain them even when unplugged. Refer service to qualified personnel.
    REMEMBER: Everybody knows that smokin' ain't allowed in school !

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    • #3
      It could also be an arcing output tube that arcs fast enough that the fuse doesn't blow. Speaking of fuses, I'd also make sure that FUSE3 is the correct value and someone didn't put the wrong value there. Your diode cross should be just fine.
      "I took a photo of my ohm meter... It didn't help." Enzo 8/20/22

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      • #4
        Where's D104?

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        • #5
          Originally posted by Mick Bailey View Post
          Where's D104?
          In the SMPS. I believe D104 marked on the board is actually D105 on the schemo. There appears to be no D104 in the schematic. The diode marked D105 on the board layout doesn't exist in the schematic.

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          • #6
            Thanx all for the suggestions. I am ordering more FR207's since there appears to be no other exact replacements for the originals. I'll probably replace the output tubes & pray!

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            • #7
              Whilst L103 and C119 look to be there to filter HF out of the supply, I would check them anyhow around the component legs for solder cracks.
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              • #8
                Hi, were you able to repair the SMPS?

                I have the same issue and I’m wondering if I should attempt to repair it or replace it with a transformer?

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                • #9
                  Originally posted by megatrav View Post
                  Hi, were you able to repair the SMPS?

                  I have the same issue and I’m wondering if I should attempt to repair it or replace it with a transformer?
                  No transformer issue with this Crate. Perhaps you were responding to another post in this string.
                  In my case, yes, The diode FR207G-B from Mouser did repair the SMPS. I checked the caps in the primary (w/Sencor LC103) & they all checked good.

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