9241 tc - Si652 fuse burning

      9241 tc - Si652 fuse burning

      Dear all,
      My 9241 worked normally for a few days. In one day - I connect deck. Worked normally a few hours, normally switch to FM, and for deck without any problems.
      Some day during deck working, I increase volume (to 3...4 led) - saba shut down. Normally can on/off in main switch (stand-by led is working), but fuse 1,25A Si652 is burning always when want switch on receiver.
      Relay RS653 is working (I hear). Transformer 651 - I hear-is working.
      PS: maybe this problem is described in this forum, but deutsche language is dificult for me...sorry, but ich Gerade jetzt intensiv.
      Dear surec,

      Your unit type no. is 9141 tc.

      You need to remove the +32V and -32V connections from both power amp modules (make sure the open contacts don't touch anything - or isolate them). If the Si652 fuse now stands, you have one of the power transistors on the right or left power amp stages blown (CE shorted).

      Reconnect the power amp stages one after the other, to check if the blown transistor is on the right or left amp module.

      If there is no power transistor blown, the rectifier D2211 or one of the large caps (C2213 or C2214, 10000 µF) must be defective (shorting the voltage to ground, thus too high current).

      Good luck!

      Best regards
      Dear Reinhard,
      Thanks. After disconnect St26 - fse burn again.
      I check D2247 (no 2211) - exist D2248 - working good.
      I have no tool to check 10 000uf, but observed, during checking resistance by multimeter:
      - one cap is in first is charging (from multimeter), and resistance is rising. After that voltage in cap is some mV
      - second cap have zero resistance, and no any mV in output after miltimeter resistance test
      I think second is defective, but I need to change both to be sure a capacity and to be sure working in future.
      Could You tell me, needed Elco, or I can put some similars caps?
      My Elco is assembling by screw, but I think it's old solution, new is by some glue.

      Fitting St28 for Power mod. (no15) and other connections from TR601 - maybe this it's problem too?
      Dear surec,

      Sorry I meant D2216 (Se- rectifier on the main board). Also check the capacitor C2216 (100 µ) next to it. There is a 2,2 Ohm in series with D2216. Actually the resistor should blow with overload. Nevertheless, better to check.

      You said D2247 is OK?


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      Dear surec,

      OK, you found the culprit.

      Of Course you may use the elkos you linked.
      However, it will require that you locate + and - on the board for each and drill small holes at through the board at the right spots so that you can connect the pins from the new Elkos with the right polarity and solder them tightly. The new ones will not fit into the existing holes. Needs a bit creativity and planning, but doable.

      Dear Surec,

      if I understand this right, the defective capacitor is one of the main ones, right next to the transformer, right ? If so, 10 000 uF / 40 V is fine, but 50 V or 63 V is fine, too. However, I'd try to use one of the same form and size, also with the bolt and nut mount at the bottom. There are newer makes than the Roederstein you have in the link. Fisher und Tausche (F&T) still produces them, they are good quality. Normally, you can find them on ebay, too. I'd not go for NOS parts here, as you never know how they were kept and stored all those years ...

      10000 uF 40 V F&T sell for 4 ... 6 Euro a piece, with heatshrink isolation, so that should be no problem. They will be a bit smaller than the old ones, so also the 63 V version will fit in. Soldering pins should be similar to the old ones, so it should all be a simple exchange.

      Good luck,

      Dear surec,

      sorry, I see from your and Michael's answer that I wrongly assumed that in the 9141 the Elkos are similar as in 92xx series. Obviously you need those with bolt and mount as Michael said and you linked to the yellow ROE elko. The linked ROE are new old stock, less preferable than new Elkos of the same style.

      Best Regards,