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  1. 73's de Edd

    My yamaha rx-a660 stereo system is frozen

    . Sir warslayer123 . . . . . . . . mmmmmmmm . . . . possibly . . . . .but it will require a bit of prep work and initial sleuthing feedback from you. Initially remove top clamshell cover to expose the units innards . . . .take AC power cord in hand and trace that line to a connection into a...
  2. 73's de Edd

    TDA1554 Melting

    MUCH mo' better . . . . . . but don't the main filter capacitor foils need to be extended out a bit more, in order to make physical clearance from the heatsink fins on the component side ? By all means, leave the companion HF bypassing ceramic cap up nearby the chip, as you have it , just...
  3. 73's de Edd

    TDA1554 Melting

    .Sir adamdavies986 . . . . . . . . the 1st If you were able to fry one of those units, then I guess that unit doesnt have as good of a thermal shutdown and cutoff /protective features as its old grandfather 1875 series did. I usually just like to refer to application notes from the IC...
  4. 73's de Edd

    TDA1554 Melting

    Your now loose pin, may well be related to the meltdown and fracturing of the chip during overload. MOST importantly, no provision of DC isolation of the audio input of that Chip is being provided by the presence of a set of 0.22 UFD capacitors at its audio input pins . . . . check the provided...
  5. 73's de Edd

    Problems with sound circuit on a toy train

    Sir Flash215 . . . . . . . . . . . Боже мой . . . . . . . . we like whats on after your video . . . . We have the remote receiver board at one end of the board and then in its center, to its side, we have voltage regulation, then the brains and interfacing at the center and then finally the...
  6. 73's de Edd

    TDA1554 Melting

    Sir adamdavies986 . . . . . . . . Initial Observations / Considerations 1 You have your Power supply electrolytic at one side of the board and its companion HF/RF ceramic decoupling capacitor at the complete opposite side of the board with all of that inductive foil path between them. 2...
  7. 73's de Edd

    Thermal Fuse Ghd please help..

    The reason for giving you so many options is that I thought that at least one of the options would exactly fit your units situation . There is a possibility that you cut the wires of the old unit about right in the middle and you have found a new unit which is actually just the naked "Little...
  8. 73's de Edd

    Wiring DPST illuminated switch

    . Sir dataworx . . . . . . . . . . . . As you have said . . . . I have wired the switch in already and it is working as expected. The only question then, is if the units LED is illuminating adequately, if so, then they have improved upon the ultra simple wiring such as their illustration has...
  9. 73's de Edd

    Thermal Fuse Ghd please help..

    Mme Amy . . . . . . If being my situation . . . and MY problem to solve . . . . . FACTOID . . . . . . . . The biggest error a person could make in replacing these thermal units is the damaging of the units by the soldering of their connections and damaging the element by excessive...
  10. 73's de Edd

    Wiring DPST illuminated switch

    . Sir dataworx . . . . . . . . . . . . Tsk . . .tsk . .tsk . . .One dinky little drawing from their catalog page , not even identifying the 4 terminal connections, but they sure wanted you to know the hole sizes . If you are wanting use of the switch for AC power switching of both legs...
  11. 73's de Edd

    Radio

    Sir Martin mildon . . . . . . . . . . . . Nope . . . looks like that units u/p interfacing complexity would be modifying a continually refreshing digital stream from the u/p into the AM-FM radio block, with particular emphasis on the 15th data bit. I then thought of the FM units that I got...
  12. 73's de Edd

    Need help identify part

    .Sir tbm700 . . . . . . . . . . . . But . . .but . . . . . SCR 210 numbering does not validate, but that very distinct MOTOROLA logo with a code date of the past of the 12th week of 1994 will equate. With it agreeing with their MAC210-6 units and with it being a SCR . . .but a dual...
  13. 73's de Edd

    Thurlby PL310 power supply fault

    Sir Paul Ramsbottom . . . . . . . . . . . . Initially, in a no power on and having BLED down filters situation. Use ohmmeter to confirm no dead shorted . . . nor leaky( C-E junctions of ) . . .Q2, Q3 and Q1 transistors. If all OK you could initially monitor Q3 emitter with that present...
  14. 73's de Edd

    Radio

    Sir Martin Mildon . . . . . Looks like the guess on the mute is correct . . . . just that you wanted to disable the mute. The accompanying mark up is identifying the relevant circuit functions. THE . . . one of interest, will be the GREEN STAR referenced one. Its usually just a one...
  15. 73's de Edd

    Radio

    Sir Martin mildon . . . . . I have not yet been told of the need of muting the units speaker ?, but if that is the case / need plugging in the headphones should accomplish the muting of the units speaker. If no headphones, an 1/8 inch by 1 inch long round wooden dowel rod should also...
  16. 73's de Edd

    Broken TV Switching power supply

    Sr Edugimeno . . . . . Heyyyyyyyyyy . . . . .hombreeeeeeee . . . . ¿ Qué pasóóóóóóóóóó ? Ahhhhh yes . . . . just shed the loads and then pinpoint the problem loading down the unit. Certainly was not expecting that low drop out threshold 12VDC / 2 amp 278 R12 regulator to be at fault. BUT on...
  17. 73's de Edd

    Broken TV Switching power supply

    Sir Edugimeno . . . . . Initially check by ohmming across C224/6 12 V supply storage capacitors to see if an overloading on that supply output is causing the power supply to cycle off and on. Then move across C214/5 to ohm out in the same manner to confirm that 5V line is not being overloaded...
  18. 73's de Edd

    Help, I need to identify burnt chip.

    Sir Revol . . . . . . . . . . On small 12 in units like yours and on down to tablet sizes and digital display picture frames.. The PT4115 has been extensively used as a buck converter and LED backlight controller Take this data sheet and initially note on page 2, that your unit is being in the...
  19. 73's de Edd

    repairing problem with pc SMPS power supply

    Sir tharindunn . . . . . . . Ahhhhhhh so . . . . you have WANNIEN power supply. Your zener identifier IS being a valid number string, but with none of their units falling in the lower 2V ( 2V1) range or being as high as a 20 V value ( Their max voltage offering is being 18V.) No idea on the...
  20. 73's de Edd

    How To Make Sure This Led Is Working

    Sir Pharoan . . . . . . . If mine olde eyes are correctly seeing the color bands of the resistor as being Blue Gray Gold Gold, then that 6.8 ohm dropping resistor and your parallel arranged 3 LEDS . . . . . along with their phospor doped overlays, suggesting of these probably being WHITE...
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