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  1. 73's de Edd

    Sony TAF40 LED Repair

    Sir dogtownman . . . . . . . . . (where do this dog town be ?) Initially place a jumper between both IC's pin 8 'S to see if the ? units dormant LED's come alive at higher levels. If not then pull and out and interchange the twin / companion IC's . . . to see if the conditions then move...
  2. 73's de Edd

    Technics SL-P101 CD-Drive Door Won't Open

    . Sir Dan . . . . . . . You can hear the load motor running . . . .but can you visually see its motor pulley engaged to the belt. I'll bet that the belt has "sagged" enough with time, that it is not griping within the pulley, and is slipping. 73's de Edd .
  3. 73's de Edd

    Drift issue in capacitance measurement, why?

    By the way, "I would certainly have suspected a stability when you used the controlled environmental chamber." so you think a chamber can't provide a stable environment? why? You must have misread . . . I said that of all of the test conditions . . . .I thought the environmental chamber WOULD...
  4. 73's de Edd

    What fuse would a need?

    Then . . . . . if you REALLY need to know the precise answer. Use your DVM in its DC Current function and place it in the 10 amp range and insert it in place of the fuse and read out the ACTUAL current consumption. 73's de Edd
  5. 73's de Edd

    vehicle external projection using laser beam on outside environment

    To wit: http://patents.com/us-20150298598.html 73's de Edd
  6. 73's de Edd

    Drift issue in capacitance measurement, why?

    . Sir Chengjun Li . . . . . . . I would certainly have suspected a stability when you used the controlled environmental chamber. Could you enact the same testing while utilizing "sets" of: 1 . . . . . N750 type ceramic capacitors 2 . . . . . NPO type ceramic capacitors 3 . ...
  7. 73's de Edd

    Technics SA-828 Receiver from 70s- Is it worth trying to save this aging patient?

    . Sir . . . . . . the Iceman cometh . . . . .from McMurdo . . . . . . .(Sound) Relevant to the two small / minor heatsinks: Notice that you have 2 Series arranged power transistors in the output stages, of each channel, so they are just taking heat sampling of a power transistor from...
  8. 73's de Edd

    Repairing old stereo

    Sir mkhb75 . . . . . . . The TDA7440D 28 pin I.C. which you are finding in that unit is for handling low level audio and tone control. You need to look around the boards until you find this part mounted on a metal heat sink for its cooling. Then, you will have found that circuitry...
  9. 73's de Edd

    Looking for components to make an IR controlled robot

    Sir Robert Hill . . . . . Taking your info that you supplied . . .your kiddo's toy only moves forward and backwards . . .with no turns to figure out in having an IR signal to track. For a further surprise, take that toy unit from the house and try to use it in the sunlit outdoors. Surely...
  10. 73's de Edd

    Technics SA-828 Receiver from 70s- Is it worth trying to save this aging patient?

    Well since you didn't take the FWB out of circuit for its testing. The erroneous reading from the AC to AC terminals of the FWB is actually being related to your BAD Q635 and Q637 transistors. There also might be collateral damage to immediately associated transistor / diodes. 73's de Edd
  11. 73's de Edd

    HTC Motherboard; need help to ID a component

    How lucky you were on that find ! Your initial information gave no information on that I.c.'s pin count with that associated ferrite inductor to its side suggests of that I.c. being a lm328 spin off series of DC-DC converter that operates from 3.6 dc and gives 3 sub power levels and has 3 LDO...
  12. 73's de Edd

    1972 IBM Selectric II typewriter with stuck carriage

    Sir Bruce Bills . . . . . . . Thru a time span of ~35 years I have had one initial model 91 and then two Selectrics and a final IBM Memorywriter. I am sustaining from any further keystrokes / info until I see if you ever show up here again. 73's de Edd
  13. 73's de Edd

    Technics SA-828 Receiver from 70s- Is it worth trying to save this aging patient?

    Sir Iceman from McMurdo . . . . . . . You say . . . " (care to explain the callsign - I'm curious)! " Hmmmmm . . . . . I had the two aspects of yours, solved from the get go . . .so I guess that I am up one on you. On the enigma . . . I will give you referencing to the first two, with the...
  14. 73's de Edd

    Help! plz making an amplifier board

    You forgot to install capacitor C9 on the board. You will get no audio, until you install that electrolytic capacitor . Just now read back and caught the bottom install. . .assuming that it's polarity is correct ? You have symmetrical use of two amps here. Take a meter and place it in it's DC...
  15. 73's de Edd

    Unknown component

    That's being exactly correct . . . . now give that man the free teddy bear which he just won ! You should also expect many other parts of that type around on the piece of equipments circuit board Plus, your equipment seems to have been assembled about 34 years ago. 73's de Edd .
  16. 73's de Edd

    Technics SA-828 Receiver from 70s- Is it worth trying to save this aging patient?

    Sir Iceman from McMurdo . . . . . . . Well, well, well in looking at your good photos of the boards, I see no abnormality as far as any burnt resistors or cracked green and black power output transistors . You may just find yourself having the rare abnormality of finding an open diode...
  17. 73's de Edd

    Technics SA-828 Receiver from 70s- Is it worth trying to save this aging patient?

    . Sir Iceman from McMurdo . . . . . . . . (Don't your turbines get iced up a lot ?) If the Gods are with you and all planets are lining up precisely . . .testing all of the diodes within YELLOW boxed markup probably will result in one or a couple of ZERO ohm dead shorted units being your...
  18. 73's de Edd

    Repairing old stereo

    Sir mkhb75 . . . . . . . Can you confirm for me, if the potted audio output module on your unit is being a TDA7265? This info is probably all that you need if you are using line level audio into it. Relevant Schema Snippet: 73's de Edd
  19. 73's de Edd

    How to build a 455khz oscillator for a signal generator..

    Sir Kennynva. . . . . . . . . . . . . Messrs . . . Hop, Davenn et Dorke . . . . . BEHOLD . . .ye olde tyme . . . . . . Amphenol 75 series microphone connectors: You say . . . . . " I would like to tune the IF transformers of old tube radios.." Do I detect a plurality there ? . . ...
  20. 73's de Edd

    Amp In Protection Mode

    Sir Rick 79 . . . . . Looking at YELLOW boxed area of the board photo below. does it look like R676 . . . .a 390 ohm 2 Watt film unit might be the principal cause of the heat generation in the "Hotter'n Hell " PCB's scorched area, and is being sooooo bad that it has carbonized the pcb? OR...
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