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  1. 73's de Edd

    unbiased portion of transistor

    I was just about to quiz you about the SCR that the unit used so I would know its gate sensitivity. Now you mention [an original] being involved, and I perceive of your having a new one in your hand now. The new China one extremely suggests of being BAAAAAD. If it so happens that you still...
  2. 73's de Edd

    Distorted audio on an old transistor radio cassette

    YOU GOT IT ! and yes: You Do I need to use almost the same value (uF) of the original capacitor. Except for that / those 2000 ufd units, you can try a 470. 73s de Edd
  3. 73's de Edd

    Circuit Board for Human Touch EMS-12 Massage chair

    My . . .my . . .MY . . . how simple can that be, just two 90 degree offset, magnetic reed switches. And only their 4 connections. Somewhere? way . . .way . . .WAAAAY . . . .deep down within the internals, think that you can find the urea phenolic square shard (s) . Or will it have to be...
  4. 73's de Edd

    Distorted audio on an old transistor radio cassette

    Splay the + and - wires of the capacitor apart, so that you can then press your red wire of the test capacitor against the red + solder blob of the units capacitor. Then you swing the - lead such that the same mating can be done with the black- solder blob of the units capacitor.
  5. 73's de Edd

    unbiased portion of transistor

    Sir chet . . . . Is there a strong possibility that you have one of these and it is inoperative ? Looks like one other person had this situation and he also plotted up a schematic. I copied his and reversed the right to left positioning of what he drew up as a 3 terminal regulator. It now...
  6. 73's de Edd

    Need Help Repairing Bicycle LED Lights

    . Sir JohnS0N . . . . . HOW IT WORKS: Here is the operation of your unit, all explained within the illustration: There is the Lithium cell at the left and the dotted yellow line indicates the reforming bend needed to be restored to get battery clamping contact again. Looking at the right...
  7. 73's de Edd

    unbiased portion of transistor

    Sir chet . . . . . Is there a possibility that you have just encountered your first encounter with a darlington connected pair of transistors.Its used to get some phenomenal gain possibilities. The first depiction is the Darlington and the second is a variance to the circuit to tailor the gain...
  8. 73's de Edd

    Circuit Board for Human Touch EMS-12 Massage chair

    . Sir Kenneth Gray . . . . . Give us a photo closeup . . .with it being well lit and focused-no reflections-just a full frame fit-non tilted. Of BOTH sides of the board and we will see what we can analyze, what we can see from it, and what can be done with repair of that existing board...
  9. 73's de Edd

    Distorted audio on an old transistor radio cassette

    Yes those values should work just fine with you then only needing to find two 47 or 50 µF for two of the capacitors and then that large 2000 . Consider even using as low as 470-500 for it, just in evaluation. DO YOU REALIZE that since this set is using a large PCB and not a microsize one like...
  10. 73's de Edd

    Help identify electronic components

    Sir sti . . . . . . . You have 3 other [ LX ] input inductors to be able to get their markings from. Any of which, you did not give us a close up of . The other appears to be a Sanyo (or a knock off ) Poscap Dry tantalum B2 series E8 suggesting 150 ufd and the j as 6.3VDC voltage...
  11. 73's de Edd

    What component is this?

    A continuance . . . . . . Moreover it is being a faster switching, high current inductor, of ~4.7 uh inductive value. If pulling the heat shrink covering for inspection, you would find the windings nestled down within a " dumbell " ferrite core. For enhancement of its magnetic...
  12. 73's de Edd

    Distorted audio on an old transistor radio cassette

    Sir Richard 9025 . . . . . . . . Last "easy fix" probability, listed in most likely cause to effect. Significant decline of capacitance due to age and time related electrolyte dry out: C35 C14 C15 C22 C23 C36 In the audio amplifier section. 73's de Edd Add on, after just hearing the audio...
  13. 73's de Edd

    Distorted audio on an old transistor radio cassette

    Sooooooo is that the unit in question. I hear no distorted sound . . .per se. All of your audio on the AM band is about what I would expect as normal sound with that units speaker. Sounds good to me . . . .particularly at sound bites : 17:37 and 18:01 and 18:14 Typical weird . . . ...
  14. 73's de Edd

    Distorted audio on an old transistor radio cassette

    . Sir Richard9025 . . . . . . . Ahhhhhhhhhh yes, with those given voltage readings . . . .looks like you have thrown in a new variable to the situation. They are being based on a 12.5 VDC supply voltage. YET . . . . . . . if you analyze them proportionately and ratiometrically, they still look...
  15. 73's de Edd

    Crate BT-100 Bass Amp Blowing Fuses

    Sir Matthew667 . . . . . Considering that you do have a 100 watt incandescent lamp connected in place of F1 and it does light up brightly. Consider that indicative of this linear supply STILL trying to function, but just being power starved by that lamp. Try taking dc meter measurements at...
  16. 73's de Edd

    Denon AVR 1804 amp won't switch on

    Nope . . . .it's presently in saturated conduction. Will detail that circuitry's aspects tomorrow. 73''s de Edd
  17. 73's de Edd

    Tektronix 2430 repair

    That used to be common practice back in discrete component days . Even the use of a dishwasher . Myself, I would use hot water, a hog bristle brush and either Fantastic or 409 ,more scrubbing, a rinse and use a final " sling drying ". Then a spaced away heat gun for the final traces of...
  18. 73's de Edd

    Denon AVR 1804 amp won't switch on

    Yep. . . . That was exactly what was expected. Now place that transistor base connection into place the final time . . . .lead fatigue willing. Then another DC voltage reading from its collector to ground /emitter , to confirm what that voltage level is with that stage in full conduction...
  19. 73's de Edd

    Need help identifying LCD screen...

    Equipment brand and model . . . .From whence it did emanate . . . .forthwith ?
  20. 73's de Edd

    Tektronix 2430 repair

    . Sir bigone5500 . . . . . .aka Jared . . . . . Firstly I wonder if you have tried adjusting the green blob control to its optimum ?. Also, next, see if the bottom left intensity control causes it to get worse at its maximum CW position, or getting better at its adjustment range towards the...
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