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Yash Jaiman <yashjaiman447@gmail.com>: Jul 08 08:31AM -0700 On Saturday, January 21, 2023 at 2:20:18 PM UTC+1, Tomas Paquot wrote:   > > contact me to : matt...@gmail.com mattosbw1(at)gmail.com   > > ___________________________________________________________________________________________________ > > please send Solution Manual Electronics : A Systems Approach (5th Ed., Neil Storey)   Can you please send Solution Manual of Electronics: A Systems Approach (5th Ed., Neil Storey)

Jeroni Paul <JERONI.PAUL@terra.es>: Jul 07 12:24PM -0700 Dave Platt wrote: > "over-discharge", and depending on the specifics of the battery > chemistry it can cause the over-discharged battery to "charge up in > reverse" a bit, and develop a reverse-polarity output voltage.   This is exactly the reason. When I was a child toys were fully analog and had no low battery cut-off, so I used to run my remote controlled car until it stopped completely. I had a battery tester and commonly saw the needle go the opposite direction with some cells. It used four AA cells in series. Once I was curious and installed one of these cells reversed in a clock and it ran some days.   To avoid reversing rechargeables moden gadgets have a low-battery cut-off, for example if using four 1,2V cells it should cut at 3,8V so that the worst case three full cells and one empty will not reverse the empty one.

David Farber <farberbear.unspam@aol.com>: Jul 07 10:16AM -0700 I had two Sound Technology 1700B analyzers. One worked fine. The other, which I gave away to a fellow tech friend, had a problem only when you were trying to make a distortion measurement that was less than 1% (e.g. 0.3%, o.1% etc.). When you enter those smaller ranges, the analog meter pegs. I searched for a service manual online and fortunately was able to find it though now I have to troubleshoot from long distance. You can download it from here: https://app.box.com/s/1l0s5z4zlah43krmfmeonhn1srva1fha (pages 43-44 contain the schematic of the distortion analyzer section)   When trying to analyze what circuitry changes occur when shifting from the 1% distortion scale to any level below, I am stumped by the schematic diagram of the Ratio/dB switch. In one area on page 44, labeled "ATTENUATOR," it is self-explanatory that the wiper on one of the wafers steps through a voltage divider network that changes the level by +/- 10dB for each turn of the switch. I was thinking that maybe one of the resistors in the voltage divider opened up to upset the balance of the divider network however any resistor (R219-R233) that opens up in that network would effect the higher range as well as the lower range. So far, everything in the schematic makes sense to me.   Next if you scroll down and to the left you will come across the, "PHASE NULL CONTROL" and the AMPLITUDE NULL CONTROL." Again the RATIO switch is tied into these circuits. Here is where I cannot understand how the circuit changes as the switch is moving the contacts from one position to the next. Let's start with the PHASE NULL CONTROL circuit. On the left side of the diagram, you see S2AF and underneath it is a vertical, solid black line. In the middle of the black line there is a terminal labeled, "6." which appears to be connected to the .1 contact of the Ratio switch. If that vertical, solid black line means that those top 5 nodes are all in common, then the positive ends of C314 and C315 should be tied together. Using my working machine, a quick check with my multimeter verifies those capacitors ore now wired in parallel however if I move the switch two clicks to the 1% range, then according to the schematic, those capacitors should not be in wired in parallel. My multimeter says they are still wired in parallel. Now either the schematic drawing is incorrect or I am misinterpreting how the RATIO switch is shifting its connections as it steps through the different ranges. The same situation arises in the very similar AMPLITUDE RANGE CONTROL CIRCUIT. Capacitors C325 and C326 are wired in parallel no matter where the function switch is turned.   In summary, I think something is throwing off the DC input voltage to one of the op amps and I was suspecting a leaky or shorted cap however since I now have doubts about the circuit wiring in the schematic as compared to what I see inside the analyzer, I am not so sure.   Thanks for your replies.   -- David Farber Los Osos, CA

Three Jeeps <jjhudak4@gmail.com>: Jul 07 10:11AM -0700 On Thursday, July 6, 2023 at 7:05:47 PM UTC-4, John Robertson wrote: > (604)872-5757 (Pinballs, Jukes, Video Games) > www.flippers.com > "Old pinballers never die, they just flip out."   This makes me wonder if this end state of calibration data vanishing after xx years was a design requirement (specified by who?) or a byproduct of the design approach taken (to increase machine flexibility? reduce parts count? etc.).

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