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wally

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    Sunnyvale, California, USA
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  1. All of the 4 Pismo batteries I have examined use the Benchmarq, now TI, bq2040 Gas Gauge IC. In addition there is a Seiko S-8233A Battery Protection IC and a series switch, an NEC uPA1712 MOSFET. And I think possibly a chemical fuse that gets blown if the voltages or currents sensed get too extreme. Often the older batteries die during discharge by the S-8233A undervolt detecting the weakest cell section before the whole pack voltage drops enough to trigger a valid gauge AH capacity downwards recalibration. To the user this looks like the onscreen battery time indicates some normal amou
  2. You read that correctly. Notice how there is a message with some of the different caps with what current they picked to run the endurance testing. The 321 mA cap has really big hours rated, but be assured that if run at an amp or more of switching supply ripple (commonly encountered in power supplies), it would heat up inside and most of the other caps listed would likely outlast it. It's usually best to be well below the endurance testing ripple current datasheet rating in your application for long life. Leave the 321 mA rated cap for signal paths in building miniature audio preamplifiers
  3. Even unabused conventional liquid electrolytic capacitors made by the most reputable manufacturers degrade by loss of electrolyte. There is some gradual loss by evaporation past lead seal(s) even when idle at room temperature. Loss is compounded if seals are thermally abused by soldering process and/or chemically compromised by cleaning solvents. With respect to a given seal technology electrolyte loss is accelerated if the internal vapor pressure increases for any reason, such as: - a higher vapor pressure electrolyte formulation is selected to achieve extended temperature operati
  4. The one yoyo I have opened was not easy and somewhat risky to the clear plastic top. Controlled prying between the clear plastic top and the white plastic just below it is needed to break a solvent weld. Tool should be wide enough to spread the force somewhat. Some of the clear plastic may break off and remain welded to the white plastic. Do not pry between top and bottom clear parts, only between clear top and the top rim of the white plastic immediately below it.
  5. Guide to the Macintosh Family Hardware, Second Edition has more extensive power supply specs for the SE/30 on pages 259-260 that relate to this discussion. In particular on page 259 there is a peak load specification for disk seek servo current on the +12 V disk (4A, with certain duration and duty cycle limits and an allowed sag to 11V) and on page 260 there is what I consider a very tight requirement on +12 V sweep: The way I read it is that the + 12 V sweep supply volts will not vary by more than +_10 mV in response to any one load step on +5 V, +12 V disk, or -12 V, while supply rails oth
  6. Needs some experimentation. If two cores are mated there is still a small gap plus chamfer taper of effective cross section at the meeting ends so we can't presume exact equivalence to a single seamless length of powdered iron. The width control has to be able to compensate for variations in DC HV to the CRT (changes deflection factor), variations in flyback sweep voltage, and variations in the total of the 10 uH linearity coil plus the nominal 80 uH yoke (mine measured 80 uH). I suspect .75 inches long alone of the permeability 20 substance would work for me but is likely insufficien
  7. Major correction! This morning I read my last post again and decided to repeat my measurement of resistance which seemed to me to be too high given the wire size. Turns out in going to post yesterday I did a decimal point error. Sorry, here is the corrected post and value: .066 ohms, determined by four terminal measurement of .0657 volts across coil component side solder joints while one amp was flowed thru PC solder side terminals.
  8. .66 ohms, determined by four terminal measurement of .657 volts across coil component side solder joints while one amp was flowed thru PC solder side terminals. Most people with this problem already have perfectly good copper windings on perfectly good coil forms, once that pesky but quite brittle stuck core is removed. One approach is to cut away the exposed form in various ways to allow an intact but stuck core to be grasped and twisted out to be cleaned and reused. Another approach better for already fragmented cores is further mechanical fragmentation by controlled violence. A nai
  9. Measurements of an undisturbed, good and properly adjusted L2 in an SE-30 (with yoke plug disconnected, of course): 25 uH. This unit has a black core, 1 inch long; .6 inches remain outside the copper winding area and .4 inches are inserted into the winding area that is about .550 inches long.
  10. Some time ago prompted by some previous posts on jammed width control cores I started to experiment on a scrap analog board I just happened to have, and very quickly cracked and jammed my core quite badly into many fragments while using the correct size alignment tool. After some appropriate words I set it aside. Today I started examining the situation a bit more and here are some observations. Removing a jammed core is easy if the core is mostly outside the part of the coil form covered by the litz wire coil winding. Carefully longitudinally slit the plastic coil form using a razor bl
  11. SMD multilayer ceramic capacitors are sometimes marked with two digit EIA code for capacitance value. A5=.1 microfarad. See http://my.execpc.com/~endlr/markings.html for SMD ceramic cap markings. Probably these are capacitors, especially if their positions are marked on the PC board with C prefixes followed by unique numbers.
  12. Years ago I had to make a cable to get mine to work. After some research, I found that US patent 5,307,083 had most of the necessary information for the cable, and also contained a very informative theory of operation.
  13. I have only access to a Color 30, not the Color 30HR which has a different video spec. The Color 30 model has a limited video spec, 640x480, 8 bits max pixel depth or 640x870, 4 bits max pixel depth. On the Color 30 board, the memory is four Micron Technology MT42C8128DJ-8.
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