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Showing content with the highest reputation on 06/24/2020 in all areas

  1. smoking some grass fed meatballs for lunch
    2 points
  2. Yup, that's how I see it, we don't have the information to know if this new ARS chip that would be implemented on the new iMac would be a transitional chip towards a more developed, affordable... one which would revolutionize personal home computing, or eventually a very good one outperforming current Intels. Or not, just a chip offering a better cost/effective more profitable option for Apple, which for being in "development" phase might be buggy and troublesome compared to the current Intel offerings that have been working on computers for more than a decade. Would Windows make something to compatibilize these new chips? Not that I'm using any Windows based apps on my Mac, but still compatibility is desirable. On the other hand I'm with Hi-Wire that the current iMac line is being outperformed by more affordable options mounting better and more energy and heat savvy options. An intermediate upgrade of the iMac line keeping Intel architecture with better performance/price graphics and more affordable SSD, perhaps more RAM, would be my preferred option. Again we lack the information.
    2 points
  3. Another KGSSHV Carbon lives! Thanks to @sorenb @Kerry @simmconn for the help on bias voltage. I used 2 x 120v 0.5W and 2 x 130v 3W in the end. The 0.5w parts work well. Next steps: cable management, re-case, increase heatsink size.
    2 points
  4. Out of the Blue – Electric Light Orchestra Relentlessly cheery 🌞
    1 point
  5. Yeah. You've got sharp eyes sir!
    1 point
  6. None? That's why I was confused by Mr. Chalk's comment.
    1 point
  7. The issue for me is the lack of information. If the new 27" iMacs are going to be released by early 2021 and will be using Intel processors, I'd wait. But if they're going to sport the new Mac processors I might prefer sticking with a current Intel machine. I wouldn't like being a guinea pig for the new processors paying full Mac prices.
    1 point
  8. Spent the evening trying to figure out why my mom's car died in the middle of her driving it. I managed to track it down to the fuel pump, which was so much fun to actually replace, but it got the car running again.
    1 point
  9. GR78xx build notes: Writing direction on the opamp and voltage reference match the writing direction on the pcb I suggest checking the led orientation with a multi-meter in diode test mode, finding out which way round the multi-meter leads need to be to make the diode light and then marking either the positive end of the led with a red pen or the negative with a black pen whilst holding the led with twisters - if you don't hold the led with twisters it has a nasty habit of sticking to the pen tip. The leds face opposite directions. Positive and negative ends are marked in the picture with red and black lines respectively. All transistors are shown with their case markings. Its a good idea to solder the leds in first and then check. D2 has the end closest to the Vin pins connected ground and so its easy to check its orientation is correct, the other led is opposite orientation. The DN2540 is a depletion device so if you measure resistance between pins, two of the pins will appear to be shorted - this is normal and shown on the picture. The tab is also electrically connected to the centre pin... The top left pin of the hn4a51j is also connected to the bottom middle pin on the ocb and will therefore also measure as a short. The pmsta devices have 3 digit case codes the first digit being the place of manufacture, the kst devices have two digit codes. Be aware Both the pmsta42 and kst42 have codes 1D but the pmsta42 has a t or other letter before the 1D for the manufacturing location. voltage ref should have 10V between pins 4 and 6 If you test the board by itself it must have capacitance connected to the output in excess of 20uF in order to regulate and not do strange things like increase the output voltage when the load increases. When setup for 15V output, input voltages bellow about 1.7V should result in very little current draw <1mA and no leds lit . At around 1.7V input D2 show glow dimly and increasing the input voltage should result in D2 glowing brighter, the current draw increasing and the output voltage increasing. When D2 is fully bright the current draw should be about 10mA. At about 17.5V input D1 should begin to light . Increasing the input voltage further will make D1 brighter and the current draw increase towards 10mA current the draw when the led is fully bright. At around 18.3V input the output should stabilise at around 15V and increasing the input voltage further should have no effect on the output voltage or current draw. The second 78xx I built required 0.2V more to regulate fully despite having a 8mV lower output. Load testing Expect approximately a 23mV decrease in output for each 100mA of load current drawn from the gr78xx. At 200mA the components on the board should be warm but easy to touch and leave your finger on. The MJW211 should also be a little warm. NOTE the metal tab of the MJW is live so don't short it to something. Voltage drop under load test, no heat-sinking, MJW211 close up against the pcb, 18.3V input. The drop in output voltage is the same using a 47uF output cap as 220uF. 100mA 23mV drop 200mA 46mV drop 300mA 69mV drop 400mA 93mV drop 500mA 116mV drop (note tab of mjw gets too hold to touch for more than a moment after a few minutes of this load. heat-sinking recommended) The second 78xx I built had voltage drops within 2mV of the first. The voltage drop under load is a bit more than a traditional 7815 to-220 voltage regulator under the same conditions. Removing the load results in the output voltage of the gr78xx going back to within 1mv of the original no load output almost instantly, even from the hot 500mA load. the voltage drop is fairly linear with load. Otuput voltage drift under constant load as the device heats up or cools down is very low. LED direction verification for gr78xx lower led D2 multimeter in diode check mode red probe on top of led black probe on bottom (as indicated in photo bellow) you should get about 0.89V drop led will not light. probes reversed meter should say OL upper led D1 multimeter in diode check mode black probe on top of led red probe on bottom (as indicated in photo bellow) you should get about 1.66V drop led will light. probes reversed meter should say OL 79xx build notes All polar caps, Zener and LEDs are in the opposite orientation to the 78xx, All resistors are in more or less the same positions and orientations as the 78xx, all transistors that are xx42xx become xx92xx and visa versa. NOTE in the BOM Q6 and Q4 appear to be the same on both the 78xx and 79xx however, on the silk screen the physical positions of Q4 and Q6 swapped in all other cases the transistors change in the BOM rather than the silkscreen designations moving. The opamp and LT voltage reference are in the same orientation as the 78xx. The HN4A51J becomes HN4C51J and the MJW211 changes from 94 to 93. All positions that hold a KST device continue to do so and the same is true for the PMSTA. Only the type of device swaps from NPN or PNP i.e. from kst42 to kst92 and visa versa or pmsta42 to pmsa92 and visa versa. The 79xx has similar load behaviour to the 78xx. LED direction verification for gr79xx lower led D2 multimeter in diode check mode red probe on bottom of led black probe on top (as indicated in photo bellow) you should get about 0.89V drop led will not light. probes reversed meter should say OL upper led D1 multimeter in diode check mode black probe on bottom of led red probe on top (as indicated in photo bellow) you should get about 1.66V drop led will light. probes reversed meter should say OL
    1 point
  10. And how many cases has there been of long term architectural transitions? 2? That’s not exactly a statistically valid sample, especially considering how different today’s climate is compared to the first two. I’m not saying it won’t happen, I’m just saying we don’t have enough information to interpolate a b-spline curve.
    0 points
  11. I’m with him. I doubt even Apple can predict whether this is a long term phased replacement or just a phase. I certainly won’t be the guinea pig. I realize you all want to throw predictions out there, but that’s all they are, predictions.
    0 points
  12. Electric fuel pump. Fortunately I didn't have to drop the tank, but I did have to take out the entire back seat and trunk liner, then work through an access hole that some galaxy brain at GM made about half an inch too small for the pump and locking ring to fit through.
    0 points
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