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Dynasty 200SD low buss voltage

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  • jjohn76
    replied
    Originally posted by paulstef View Post

    I had to register on this forum to do one thing. To say THANK YOU!
    I was in the process of reverse engineering that PCB myself and was wondering why the flyback was only working occasionally.
    You mentioning that it needs Vbus operational was very helpful.

    It lead me to check where the 810V goes from RC1 on PC10. Found the first 750k resistor, part of the voltage divider of 3x750k, to be open circuit.

    You just saved me a couple of hours of troubleshooting. Thanks a lot!
    Glad it worked out!

    Leave a comment:


  • paulstef
    replied
    Originally posted by jjohn76 View Post
    So this flyback circuit doesn't have an oscillator or some way to routinely turn mosfet Q1 on and off. It basically turns it on when four conditions are met, and turns/keeps it off when any of the four conditions are not met. It does this through four feedback loops.

    2. DC buss voltage feedback. This is in the middle of the schematic, controlled by U2 on PC10. It only enables the mosfet to turn on when the DC buss voltage is at the designed 810V (input circuit is working properly).

    ​​​​
    I had to register on this forum to do one thing. To say THANK YOU!
    I was in the process of reverse engineering that PCB myself and was wondering why the flyback was only working occasionally.
    You mentioning that it needs Vbus operational was very helpful.

    It lead me to check where the 810V goes from RC1 on PC10. Found the first 750k resistor, part of the voltage divider of 3x750k, to be open circuit.

    You just saved me a couple of hours of troubleshooting. Thanks a lot!

    Leave a comment:


  • Noel
    replied
    Jon, I understand. lol...I'm trying to get this Kia running and it's sucking my will to live. I've got the scanner apart and in arms reach but haven't completed that 3 pin repair or jury rigged a repair. But I'm on it. I have a plan for the jury rig solution but was hoping to avoid that route by driving across town, I just haven't gone in that direction. Road construction due to LRT improvements makes that trip a hassle. No pressure and for certain no problem.

    Leave a comment:


  • jjohn76
    replied
    Noel, I haven't had the time to draw out the schematic, but will soon.

    Leave a comment:


  • Noel
    replied
    Just an update for those reading. I haven't got new pins yet. But I'm working on it, I'm in the planning stages. I'm no quitter, but with the age of the scanner, some might say maybe I should? I'll be back.

    Leave a comment:


  • Noel
    replied
    Originally posted by jjohn76 View Post
    Does the quickstart with the battery work by pressing the button with the 9V attached? I am guessing the LCD screen lights up and displays something? I have put together a bit of the circuit, and for this one will try to use a schematic capture like eagle (it has a free version).

    If you have the free time,I found a site a long time ago with animated representations of a lot of analog circuits. It definitely helps visualize the voltage and current. Half way down is a link to a bunch of different circuit examples.

    http://falstad.com/circuit/

    Jon
    Nope, no quick start. Nothing. And to make matters worse, on re-assembly I folded the three little pins off the Y/N terminal. I'll take it apart and see if they can be pushed out and if enough pin leg remains to plug it back in? As it is I haven't tried hooking to a vehicle to see if it powers that way at all, depending on how it goes with the pins I'll let you know further tomorrow.

    That link was pretty cool stuff. I saved it to my fav bar so it doesn't get lost. Thanks Jon.
    Last edited by Noel; 10-31-2019, 10:59 PM. Reason: Got the pin stubs out, but the terminal they broke off of has to be repaired.

    Leave a comment:


  • jjohn76
    replied
    Does the quickstart with the battery work by pressing the button with the 9V attached? I am guessing the LCD screen lights up and displays something? I have put together a bit of the circuit, and for this one will try to use a schematic capture like eagle (it has a free version).

    If you have the free time,I found a site a long time ago with animated representations of a lot of analog circuits. It definitely helps visualize the voltage and current. Half way down is a link to a bunch of different circuit examples.

    http://falstad.com/circuit/

    Jon
    Last edited by jjohn76; 10-31-2019, 10:34 AM.

    Leave a comment:


  • Noel
    replied
    Originally posted by jjohn76 View Post
    Good stuff Noel, I'll see if I can trace out the schematic. The good news is it is not as complicated as I had originally said - no flybkack or multiple power supplies. I think I read somewhere that when you push the red button, it's a quickstart on the battery, otherwise plugging it in gets it running?
    I'm doing my best to keep up Jon. Going by memory from when I purchased it, it wouldn't do the quick start off the battery. It would light up when the button was pushed but go blank when released, again going by memory. At the time I assumed it was the battery or the button as the issue. Attached to the vehicle it did link to the truck it was briefly attached to, but since I didn't know how to use the tool, and it wasn't my truck it was connected to, I didn't push y/n buttons, or scroll through the functions or do further set up.

    Installing a new battery, it failed to produce a start screen but I didn't try to connect recently to a vehicle either? With the weather warmed up to +6 from the previous days -6, I'm set to be doing a timing belt install on the Kia.
    I'll reassembly the unit, try again to see if the start up screen lights up and hook it up to a vehicle and advise on the findings.

    Click image for larger version

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    I should have included this picture of the display board. I'm not sure if it's relevant or not to solving the problem or the issues? But knowing it did at one point display information, my assumptions it was a powering up issue, I failed to include or address the possibility of it being part of the problem?

    Click image for larger version

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    Makes for a nice pile to display doesn't it?

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  • jjohn76
    replied
    Good stuff Noel, I'll see if I can trace out the schematic. The good news is it is not as complicated as I had originally said - no flybkack or multiple power supplies. I think I read somewhere that when you push the red button, it's a quickstart on the battery, otherwise plugging it in gets it running?

    Leave a comment:


  • Noel
    replied
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    Hope this helps the cause and they are clear enough to trace with. If not I'll be happy to take them again. No pressure Jon. I'm sure you have a full plate of your own and you have offered plenty of assistance already on an off topic to the thread. Which reminds me, I said I was going to do that?
    Last edited by Noel; 10-29-2019, 11:28 PM.

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  • Noel
    replied


    Click image for larger version

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ID:	603869I'm going to have to put a bit more effort into this. Not only is the LCD not as bright as I thought for a white bright background, I couldn't hold things steady enough free handing it and taking a picture at the same time. Presently the battery is on the charger doing it's thing.

    "The easiest way I have found to trace leads is to track them as far as I can, make a guess at where they go, then confirm with the audible continuity tester on my multimeter."

    Holding the board to a light... That was a trick I never knew? Maybe I'm the only one who never knew you could but I do now!
    I like the way your thinking Jon. Yea, the red thing is the switch push on/off.

    I do feel bad putting you through the work. But I have an idea that will improve my pictures so if you hang tough, I'll make things easier on you. Lol.

    "U7 is an operational amplifier"

    So t
    he little monster has a name. Good stuff. I should start a list. Everyday a new word, new thing to learn.

    https://www.bing.com/videos/search?q...36D1&FORM=VIRE

    Holy fish...I need to revise my chances 10/90. This is riding on your shoulder that's for sure. It's a lot to ask Jon, you sure your up for this? It's not like it's sitting in front of you? To make things worse, you have to instruct me to do it once you figure it out?

    Next posting better and more pictures.




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  • jjohn76
    replied
    Noel, would you be able to take a picture of it with the light shining through the back of it? It's easier to compare the traces that way. I haven't been able to find the pinout for the scan tool connector, but I can see at least the ground and power coming from that. The diodes are connected to a number of signals, so we'll see where they go. That mosfet looks to just turn on the scanner when power is connected, so we'll see what connects to the 5V regulator input.

    Another update - what is that red block? Is it a button/switch?
    Last edited by jjohn76; 10-29-2019, 01:21 PM.

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  • jjohn76
    replied
    Noel, I'll find some time soon to study the board and draw a schematic. The easiest way I have found to trace leads is to track them as far as I can, make a guess at where they go, then confirm with the audible continuity tester on my multimeter.

    U7 is an operational amplifier, which basically compares two input signals/voltages, and provides an output based on those inputs. Depending on if/how the output is connected to the inputs, it can act anywhere from a switch, a voltage divider, or a lot of other functions. When we get it traces out and put on a schematic, I can walk you through what it does in this circuit. The silver diode to the right of it is a zener diode, which is typically used to make a steady voltage. It will typically have about .5V forward in one direction (diode tester), and will measure open loop in the other direction until the voltage across it is equal to the zener voltage, then it will conduct.

    The resistance to worry about on the voltage regulator is anything very low. It's good your resistance measurements increased the longer you kept them connected - that shows your capacitor is working. When we get a schematic, it will be easier to troubleshoot.

    Edit- with a better look at the diode next to U7, it does not look to be a zener diode. I'll see how much of the schematic I can draw later today.
    Last edited by jjohn76; 10-29-2019, 11:17 AM.

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  • Noel
    replied
    Originally posted by jjohn76 View Post
    Noel, it doesn't look like any power is getting to your 5V voltage regulator, which means most of your controls aren't getting power. Can you trace the leads back from the input to the voltage regulator? Also, what resistance do you get across the input and ground, as well as output and ground, on the voltage regulator without a battery connected? Also, is that a power switch on the right side of the case? It looks like it has a blue, black and red wire coming out of it. Does the blue wire go to the voltage regulator?
    Originally posted by jjohn76 View Post

    i will try to find time later today to compare the top and bottom of the board to see where to test next.

    You also likely have a flyback converter on that board (orange box should be the Flyback transformer, you can see the diodes labeled FB1,FB2,FB3,...). It's been a dozen years or so since I messed with the OBD protocols, but remember they used both positive and negative voltages to limit noise issues.

    I knew at some point things could get complicated. Guess this is that point.

    "Can you trace the leads back from the input to the voltage regulator?"
    I'm not crystal clear on what it is your asking Jon? I will assume it's can I figure out where the power is distributed from the point it enters as 9V from the red and black location on the board to the voltage regulator? Yes. But I'm confused by it. I also haven't yet clearly identified it's path or branches.
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ID:	603849 U7...what's that thing Jon? What does it do? The reason I ask is that in trying to map the board the positive(red) from battery seems to go under it and feed next to it what I assume are what? Are they diodes? I ask because I think the middle is a dud? It reads open in both directions?

    My present capacity to grasp this is limited. As I direct my focus to understanding what each of those components is, how it functions, operates and controls, what and where, with a why, It becomes clearer.
    I'm of the understanding the 9V provides an initial power up to light the screen and display a start up, but the scan tool relies on vehicle power to operate.
    It was not lighting up or starting up. I always assumed it was the micro switch in that red button being the problem or what supplied it with power failing.

    "Also, what resistance do you get across the input and ground, as well as output and ground, on the voltage regulator without a battery connected?"

    I'm assuming input left leg, out put right leg, GND center leg.
    Doing so I'm getting conflicting results depending on the scale and duration of being attached.
    On 20M, negative to center leg, positive to input left leg, 0.01
    On 20M, negative to center leg, positive to output right leg, 0.00

    On 2M, negative to center leg, positive to input left leg, 0.01 and shows a slow increase to 0.35 at which point I said enough.
    On 2M, negative to center leg, positive to output right leg, 0.02 .

    "Also, is that a power switch on the right side of the case?"
    No, my understanding is that it's a scrool function.It plugs in J7. The big red button is on and off.There is also s Yes and No touch pad that plugs in .J6

    "Does the blue wire go to the voltage regulator?"
    Yes. J7 Red left, blue center, black right. I show continuity from the blue wire, center of the three to the center leg.
    J6 has the same three color wires same locations viewed from top to bottom. Black shows continuity to the output right leg. No continuity at all from the blue wire to the voltage regulator.

    If I messed up, did something wrong, correct me Jon. I asked about U7 and what it does. If those three were diodes? The mapping, I'm trying to get it. I don't expect you to do all the work either, but I'm looking forward to another lesson in learning.

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  • jjohn76
    replied
    Noel, it doesn't look like any power is getting to your 5V voltage regulator, which means most of your controls aren't getting power. Can you trace the leads back from the input to the voltage regulator? Also, what resistance do you get across the input and ground, as well as output and ground, on the voltage regulator without a battery connected? Also, is that a power switch on the right side of the case? It looks like it has a blue, black and red wire coming out of it. Does the blue wire go to the voltage regulator?

    i will try to find time later today to compare the top and bottom of the board to see where to test next.

    You also likely have a flyback converter on that board (orange box should be the Flyback transformer, you can see the diodes labeled FB1,FB2,FB3,...). It's been a dozen years or so since I messed with the OBD protocols, but remember they used both positive and negative voltages to limit noise issues.
    Last edited by jjohn76; 10-28-2019, 06:22 PM.

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