Sencore LC-102 Part 6 - A Quick Update

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  • เผยแพร่เมื่อ 28 พ.ย. 2024

ความคิดเห็น • 30

  • @poormanselectronicsbench2021
    @poormanselectronicsbench2021 ปีที่แล้ว +3

    Glad to see you made good progress! The back EMF snubber diodes seem to be a great idea to prevent future issues with the IC11 chip, it's an inexpensive mod that should in no way affect any other functionality. My unit has one quirk when using the Leakage/Ohms function, as it seems to be accurate enough when set to leakage, but, when set to ohms, on anything fairly low in resistance it just displays "0 Ohms", but if measuring with the ESR function it gives a fairly accurate measurement comparable to the actual DC resistance. I noticed in the user and service manuals, that, there are no specs' as to the range of "Ohms" for the resistance measurement function, nor is there any mention of a specific cal procedure for the ohms measurement function, so, seeing that I have a bunch of ways to measure resistance, I am not going to sweat it.

  • @radio-ged4626
    @radio-ged4626 ปีที่แล้ว +1

    I'm loving this series. The collaborative effort and feedback from other viewers and your ability to interpret the circuit design, explain what has gone wrong and what you think may have gone wrong together with minor circuit improvements along the way keeps me glued to the screen.

  • @davids4610
    @davids4610 ปีที่แล้ว +2

    The saga of the Sencore continues!

  • @williamsquires3070
    @williamsquires3070 ปีที่แล้ว +3

    The unit could really stand to have a backlight for the LCD displays… or retrofit some 7-segment LED displays for better visibility.

  • @mbwatson1000
    @mbwatson1000 ปีที่แล้ว +1

    Fantastic work and persistence, Tony. Definitely the relays needed back EMF protection for the drivers. It sounds like the MCU was exposed to electrical stress which caused its port outputs to fail. Given the number of other failures you have found, maybe that is not a surprise. Keep going, you will get there.

  • @ebones6957
    @ebones6957 ปีที่แล้ว +3

    Wonderful content…it ‘s like binge watching a Netflix series

  • @rlgrlg-oh6cc
    @rlgrlg-oh6cc ปีที่แล้ว +1

    Great progress! Just wanted to mention that an analog switch feeding a cap to ground followed by a voltage follower is a classic "sample and hold" circuit. This is grabbing the initial voltage across the cap due to the applied current, before it starts charging, which is how they measure the ESR.

    • @andymouse
      @andymouse ปีที่แล้ว

      Yes, very useful !

  • @Dutch-linux
    @Dutch-linux ปีที่แล้ว +1

    Take it easy Tony do what you got to do first... with that said I seen a few phillips chips in there .... check those as phillips was crap with making ic's very high failure rate... Love your video's always learn something so thank you for what you do .

  • @pcwrangler09
    @pcwrangler09 ปีที่แล้ว

    Great series. I will be referring to this a lot for my own repair. Thank you!

  • @christiantreldal1585
    @christiantreldal1585 ปีที่แล้ว +2

    Hi again Tony 9:30 careful now 74cxxx and 74hcxxx dont't have the same logic levels as I told you before. 74c= 0 max 1.5v, 74hct= 0 max 1.35v. It's not a lot; but it has hit me several times. Keep up the good work.

  • @M0UAW_IO83
    @M0UAW_IO83 ปีที่แล้ว +1

    Used to confuse the hell out of me when I was tinkering with 803x chips.
    PSEN is to select internal or external program memory, ALE is to enable the latch which demuxes the address/data bus for when you're using the external :)

  • @s8472-k8i
    @s8472-k8i ปีที่แล้ว +1

    Clean the fuse contacts behind the BNC connector. This can cause problems with lead zeroing

  • @davidv1289
    @davidv1289 ปีที่แล้ว

    Excellent progress. The snubber diodes on the relays are a good idea, I'm surprised they weren't part of the original design. Seems like they were relying on the intrinsic diode in the MOSFETs to handle the back EMF. The lead short test failing is a good clue to resolving the ohms/esr problem. Regards, David

  • @justinmijnbuis
    @justinmijnbuis ปีที่แล้ว +3

    Didn't those relays have a LED attached when you got the unit? Maybe that was an EMF mod.

    • @ElektrikaCo
      @ElektrikaCo ปีที่แล้ว

      Back emf diodes are hooked up in reverse with respect to the coil. LED indicators were same polarity.

  • @paulvanderwielen8173
    @paulvanderwielen8173 ปีที่แล้ว

    as the circuit is fairly dynamic, it will be hard to do solid measurements, I would suggest to use a 3 channel scope measurement on each of the reed relays, chan #1 on contact input, chan #2 on output of contact, chan #3 on coil to serve as trigger, then do a single shot measurement on relay activation and then see if the relay doesn't have any contact resistance which could be cause of your error 4, alternative way to measure relays static is to pull the mcu and put power on the output associated with te relay and measure it dc resistance, this may differ from the dynamic behaviour

  • @Homer19521
    @Homer19521 ปีที่แล้ว

    When you do get it completely working, you can add some lighting to those LCD's as the frosting on the cake. 👍

  • @electronics_geek
    @electronics_geek 5 หลายเดือนก่อน

    At first it seemed to me that I wanted such a device. But now I clearly understand that I DO NOT want 😁

  • @t1d100
    @t1d100 ปีที่แล้ว

    Excellent. Do you keep field notes? Handy for remembering where you left off...

  • @tomb8185
    @tomb8185 ปีที่แล้ว +2

    Did you happen to clean those toggle switches on the front panel? Have chased my tail many times before and turned out to be poor contact on a switch... Good luck!

  • @andymouse
    @andymouse ปีที่แล้ว

    Cheers !

  • @Area51Corsair
    @Area51Corsair ปีที่แล้ว

    Hi Tony, did you go for the 17 release version of the EPROM in this video. Did you try the old 13 release version with the new microprocessor ?

    • @xraytonyb
      @xraytonyb  ปีที่แล้ว

      It is currently running on V17. I also tested it on V15 and it seemed to work as well. I could not tell any difference between the two.

  • @stintus1
    @stintus1 ปีที่แล้ว

    I remember Sencore had a problem with those and the replaced mine with the 103

  • @jimomertz
    @jimomertz ปีที่แล้ว

    I don’t know this machine, but don’t you have to select a capacitor type with the buttons on the left? Maybe those are used for ESR or leakage tests?

  • @NICK-uy3nl
    @NICK-uy3nl ปีที่แล้ว

    This machine is an early example of a MIXED analog-digital circuit design and all the problems associated with it. Without a proper description or block-diagram of the MCU control firmware it is going to be very difficult to repair. For obvious reasons, manufacturers never release firmware source code or specs to protect their IP

  • @jbboating3268
    @jbboating3268 ปีที่แล้ว

    The Error 4 turn out to be a dirty contact on the white relay. Look at the email I sent you. Hopefully that will cure that problem.
    Jay

  • @smcic
    @smcic ปีที่แล้ว

    Hi everybody

  • @jdmccorful
    @jdmccorful ปีที่แล้ว

    Back on track! I can wait for when you have more time. Nice work, enjoyed;thanks.