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Thread: Jaycar Phoenix card reader voltages too high?

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    Default Jaycar Phoenix card reader voltages too high?

    I have just constructed a Jaycar MkII Phoenix card reader for my HTPC and would like feedback regarding the test voltages I'm measuring. In the following list the first figure is what Jaycars instructions say the voltage should be, followed by my measurements:

    Between pins 7 & 14 on IC2 and IC3 - 5.0 (6.5)
    Pin 2 of IC1 - >8.7 (12)
    Pin 6 of IC1 - At least -7.8 (-11.5)
    Cathode of D3 - >15.6 (22.1)
    Cathode of ZD1 - 13 (17.2)

    These measurements were taken with jumpers on 3.5795MHZ and Phoenix, switch in, powered by hard drive connector, no card, and serial cable not connected. No mods. Tried installing in 2 different PC's - same results. Are these higher voltages likely to be a problem? (Would prefer not to cook my card). There were 2 brass pins left over when finished which I could find no reference to in the instructions - are they relevant? I have also noticed that voltages are slightly lower when first powered on, rising slightly with time - is this normal?

    I'm an electronics novice (1st project) so any advice would be appreciated, including tests I could perform. Is there a blank card test I could try before risking my sky 45xx card? Can supply photos if required
    Last edited by stiffwin; 03-04-10 at 07:07 AM.



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    Have a search for jaycar buy GW1. There are lots of informative posts. There was one that talked about the holes drilled for the voltage regulator cutting through the tracks which is worth a look.
    I would start by double checking that you have all the components in the correct location and get a magnifying glass to make sure all the solder joints llook good. Also make sure tracks are not shorting to others with splashed solder etc.

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    Thanks Leroy - so these voltages would be problematic?

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    I'm no electronics expert either, but my voltages between pins 7 and 14 are 5.07. So I think yours are probably too high.

    The only difference is I use a 9v plugpack.

    Don't know about the pins near the power area. Maybe test points.

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    Quote Originally Posted by stiffwin View Post
    Thanks Leroy - so these voltages would be problematic?
    I reckon you have a problem somewhere as those voltages are too high.

    Leroy
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    Zd1 according to the circuit diagram is a 13V zener to earth.
    If this is correctly fitted in circuit you should not get any more than 13v on the cathode. Make sure that the anode does measure at earth potential.
    Joys of building a project!

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    I have followed GW1's troubleshooting guides (from the austech forum) to the best of my ability but no change. Does anyone have any suggestions - I would be happy to pay someone to sort this out (mind you, I'm in Hamilton, NZ) - otherwise I might have to start from scratch with a new kit.

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    Did you check the 13V Zener diode?
    Make sure you have the 13V diode in the correct position and you have not put a normal diode here instead.
    As I said the cathode should not be more than 13V if if the correct diode is fitted.

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    Yes the Zener diode is the right one and correctly positioned, and the voltage at the cathode end is around 17v
    Last edited by stiffwin; 06-04-10 at 07:33 AM.

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    polarised caps all round the right way ?

    some of those recent boards have multiple holes for the transistors leading to shorting if the inner most ones were used with some careless soldering,.. checked all those ?

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    What multimeter are you using? Is it battery operated?
    Check some New batteries with your meter ie 1.5V, 9V also your 12V battery in a car. Post your result here.
    I am thinking of buying a Jaycar programmer as I am not having much luck with Elvis!

  • The Following User Says Thank You to ozvic For This Useful Post:

    stiffwin (06-04-10)

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    Thanks for all your responses guys - esp. ozvic who pointed me in the right direction. My multimeter reads about 28% too high! Have just purchased a new one and all voltages are spot on. Thanks once again!

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