Date:   8/9/2009 10:34:57 PM ( 15 y ago)
Hits:   71,303
URL:   https://www.curezone.org/forums/fm.asp?i=1470153

"I have tested at the CS jack, there was no continuity, however when plugged the cable in and tested the continuity it still has no continuity, surely when the jack cable is plugged in it should have continuity through the ends of the cable in order for it to work???????????"

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No continuity is good.

But no continuity with plug in is a concern.
Make sure to touch the alligator clips, from CS plug, together to make a closed circuit. Measure this directly on the jacks contacts (- to avoid the lamp. You can check each component separately, then from ground to jack contact).
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"I changed those top two schottky’s, i also swapped the 10uf 50v cap on the left for a 35v and changed the middle cap for a new 10uf 50v, i have re-tested and now i am getting 8.7 v at each schottky, same all the way down, any ideas what to do next, theres definitely no shorts across solders i really checked that, is there anywhere that i missed where i should have drilled holes and made gaps to separate components."

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Try to feel the components temperature to make sure nothing is getting cooked (very hot - that would indicate short somewhere or miss-wired circuit)
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"Its very difficult to get those chips specifically unless i order them from America, or do u think i could pay you to send me them over? Its thats too much trouble then don’t worry its no problem."

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http://www.mouser.com
will do better and faster job at shipping then me.
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"If there could be anything else that could be causeing that problem then what could it be, or what else could i also try to get this voltage up and alternating.
If you cant think of anything else then i will take some clearer pictures from the back and send them to you, let me know what you think."

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I still like to see the back in the clear picture - I want to make sure that all soldering points are solid.
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"This might help you to knoe what the problem is........... when i first turn on the battery, if i quickly read the voltages then they are all crrect and as i move down the rectifiers it gets lower just like you stated before, the thing is also that from that point onwards they immediately start to go down and down more in volts as i hold the tester on each 1 i can see the voltage is like its being drained down, until they reach 8.7v and then they all stay there, i you may know what this is????????"

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Now this is important information. Your 7660S is freezing up (possible thermal protection) - it stops doubling the voltage - that is why you end up with 8.7V which is just what your 9V battery pumps in with voltage drops from shottsky rectifiers.
If this indeed is thermal short then there must be a reason for this:
A) The chip does not handle that kind of voltage (I doubt that, max rating is 160 mA, but so is 7660D)
B) There is too much current pulled through it. For too much current to flow there must be cross-connection to ground in the active circuit.

If none of the above is true, then you should replace it if possible with the 7660D chip (7660D handles max 180 mA).

>>> Can you tell me the full name of your chip again? <<<

Other chips that will work and worth trying:
MAX1044
TLC7660CPA
LMC7660
NJU7660D
I found this chip "LT1054" is also recommended as 7660D replacement at one forum, but I have not used it - so I cannot vouch for it. (do not use "LT1054L" that is low 7 volts input only version).

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To test the Beck's circuit separately disconnect wires from the step up circuit and connect 3x 9V batteries connected in series to plus bus and minus bus. This will allow you to see if your Beck's circuit functions correctly with out the 33V step up circuit - this should get you by until you receive the replacement chip for the step up circuit.

Gill
 

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