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Post by ulysses31 on Aug 1, 2008 8:29:33 GMT -5
the problem is that it has started making some very strange buzzing noises.... these seem to originate from the MAX202 chip which also gets very hot! do i need to buy a new chip and resolder it (i hate smd soldering) or is it something else. and trying to program the pic chip kept coming back as error. saying that i should program it as it was not sending any serial data and it was in a reset state!
any help would be appreciated
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Post by jsaily on Aug 4, 2008 10:50:54 GMT -5
Hi, do you have a multimeter to check if there are any short circuits on the board ? Please check the MAX202 pins especially. If you can't find anything, you can send it back to me for IC exchange.
This is the first one which has failed from tens of units.
EDIT: It may be the charge pump on the MAX202 which is making the noise. Check especially the 100nF capacitor connections around the IC. Also make sure you don't have short-circuited outputs!
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Post by ulysses31 on Aug 5, 2008 9:59:54 GMT -5
jsaily check your pm
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Post by jsaily on Aug 8, 2008 11:05:06 GMT -5
ulysses31, I got the card today and ran all my production tests on it. No faults found, and no noises or any components getting hot. Must be a problem with your serial cable! The cable must not be a null-modem cable but a straight cable.
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Post by ulysses31 on Aug 8, 2008 14:45:29 GMT -5
Now I am confused serial cable is a home made 3 wire job all pins connected as they should. anyway check your PM
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Post by jsaily on Aug 8, 2008 15:28:36 GMT -5
Hmm.. are you sure the voltage is 5V to the 1541-III-DTV board? I guess the tolerance for MAX202 is less than for the PIC. Everything worked fine with 5.08 volts ;-)
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Post by ulysses31 on Aug 8, 2008 16:02:57 GMT -5
the voltage is 5.0v from a 7805 regulator and a few capacitors using a sega megadrive 9v psu for input
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