problem with 6131nw

asterix · Post by **asterix** » Fri Jun 02, 2006 10:20 pm

i have a problem with my 6131nw. it will only work/ function when connected to pc using paraller port. when it's running on batteries i get no response from remote. comunnication with ir.exe is ok. i can download - upload with no problems.
i tried replacing new batteries with old but still no response.
any ideas?

thank you

johnsfine · Post by **johnsfine** » Sat Jun 03, 2006 6:15 am

How was it modified for JP1.

It sounds like something is shorted to the reset signal.

asterix · Post by **asterix** » Sat Jun 03, 2006 9:12 am

it's modified with mouser Part# http://www.mouser.com/index.cfm?handler ... deid=57989

it works fine as lons as remote is connected to pc (reset 981 works fine- -four blinks, comunnication with ir.exe is ghood, upload/download works fine too)

but when i unplug remote from pc i have no response from remote (led not blinking at all when pressing the buttons.

thank you

asterix · Post by **asterix** » Sat Jun 03, 2006 9:16 am

johnsfine wrote:How was it modified for JP1.

It sounds like something is shorted to the reset signal.

also, i have made my own parallel cable (2 x 1k resistors , 1 x 1n4148 diode, pins 1+2 are bridged)

johnsfine · Post by **johnsfine** » Sat Jun 03, 2006 11:10 am

I meant the reset signal that is one of the six JP1 pins (forget which at the moment).

With the JP1 cable disconnected, that signal should float and the chip is designed to see a float as high (the signal is active low, so high means not reset).

With the JP1 cable connected, the PC controls the signal, setting it low during comm to the EE, and high otherwise.

If there were a high resistance path from reset to ground introduced by accident while modifying the remote, that would give the symptoms you describe. With JP1 the PC overpowers that problem and forces reset to the right state. Without JP1 connected, reset goes low freezing the micro in the remote.

I can't think of any other theory that fits what you describe.

I don't know what extra parts or test equipment (volt meter, etc.) you might have, so I can't tell you the best way to test this theory.

Post by **The Robman** » Sat Jun 03, 2006 11:24 am

johnsfine wrote:I meant the reset signal that is one of the six JP1 pins (forget which at the moment).

It's pin 5.

johnsfine wrote:If there were a high resistance path from reset to ground introduced by accident while modifying the remote, that would give the symptoms you describe.

GROUND is pin 3. So, start by checking for a short between pins 3 and 5.

asterix · Post by **asterix** » Sat Jun 03, 2006 12:18 pm

thank you guys. i do have a multimeter so i will check a short in between pins 3 and 5.

last night i did check voltege going into eeprom (when running on batterie) i could not find anything abowe .7V) it that normal.

100ohm resistor is ok.

thank you

johnsfine · Post by **johnsfine** » Sat Jun 03, 2006 1:43 pm

If it were a direct short to ground, then it wouldn't work even with the PC pulling pin 5 high.

So I was guessing a short to something else that is normally low or some form of partial short to ground.

I'm not sure what the resistance between pins 3 and 5 ought to be.

More interesting may be the voltage between pins 3 and 5 when you try to operate the remote without the PC connected. If pin 5 is nearly as high as battery voltage then my theory is wrong. If it's under 1 volt, my theory is right. In between, who knows.

underquark · Post by **underquark** » Sat Jun 03, 2006 1:58 pm

What if the battery juice isn't getting to the remote but it's working when hooked to PC by drawing current from the port? That would explain why "replacing new batteries with old but still no response" (shurely a typo) occurs.

asterix · Post by **asterix** » Sat Jun 03, 2006 2:28 pm

ther was some resistance between pins 3 and 5.
i did a touch -up on eeprom on pads 5-8. noe it's workink ok.

thank you guys for all your help

Post by **The Robman** » Sat Jun 03, 2006 5:59 pm

EEPROM pins 5 and 6 are the SDA and SCL and the next pin over (pin 7) is grounded, so I guess the short might have been with pin 7.

asterix · Post by **asterix** » Sun Jun 04, 2006 10:34 pm

there was a short between pins 1-4 (ground) and pin 6

Post by **The Robman** » Mon Jun 05, 2006 6:14 am

I doubt that the short was physcally between pin 6 and pins 1-4 as they are on the other side of the chip. Pins 1-4 and pin 7 are all tied to ground by the traces on the PCB, so my guess is that the short was between pin 6 and pin 7 (which are right next to each other).