Author: KermMartian
Posted: 17 Mar 2013 12:35:14 am (GMT -5)
That's a crystal oscillator, not a capacitor. ![Smile]()
I would imagine that's there so that the body of the oscillator doesn't short against the metal antistatic shield.
I believe R01H-R04H are key to this investigation. One of my TA3 TI-84+SE calculators has only R03H and R04H, as far as I can tell, both population by zero-ohm jumpers. Another TA3 TI-84+SE has all four pads; R03H and R04H are populated. I tried populating R01H, but the calculator appeared not to power on. Removing the jumper resolved the problem. Populating just R02H yielded the same results. Populating R01H and R02H together also yielded no boot. Tried another set of batteries, no boot. No USB activity, no I/O activity. Removing both jumpers did not appear to restore the device to functionality. However, it should be noted that this is very much a frankencalculator and subject to mood swings, hence my willingness to experiment on it in the first plce.
_________________
![]()
![]()
![]()
![]()
![]()
Posted: 17 Mar 2013 12:35:14 am (GMT -5)
| elfprince13 wrote: |
| There's an awful lot of red goop on what appears to be a relatively normal capacitor. Is it relatively high capacitance and they're worried about arcing on the board, or is there some more plausible explanation? If it's high enough capacitance that arcing would actually be a concern....what role is it playing? |
I would imagine that's there so that the body of the oscillator doesn't short against the metal antistatic shield.I believe R01H-R04H are key to this investigation. One of my TA3 TI-84+SE calculators has only R03H and R04H, as far as I can tell, both population by zero-ohm jumpers. Another TA3 TI-84+SE has all four pads; R03H and R04H are populated. I tried populating R01H, but the calculator appeared not to power on. Removing the jumper resolved the problem. Populating just R02H yielded the same results. Populating R01H and R02H together also yielded no boot. Tried another set of batteries, no boot. No USB activity, no I/O activity. Removing both jumpers did not appear to restore the device to functionality. However, it should be noted that this is very much a frankencalculator and subject to mood swings, hence my willingness to experiment on it in the first plce.
_________________
