shotguntech
1 Copper

Studio 1749 will not power up

All of a sudden just died. Charger "blue band" is on. Voltage at end of charging cable +19V (unloaded - no laptop connected). Will not power-up using charger (with or without battery pack installed).

Battery state just above laptop charger plug-in port always "off" - (never amber or white).

Red power button on laptop will not light / flash - just appears dead.

Tried coin battery (original 10 years old) voltage was 3v - low but not a game changer. New coin battery about 3.15v - no change.

Buzzed charger common direct from laptop charging port to battery plug-in contact. Found no direct connection between +19 (center pin) on laptop charger port to battery plug-in contact. Should there be one ? I suspect no because it probably has to go thru a bunch of (not so) happy HS before it gets to the battery.

Suggestions ?

Thanks - Bruce

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3 Replies
8 Xenon

RE: Studio 1749 will not power up

The center pin makes contact with an adapter-detect logic circuit that enables the battery charging.  Even if that pin is missing, the system will power up unless something else is wrong - the battery won't charge without the pin making contact, though.

Try powering up with no battery (AC only) -- if it still won't, replace the DC jack first:

<<www.parts-people.com/index.php?action=item&id=6791>>

If that doesn't solve the power up problem, replace the mainboard.

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shotguntech
1 Copper

RE: Studio 1749 will not power up

Already tried power with A/C adapter only (no battery installed) - "no soap".

Interesting though - there are 3 contacts on A/C adapter (outer ring / inner ring / and center pin). I measure 19.5vdc between the outer and inner rings (charger voltage I suspect) - Center pin on charger measures about 180mv - so question is now - does the charger "signal" the laptop to it's presence in which case I would expect to see at least something >1vdc on the charger center pin. Is the laptop "listening" for the charger (I which case I would expect the charger center pin to be at GND "enable").

In other words "who tells who"

Thanks - Bruce - BTW - Thanks for the quick response

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8 Xenon

RE: Studio 1749 will not power up

The center pin enables the charge circuit -- not the power circuit to the system.  The adapter is OK at least as far as powering the system is concerned, meaning the fault is either with the DC jack or the power circuit on the mainboard.

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