yamaha psr
 

anyone out there??

'Somebody' used a random 45v dc input when it should have been
12v.....guess what....now it wont work...The screen (orange) backlight
and (red) power l.e.d comes on...but thats all..
I've done the most basic thing by looking for an internal fuse,hoping
it could be that simple..
but cannot see any..
Can anyone please point me in the right direction?

yamaha psr
 

wrote in message
...
anyone out there??

'Somebody' used a random 45v dc input when it should have been
12v.....guess what....now it wont work...The screen (orange) backlight
and (red) power l.e.d comes on...but thats all..
I've done the most basic thing by looking for an internal fuse,hoping
it could be that simple..
but cannot see any..
Can anyone please point me in the right direction?


Very well could have blown all kinds of stuff. You'll need a service manual,
and if you aren't a tech type yourself, best just get it to a shop.

Mark Z.

yamaha psr
 

Given that the overvoltage was nearly four times the rated voltage, there's
a good chance virtually "everything" in the unit is blown. By all means have
a tech look at it, but I wouldn't be optimistic.

yamaha psr
 

William Sommerwerck wrote in message
. ..
Given that the overvoltage was nearly four times the rated voltage,
there's
a good chance virtually "everything" in the unit is blown. By all means
have
a tech look at it, but I wouldn't be optimistic.



And the fry factor by about the square , something approaching x16

--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/

yamaha psr
 

On Jan 23, 11:06*am, "Mark D. Zacharias"
wrote:
wrote in message

...

anyone out there??

'Somebody' used a random 45v dc input when it should have been
12v.....guess what....now it wont work...The screen (orange) backlight
and (red) power l.e.d comes on...but thats all..
I've done the most basic thing by looking for an internal fuse,hoping
it could be that simple..
but cannot see any..
Can anyone please point me in the right direction?

Very well could have blown all kinds of stuff. You'll need a service manual,
and if you aren't a tech type yourself, best just get it to a shop.

Mark Z.

If i knew exactly where to check,i hoped i could find precisely what
to replace-if its just a replaceable component that is..I have some
theory behind me from some electronics modules ive done, but havent
experience...thought if someone knew what and where to check
resistance/power/caps or whatever it could be straight forward but as
i said...ive no experience..
cant find a tech to look at it thats why gotta try sort it out
myself...
bummer...doesnt look hopeful does it..im looking for a service manual
at the moment-might shed some light on the situation...kepp lookin...
thanks M

yamaha psr
 

On Jan 23, 12:39*pm, "William Sommerwerck"
wrote:
Given that the overvoltage was nearly four times the rated voltage, there's
a good chance virtually "everything" in the unit is blown. By all means have
a tech look at it, but I wouldn't be optimistic.

unfortunately I cant find a tech to have a look...im in the process of
finding a service manual to hopefully troubleshoot and come across a
protection unit or something like that..but "virtually everything"
doesnt sound enticing!..
only got the thing at christmas,2nd hand with no dc input...should
have checked before i plugged in that 45v mother..
gonna keep on lookin-

thanks for your time Will
S

yamaha psr
 

The OP's problem implicitly raises an interesting point.

We don't think of IC circuitry (as opposed to discrete) as drawing a lot of
current. Nor do we think of it as being able to pull enough overcurrent for
a long-enough period -- without being damaged -- to pop a fuse.

Most electronic equipment has a fuse on the line side of the power supply,
and some has fuses on parts of the circuit that draw or pass a lot of
current (eg, an output stage). But I don't remember seeing fuses directly
protecting circuitry that's mostly LSI (or even SSI).

How often are fuses used in such circuitry?

yamaha psr
 

William Sommerwerck wrote in message
. ..
The OP's problem implicitly raises an interesting point.

We don't think of IC circuitry (as opposed to discrete) as drawing a lot
of
current. Nor do we think of it as being able to pull enough overcurrent
for
a long-enough period -- without being damaged -- to pop a fuse.

Most electronic equipment has a fuse on the line side of the power supply,
and some has fuses on parts of the circuit that draw or pass a lot of
current (eg, an output stage). But I don't remember seeing fuses directly
protecting circuitry that's mostly LSI (or even SSI).

How often are fuses used in such circuitry?



How many nS/uS to knock out silicon before the mS to knock out fuse wire ?
The fuse is just to give a bit of protection of reduced chance of
consequential combustion.


--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/