Hi,

PSU has tickling sound problem. I read that changing the regulator IC
will solve the problem. So I change the KA3842B Controller IC with
UC3842B IC (On Semiconductor). Tickling sound disappears but PSU could
not power on the Point of Sales terminal; just managed to flicker on
the terminal display only.

Should I use only the original KA3842B Controller IC?

Thanks for your advise.

Seventh Prince

"?B?U2V2ZW50aFByaW5jZeS4g+WwkeeItw==?=" wrote
in ups.com:

Hi,

PSU has tickling sound problem. I read that changing the regulator IC
will solve the problem. So I change the KA3842B Controller IC with
UC3842B IC (On Semiconductor). Tickling sound disappears but PSU could
not power on the Point of Sales terminal; just managed to flicker on
the terminal display only.

Should I use only the original KA3842B Controller IC?

Thanks for your advise.

Seventh Prince



It's probably bad electrolytic caps,where their ESR increased,a very common
failure of switcher power supplies.

--
Jim Yanik
jyanik
at
kua.net

On 10/13/05 7:11 PM, in article
, "SeventhPrinceÆßÉÙÒ¯"
wrote:

Hi,

PSU has tickling sound problem. I read that changing the regulator IC
will solve the problem. So I change the KA3842B Controller IC with
UC3842B IC (On Semiconductor). Tickling sound disappears but PSU could
not power on the Point of Sales terminal; just managed to flicker on
the terminal display only.

Should I use only the original KA3842B Controller IC?

Thanks for your advise.

Seventh Prince


PSU (Portland State University) reports they have many tickling sounds.
All the way from grunts, guffaws, and screeches, to high-pitched shrieks and
gasps.

Jim Yanik writes:

"?B?U2V2ZW50aFByaW5jZeS4g+WwkeeItw==?=" wrote
in ups.com:

Hi,

PSU has tickling sound problem. I read that changing the regulator IC
will solve the problem. So I change the KA3842B Controller IC with
UC3842B IC (On Semiconductor). Tickling sound disappears but PSU could
not power on the Point of Sales terminal; just managed to flicker on
the terminal display only.

Should I use only the original KA3842B Controller IC?

Thanks for your advise.

Seventh Prince



It's probably bad electrolytic caps,where their ESR increased,a very common
failure of switcher power supplies.

See the SMPS repair guide at the sites below.

--- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

Important: Anything sent to the email address in the message header above is
ignored unless my full name is included in the subject line. Or, you can
contact me via the Feedback Form in the FAQs.

That was almost funny.. :| probaly funnier if you associate psu with
portland state. not power supply like me.

"Don Bowey" wrote in message
...
On 10/13/05 7:11 PM, in article
, "SeventhPrinceÆßÉÙÒ¯"
wrote:

Hi,

PSU has tickling sound problem. I read that changing the regulator IC
will solve the problem. So I change the KA3842B Controller IC with
UC3842B IC (On Semiconductor). Tickling sound disappears but PSU could
not power on the Point of Sales terminal; just managed to flicker on
the terminal display only.

Should I use only the original KA3842B Controller IC?

Thanks for your advise.

Seventh Prince


PSU (Portland State University) reports they have many tickling sounds.
All the way from grunts, guffaws, and screeches, to high-pitched shrieks
and
gasps.

It's probably bad electrolytic caps,where their ESR increased,a very common
failure of switcher power supplies.

Sam, How do I recognise which caps are bad? Thanks

?B?5LiD5bCR54i3U2V2ZW50aCBQcmluY2U=?=
wrote in :


It's probably bad electrolytic caps,where their ESR increased,a very
common failure of switcher power supplies.

Sam, How do I recognise which caps are bad? Thanks


If you don't have an ESR meter like the Dick Smith Electronics meter(very
affordable,very good),then you're best bet is to replace all the
electrolytics.

Also look for discolored,swollen,or bulging electrolytic caps;indications
they are dissipating excessive heat.

--
Jim Yanik
jyanik
at
kua.net