Every once in a while one of these comes up with a back panel singing
inductor that up-the-wall whines.

I tried everything reasonable involving damping the tuning fork like
shield, rubber mounts, etc.
Still could not get the noise acceptably low.

This is apparently a chronic problem that infects a significant number
of 2215's and probably 2213's as well.

Any cures or workarounds out there?

--
Many thanks,

Don Lancaster
Synergetics 3860 West First Street Box 809 Thatcher, AZ 85552
voice: (928)428-4073 email:

Please visit my GURU's LAIR web site at http://www.tinaja.com

AFAIK, there are no easy workarounds. As you probably are aware, Tek
came out with a retrofit kit that replaced the nasty triac prereg with
a TL594 based MOSFET prereg like in the later 2215A series. Actually,
the TL594 prereg is not that complex; I thought about building up a
small kit myself; but I would have to come up with one part that would
not be easy; the buck transformer. I have a couple of dead 2235's
around here; maybe someday I'll unwind one of those to see about
replicating them.

Jeff

On Mon, 16 Feb 2004 20:58:33 -0700, Don Lancaster
wrote:


Every once in a while one of these comes up with a back panel singing
inductor that up-the-wall whines.

I tried everything reasonable involving damping the tuning fork like
shield, rubber mounts, etc.
Still could not get the noise acceptably low.

This is apparently a chronic problem that infects a significant number
of 2215's and probably 2213's as well.

Any cures or workarounds out there?

Don Lancaster wrote in :


Every once in a while one of these comes up with a back panel singing
inductor that up-the-wall whines.

I tried everything reasonable involving damping the tuning fork like
shield, rubber mounts, etc.
Still could not get the noise acceptably low.

This is apparently a chronic problem that infects a significant number
of 2215's and probably 2213's as well.

Any cures or workarounds out there?


Welll,the original TEK cure(mod) was to clip out the original Triac pre-reg
circuitry and install a separate pre-reg PCB based on a TL494 IC.(also
referred to as OPT.48) I have one of these in my 2213.

TEK also tried a rubber cushion,but it didn't work.

Maybe installing a different inductor would work.

--
Jim Yanik
jyanik-at-kua.net

Jeff W wrote in
:

AFAIK, there are no easy workarounds. As you probably are aware, Tek
came out with a retrofit kit that replaced the nasty triac prereg with
a TL594 based MOSFET prereg like in the later 2215A series. Actually,
the TL594 prereg is not that complex; I thought about building up a
small kit myself; but I would have to come up with one part that would
not be easy; the buck transformer. I have a couple of dead 2235's
around here; maybe someday I'll unwind one of those to see about
replicating them.

Jeff

On Mon, 16 Feb 2004 20:58:33 -0700, Don Lancaster
wrote:


Every once in a while one of these comes up with a back panel singing
inductor that up-the-wall whines.

I tried everything reasonable involving damping the tuning fork like
shield, rubber mounts, etc.
Still could not get the noise acceptably low.

This is apparently a chronic problem that infects a significant number
of 2215's and probably 2213's as well.

Any cures or workarounds out there?



Or you could create a ordinary (60Hz)transformer based 43 volt DC supply to
replace the pre-reg.It would have to supply at least 1 amp at 43V,and would
only work for whatever primary voltage you selected for the XFMR,not the
90-250 VAC range of the Opt.48 pre-reg.

--
Jim Yanik
jyanik-at-kua.net

Jim Yanik writes:

Jeff W wrote in
:

AFAIK, there are no easy workarounds. As you probably are aware, Tek
came out with a retrofit kit that replaced the nasty triac prereg with
a TL594 based MOSFET prereg like in the later 2215A series. Actually,
the TL594 prereg is not that complex; I thought about building up a
small kit myself; but I would have to come up with one part that would
not be easy; the buck transformer. I have a couple of dead 2235's
around here; maybe someday I'll unwind one of those to see about
replicating them.

Jeff

On Mon, 16 Feb 2004 20:58:33 -0700, Don Lancaster
wrote:


Every once in a while one of these comes up with a back panel singing
inductor that up-the-wall whines.

I tried everything reasonable involving damping the tuning fork like
shield, rubber mounts, etc.
Still could not get the noise acceptably low.

This is apparently a chronic problem that infects a significant number
of 2215's and probably 2213's as well.

Any cures or workarounds out there?



Or you could create a ordinary (60Hz)transformer based 43 volt DC supply to
replace the pre-reg.It would have to supply at least 1 amp at 43V,and would
only work for whatever primary voltage you selected for the XFMR,not the
90-250 VAC range of the Opt.48 pre-reg.

Or maybe just a commercial AC-DC 48 V brick adjusted down to 43 V or
dropped to 43 V.

--- sam | Sci.Electronics.Repair FAQ Home Page: http://www.repairfaq.org/
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Important: The email address in this message header may no longer work. To
contact me, please use the feedback form on the S.E.R FAQ Web sites.

I read in sci.electronics.design that Jim Yanik wrote
(in ) about 'Tek 2215
question', on Tue, 17 Feb 2004:

Or you could create a ordinary (60Hz)transformer based 43 volt DC supply
to replace the pre-reg.It would have to supply at least 1 amp at 43V,and
would only work for whatever primary voltage you selected for the
XFMR,not the 90-250 VAC range of the Opt.48 pre-reg.

I have a small audio weighting filter, made by Dolby Laboratories, which
has a *linear* power supply covering 80 to 250 V without adjustment. It
has two small lamps in series with the transformer primary winding. But
that would be one crazy panel light if you did it with a 43 W output
linear supply!
--
Regards, John Woodgate, OOO - Own Opinions Only.
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

On a sunny day (Tue, 17 Feb 2004 15:28:22 +0000 (UTC)) it happened Jim Yanik
wrote in :

Or you could create a ordinary (60Hz)transformer based 43 volt DC supply to
replace the pre-reg.It would have to supply at least 1 amp at 43V,and would
only work for whatever primary voltage you selected for the XFMR,not the
90-250 VAC range of the Opt.48 pre-reg.
Its magnetic field might perhaps screw up the display.
Plastic spray worked on line output transformers in TV, not sure it is of
use here.

Every once in a while one of these comes up with a back panel singing
inductor that up-the-wall whines.
I tried everything reasonable involving damping the tuning fork like
shield, rubber mounts, etc.

Have you considered active noise mitigation - bolt a voice coil to it
and inject a 180-degree-out-of-phase signal to damp the vibration?

"Lewin A.R.W. Edwards" wrote:

Every once in a while one of these comes up with a back panel singing
inductor that up-the-wall whines.
I tried everything reasonable involving damping the tuning fork like
shield, rubber mounts, etc.

Have you considered active noise mitigation - bolt a voice coil to it
and inject a 180-degree-out-of-phase signal to damp the vibration?

It makes more sense to sell the unit to a deaf person.

--
Many thanks,

Don Lancaster
Synergetics 3860 West First Street Box 809 Thatcher, AZ 85552
voice: (928)428-4073 email:

Please visit my GURU's LAIR web site at http://www.tinaja.com