[TechAssist] Re: Sony KV32XBR26 About Zener D1407 (8-719-110-90)
- From: "J Silverman" <greentron@xxxxxxxxxxxxxxxx>
- To: <techassist@xxxxxxxxxxxxx>
- Date: Wed, 15 Oct 2003 13:57:11 -0400
Avalanche diodes dont short from exceeding the breakdown voltage. They short
from the power that is dissipated from high reverse current melting the
rectifying junction, same as with the zener diode. If there is enough energy
available, the diode or zener will explode or fall apart after shorting.
Jerry Silverman
Greentron Inc
4 Newland Ave
Greenville SC 29609
864 232 3889
Fax 271 2080
mailto:greentron@xxxxxxx
----- Original Message -----
From: "Philip Bader" <tjanphyl@xxxxxxxxxxxxxxx>
To: <techassist@xxxxxxxxxxxxx>
Sent: Wednesday, October 15, 2003 11:02 AM
Subject: [TechAssist] Re: Sony KV32XBR26 About Zener D1407 (8-719-110-90)
> Most applications utilising cthe rowbar ckts above I've seen use an
> "avalanche diode" instead of a standard zener.Once the breakdown
> voltage is attained it shorts permanently.
> Phil Bader
>
> J Silverman wrote:
> >
> > If the zener is used for overvoltage protection the idea is for it to
short
> > quickly which causes the SMPS to shut down due to the SMPS protection
> > circuit. Normally, the overvoltage zener is not conducting or
dissipating
> > power. Use of higher wattage zeners could delay the shorting action
which
> > could might result in damage to components subjected to the overvoltage.
The
> > zener is considered a cheap, expendible "crowbar". In better made
equipment,
> > the overvoltage zener is just used to trigger an SCR. The SCR handles
the
> > short current until the power supply shuts down. In that kind of
equipment,
> > the zener and the SCR survive. I never gave it much thought, but
something
> > like that could easily be made, just requiring two leads, to tack into
power
> > supplies for troubleshooting, where overvoltage could cause damage to
> > sensitive components.
> > Jerry Silverman
> > Greentron Inc
> > 4 Newland Ave
> > Greenville SC 29609
> > 864 232 3889
> > Fax 271 2080
> > mailto:greentron@xxxxxxx
> > ----- Original Message -----
> > From: "Philip Bader" <tjanphyl@xxxxxxxxxxxxxxx>
> > To: <techassist@xxxxxxxxxxxxx>
> > Sent: Tuesday, October 14, 2003 2:15 PM
> > Subject: [TechAssist] Re: Sony KV32XBR26 About Zener D1407
(8-719-110-90)
> >
> > > Yes,tho not considered "proper". cathode-anode,cathode-anode.
> > > Remember to use oversized wattages, to compensate for voltage drops
> > > across the different voltage zeners.
> > > Such as, you need a 120 volt zener, and you series a 100 volt and a 20
> > > volt zener.Different current disappations for each.
> > > If you make the 120 volts zener with two 60 volt zeners, even voltage
> > > drop across them would occur.
> > > If half-watt is called for, I would use one watters.
> > >
> > > J Silverman wrote:
> > > >
> > > > You can string zener diodes in series to make up a specific voltage
when
> > you
> > > > need one quickly. One problem is if the zener is used as an
overvoltage
> > > > protector it will just blow up again if the overvoltage problem was
not
> > > > corrected.
> > > > Jerry Silverman
> > > > Greentron Inc
> > > > 4 Newland Ave
> > > > Greenville SC 29609
> > > > 864 232 3889
> > > > Fax 271 2080
> > > > mailto:greentron@xxxxxxx
> > > > ----- Original Message -----
> > > > From: "Neil Bowman" <tvdoctors@xxxxxxxxxxxxx>
> > > > To: <techassist@xxxxxxxxxxxxx>
> > > > Sent: Tuesday, October 14, 2003 12:08 AM
> > > > Subject: [TechAssist] Sony KV32XBR26 About Zener D1407
(8-719-110-90)
> > > >
> > > > > I've checked Tritronics and they don't have in stock. My local
> > supplier
> > > > here in Washington State didn't have it either but she crossed
> > 8-719-110-90
> > > > to NTE5037A and shipped it today. I checked the value after I hung
up
> > and
> > > > it's a listed as a 36 volt zener diode. Would this be satifactory.
> > This is
> > > > the craziest little diode that I have tried to find in stock.
Anyone
> > have
> > > > one to put in a envelope to send me, in case the NTE doesn't work
out?
> > > > Customer want's set fixed as quick as possible. Neil
> > > > >
> > > > > TV Doctors
> > > > > Monroe,Wa
> > > > >
> > > >
> >
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> > > --
> > > Philip Bader
> > > Jan Phyl TV Inc. (estab. 1976)
> > > 3420 Recker Hwy. Winter Haven, Fl. 33880
> > > Fax (863) 299-8821
> > > email: tjanphyl@xxxxxxxxxxxxxxx
> > > For Professional Technicians Only
> > >
> > >
> >
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> --
> Philip Bader
> Jan Phyl TV Inc. (estab. 1976)
> 3420 Recker Hwy. Winter Haven, Fl. 33880
> Fax (863) 299-8821
> email: tjanphyl@xxxxxxxxxxxxxxx
> For Professional Technicians Only
>
>
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