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 > > > > > **************************************************************************** > > * > > > Classifieds! Buy or Sell! > > > http://sell.tech-assist.org > > > The Tech Address Book: > > > http://www.tech-assist.org/secure/tip/contact.htm > > > Add a Repair Tip Here, or Change/Remove your Email Address: > > > http://www.tech-assist.org/secure/tip/main.htm > > > Lost Password: > > > http://www.tech-assist.org and select "Lost your Login Info?". > > > Email Archives: > > > //www.freelists.org/archives/techassist/ > > > > **************************************************************************** * > > Classifieds! Buy or Sell! > > http://sell.tech-assist.org > > The Tech Address Book: > > http://www.tech-assist.org/secure/tip/contact.htm > > Add a Repair Tip Here, or Change/Remove your Email Address: > > http://www.tech-assist.org/secure/tip/main.htm > > Lost Password: > > http://www.tech-assist.org and select "Lost your Login Info?". > > Email Archives: > > //www.freelists.org/archives/techassist/ > > -- > 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 > > **************************************************************************** * > Classifieds! Buy or Sell! > http://sell.tech-assist.org > The Tech Address Book: > http://www.tech-assist.org/secure/tip/contact.htm > Add a Repair Tip Here, or Change/Remove your Email Address: > http://www.tech-assist.org/secure/tip/main.htm > Lost Password: > http://www.tech-assist.org and select "Lost your Login Info?". > Email Archives: > //www.freelists.org/archives/techassist/ ***************************************************************************** Classifieds! Buy or Sell! http://sell.tech-assist.org The Tech Address Book: http://www.tech-assist.org/secure/tip/contact.htm Add a Repair Tip Here, or Change/Remove your Email Address: http://www.tech-assist.org/secure/tip/main.htm Lost Password: http://www.tech-assist.org and select "Lost your Login Info?". Email Archives: //www.freelists.org/archives/techassist/