I think a 2SD1881 should have a base-emitter resistance because it has a damper. (I always wondered if you can have a transistor with a damper but without base-emitter resisor). Note that a 2SD1882 and higher are in a different family without dampers. I once measured the base-emitter resistance of all the outputs I had in stock and found readings from 25 to 70 ohms. I also found a 2 to 1 ratio of the resistances of the same transistor type but from different batches (or between "generic" and original) Does anyone know if this resistance make a difference in how hot the transistor will operate? I do not have a D1881 in stock but I just went thru a bag of D1880 and found resistances from 32 ohms to 47 ohms with most of them at 40 ohms. John. Tri-County Tv wrote: > Jim, > I used a 2sd1881 and measured it before I installed it and it did not > show any resistance from base to emitter. It was my last one and the TV is > gone now, should a 2sd1881 have resistance from base to emitter? I know what > you are referring to as I also have seen many HOT that have about 50 ohms > from base to emitter. And at first I thought the original was ok , until I > checked it against my 2sd1881 which did not show any resistance. > Tom Berger > Tri-County TV > Robbinsville > North Carolina 28771 > (tricountytv@xxxxxxxxxxxxx) > ----- Original Message ----- > From: "Jim Myers" <jr.myers@xxxxxxxxxxx> > To: <techassist@xxxxxxxxxxxxx> > Sent: Wednesday, July 16, 2003 1:36 PM > Subject: [TechAssist] Re: Zenith flyback --FIXED > > > >>Tom, R-U sure? Most HO transistors have an internal base to emitter > > resistor > >>of about 45 ohms. This is a mistake we have all made at least once. >>************************************************** >>Jim Myers >>Since 1972 >>Telrad Electronic Services Co. >>Fort Wayne, IN 46815 >>************************************************* >>----- Original Message ----- >>From: "Tri-County Tv" <tricountytv@xxxxxxxxxxxxx> >>To: <techassist@xxxxxxxxxxxxx> >>Sent: Wednesday, July 16, 2003 12:29 PM >>Subject: [TechAssist] Re: Zenith flyback --FIXED >> >> >>Jeff, >> Sorry it took a little while to get back to you, as I busy kicking >>myself in the AXX as you were completely right, and I should have known >>better. The H.O. Transistor has a base to emitter short of 45 ohms, when I >>checked it in circuit it read shorted but I took for granted it was just >>drive transformer secondary winding. But when you think about it > > logically, > >>it had to be the H.O.Transistor. Thanks Again , and to all who replied so >>quickly. >>Tom Berger >>Tri-County TV >>Robbinsville >>North Carolina 28771 >>(tricountytv@xxxxxxxxxxxxx) >>----- Original Message ----- >>From: "Shoreline Electronics" <jstielau@xxxxxxxx> >>To: <techassist@xxxxxxxxxxxxx> >>Sent: Wednesday, July 16, 2003 12:23 PM >>Subject: [TechAssist] Re: Zenith flyback --need sub info >> >> >> >>>Remove the output transistor completely: Fire up the set and check for >> >>good >> >>>base drive...that will confirm your H-drive question: >>> >>>Try another output transistor to be sure....it really sounds like it's >>>defective...since PS is not squealing once you unsolder the collector. >>> >>>========================== >>>Jeff Stielau >>>Shoreline Electronics Repair >>>344 East Main Street >>>Clinton,CT 06413 >>>860-399-1861 >>>860-664-3535 (fax) >>>jstielau@xxxxxxxx >>>========================== >>>"If you push something hard enough it will fall over." >>>Fudd's First Law of Opposition - Sir Sidney Fudd >>> >>> >>>----- Original Message ----- >>>From: "Tri-County Tv" <tricountytv@xxxxxxxxxxxxx> >>>To: <techassist@xxxxxxxxxxxxx> >>>Sent: Wednesday, July 16, 2003 12:14 PM >>>Subject: [TechAssist] Re: Zenith flyback --need sub info >>> >>> >>> >>>>Jeff, >>>> I checked that and it's good.I did notice that there is no b+ >>> >>>getting >>> >>>>to the driver transformer and I'm not sure if I should have voltage >>> >>there >> >>>>when you first plug it in. >>>>Tom Berger >>>>Tri-County TV >>>>Robbinsville >>>>North Carolina 28771 >>>>(tricountytv@xxxxxxxxxxxxx) >>>>----- Original Message ----- >>>>From: "Shoreline Electronics" <jstielau@xxxxxxxx> >>>>To: <techassist@xxxxxxxxxxxxx> >>>>Sent: Wednesday, July 16, 2003 12:02 PM >>>>Subject: [TechAssist] Re: Zenith flyback --need sub info >>>> >>>> >>>> >>>>>Your Horizontal Output is probably shorted. >>>>> >>>>>========================== >>>>>Jeff Stielau >>>>>Shoreline Electronics Repair >>>>>344 East Main Street >>>>>Clinton,CT 06413 >>>>>860-399-1861 >>>>>860-664-3535 (fax) >>>>>jstielau@xxxxxxxx >>>>>========================== >>>>>"If you push something hard enough it will fall over." >>>>>Fudd's First Law of Opposition - Sir Sidney Fudd >>>>> >>>>> >>>>>----- Original Message ----- >>>>>From: "Tri-County Tv" <tricountytv@xxxxxxxxxxxxx> >>>>>To: <techassist@xxxxxxxxxxxxx> >>>>>Sent: Wednesday, July 16, 2003 11:19 AM >>>>>Subject: [TechAssist] Zenith flyback --need sub info >>>>> >>>>> >>>>> >>>>>>Hello, >>>>>> I got this zenith color TV model SS2761S , module 9-913 >>>>> >>,and >> >>>>the >>>> >>>>>flyback had a slit in the side with stuff oozzing out , Flyback # >>>> >>>95-4203 >>> >>>>, >>>> >>>>>when you look this # up on tritronics, it shows a 95-4203-REP for 17 >>>>>dollars, so I ordered it, and installed it into the module and now , >>>> >>>when >>> >>>>>you plug it in, the ps squeals, so I replaced all the usual ps >>>> >>>components, >>> >>>>>and same problem,also checked for shorts on secondary of fly and >>>> >>>>everything >>>> >>>>>looks ok, If I disconnect the collector of the HOT it stops >>>> > squealing > >>>and >>> >>>>ps >>>> >>>>>voltages return to normal, however I am not reading and B+ on any >>>> > legs > >>>of >>> >>>>>the driver transformer, I do not have the schematic and would >>>> > greatly > >>>>>appreciate if someone could upload one. Could this replacement fly >>>> > be > >>>the >>> >>>>>trouble? Has anyone had experience with this flyback? >>>>> >>>>>>Tom Berger >>>>>>Tri-County TV >>>>>>Robbinsville >>>>>>North Carolina 28771 >>>>>>(tricountytv@xxxxxxxxxxxxx) >>>>>> >>>>> > **************************************************************************** > >>>>>* >>>>> >>>>>>CHECK OUT THE NEW CHATROOM! Just login and click on chat! >>>>>>http://www.tech-assist.org/secure/tip/main.htm >>>>>>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/ >>>>>> >>>>> >>>>> > **************************************************************************** > >>>>* >>>> >>>>>CHECK OUT THE NEW CHATROOM! 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