8/10/2019 DAOS COMUNES EN TV Zenith.doc

1/2

Zenith TV's From Mid 90's

From Apr. 2002 SpeakerPage 15

NOTE: See Letter to the Editor at the end of this article

The Compete ZenithBy: Joe Sopko

From an unidentified Technician on one of the "Other" repair forums is aposting that covers many of the Zenith TV's from the mid '!'s They #erepag!ed "# reg!ator $ai!res$ and The Tech ca%ims that if you check

these items you #i%% fi& aout !( of a%% )enith's

*e a%so %ists a method of iso%ating the +ine Fi%ament$ #hich #as the causeof the ,egu%ator fai%ure in the first p%ace -s our Technician popu%ationages$ and your memory fades$ you might #ant to ".%ip and Save" thisartic%e for #hen you say "/o#$ 0ust #hat 1-S that resistor in the

regu%ator2"

3 4.56763 8 ST,96!73 8 ;. ?6763 8 3>393>@79!3 or 9!> use ;.6 for >" sets and /T;37>A" sets fast s#itcher ;. 1att7 ,567>7 8 3!!+ C 3> 1att ,5676> 8 3=!+ C 3> 1att@ ,56766 8 3 Ohm C 3> 1attA ,56767 8 76 Ohms origina% sets use 3 1att Dater Eode%s use >

1att= ,5676 8 3! Ohms C 3 1att .676> 8 3!!>vdc change this on any set in for service causes a%%

kinds of pro%ems3!.6767 8 >>uf

33iodes .r6763 .r676> .r6766 check these #ith the ,egu%ator

and Transistor out of circuit easier3>%ther Pro"ems&

.567@ genera%%y 8 3!uf C either 63vdc or 6!vdc

.>>3> 8 >>3@vdc cause agc$ pu%%ing tearing$ sGuea%ing$ etc

4f the picture tue is shorted$ try tota%%y disconnecting and iso%ating thefi%ament po#er supp%y from the f%yack Take some #ire and out >96 #raps

around the iron core on the f%yack and use this for your fi%ament vo%tageEake sure to do a#ay #ith any coup%ing or fi%ter caps on .,T socket$ as

this has to e tota%%y iso%ated$ even if you have to cut or scrape a#ay someof the copper foi% This #i%% take care of a %ot of the "%ue screen"$ etc$

cathode to fi%ament shorts that continuous%y %o# the po#er supp%y Sureeats uying an iso%ation transformerH

8/10/2019 DAOS COMUNES EN TV Zenith.doc

2/2

"The Speaker" #ishes #e cou%d give proper credit to the author of thisartica%$ ut on other Tech Forums$ the memers use on%y /icknames for

their screen name 1e thank the "Eystery Tech" for this information$#hoever he may e

eo(&)etter To The *ditor Con+erning The Arti+e A"o,e

Detter From:*erman -ckerman

,eyno%ds TV I Video SvcSan iego .- >33@

4 en0oy reading your ne#s%etter and thanks for inc%uding me on your

mai%ing %ist Found a fe# pro%ems in the -pri% >!!> edition 4 thought 4'dring to your attention:

"The .omp%ete Zenith" y the "mystery Tech"*e states "iso%ating the +ine Fi%ament$ #hich #as the cause of the,egu%ator fai%ure in the first p%ace"

-%/Virtua%%y -DD regu%ator fai%ures in these units are caused y a