Larry,On my last post I meant 577 NOT 177.Tks to Jim for picking that mistake up.......... Don of HARTS-TVCR-ASC 9 Robert St,Oromocto,NB,Canada,E2V3N2 Tel-506-357-9785,Fax-506-357-6010 hartstv@xxxxxxxxxxx ----- Original Message ----- From: "Larry E." <videotech@xxxxxxxxxxxx> To: <techassist@xxxxxxxxxxxxx> Sent: Friday, July 25, 2003 2:49 PM Subject: [TechAssist] Re: RCA-CTC169AM,chass-f31221wn-32'' > Don, if the original C4104 was 15uf @ 50v I would replace it with that value > Pin 3 is correct so that`s not the problem. You mentioned in another > post that you replaced CR4118 with a NTE177, that`s not a good > substitute, has to be an ECG/NTE 580, the C voltage on Q4601 > appears to be a problem, it should be a steady 13.1 volts in standby > did you check replace C4118 off pin 16 of U4101 yet? What > happens to the voltages in the switchmode if you connect the collector > of the HOT but don`t turn the set on? Larry > Larry Eastman > American TV & Electronics > Crystal River, Fl. 34428 > 352-795-0124 > > hartstv@xxxxxxxxxxx wrote: > > > Tks for your reply,Larry.Here are the values of the orginal caps removed > > from the smps; > > C4102=2.2ufd/100v > > C4104=15ufd/50v > > C4108=47ufd/50v > > The voltage at Q4101 is varying from 159vdc to 164vdc. > > The voltage on the collector pad of the HOT Q4401 is varying from 13vdc to > > 40vdc;NOTE this is without the collector of HOT connected to pad & yes I'm > > using the correct grounds. > > Pin 3 of U4101 is varying from 0vdc to .013vdc. > > I know there are hot & cold grounds for these measurements.The HOT collector > > voltage is low because the chopper is not in it's proper duty cycle.This is > > the same voltage measured at the cathode of CR4116,the 145vdc source. > > I did replace C4104 with a 4.7/100v cap,as per your email but have same > > voltage readings.What I don't understand is the orginal cap was > > 15ufd/50v.Man this is wierd?? Tks again for your help...regards... > > Don of HARTS-TVCR-ASC > > 9 Robert St,Oromocto,NB,Canada,E2V3N2 > > Tel-506-357-9785,Fax-506-357-6010 > > hartstv@xxxxxxxxxxx > > > > ----- Original Message ----- > > From: "Larry E." <videotech@xxxxxxxxxxxx> > > To: <techassist@xxxxxxxxxxxxx> > > Sent: Thursday, July 24, 2003 8:56 PM > > Subject: [TechAssist] Re: RCA-CTC169AM,chass-f31221wn-32'' > > > > > Hi Don, you need to be carefull changing parts in a 169 chassis with a pa= > > > rts list from a 27" proscan, there are 4 different families of 169 chassi= > > > s`s and some of the parts > > > are very different, for example C4108 in your set (family 1) is supposed = > > > to be a > > > 47uf @ 50 volts but in a family 4 169 it`s a 39uf @ 100v, BIG difference= > > > =2E > > > The usual cause of pin 16 on U4101 fluctuating up and down is the 3 caps = > > > you changed, or U4101 is bad check the values, C4102=3D 2.2 @ 100v C410= > > > 4=3D 4.7 @ 100v(not 47uf) C4108=3D 47uf @ 50v. If those are good then th= > > > e set is either in ovp or ocp You should have the following in standby (s= > > > et plugged in but not turned on), Raw B+ on C of Q4101 =3D approx. 165 vo= > > > lts, Regulated B+ on C of HOT=3D approx.144 volts, 5v standby on E of Q46= > > > 01. If the above are correct, check voltage on pin 3 of U4101, it shouldn= > > > `t be above .6v (point 6 volts) if it is the > > > set is going into ocp shutdown. Let me know the results of these measurem= > > > ents, > > > I don`t have a scanner but I do have the schematics and 169 troubleshooti= > > > ng guide. > > > Remember that a lot of the capacitor values are different for the various= > > > 169 models > > > so be careful to replace what you pull out with the same value, Larry E > > > Larry Eastman > > > American TV & Electronics > > > Crystal River, Fl. 34428 > > > 352-795-0124 > > > pulling out > > > hartstv@xxxxxxxxxxx wrote: > > > > > > > This direct view 32'' unit has me baffeled.Orginally came in with the H= > > > OT shorted.Replaced with an OEM 2SD1885.Everything else was ok so fired i= > > > t up.The HV was 38.5KV,too hi,so took the chass out to bench test.Turned = > > > it on without a yoke plugged in & I think that's when my problems started= > > > =2EQ4802 smoked in the pin cct.Replaced it & plugged a yoke to the set.No= > > > w my smps won't start.Pin 16 reads 8.5vdc then slowly goes up to 10.5vdc = > > > & then starts going back down to 8.5v.So changed all the normal parts for= > > > this smps,ie,the U4101,C4102,4,8,Q4101.Did not help.Replaced the infamou= > > > s CR4118.Checked or replaced both LM311 in the vert & pin cct;also C4403,= > > > CR4401,CR4402.Again no go.Checked or replaced all trans in the PWM cct,Q4= > > > 405,6,7,8,9.Same results;the regulator is trying to start but keeps going= > > > up/down from 8.5v to 10.5v.Raw B+ is solid at 165vdc,no ripple.All these= > > > tests were done with HOT collector lifted.I have checked all my tips for= > > > this unit,& I know there's a ton of them but > > > > can't find the problem.I have changed so many parts too numereous to = > > > mention,ie caps,diodes,transistors but I'm stumped.Any assistance would b= > > > e greatly appreciated or if someone would be so kind to email a pdf for t= > > > his brute.The only print I have is a profax for the 27'' set.BTY i also c= > > > hecked all transistors in the Q4300 & Q4700 series.........TIA...........= > > > =2E > > > > Don of HARTS-TVCR-ASC > > > > 9 Robert St,Oromocto,NB,Canada,E2V3N2 > > > > Tel-506-357-9785,Fax-506-357-6010 > > > > hartstv@xxxxxxxxxxx > > > > > > > > ***********************************************************************= > > > ****** > > > > Classifieds! 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