rca ctc1698f


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kingm316
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Apr 19, 2010, 12:25 PM

Post #1 of 115 (7858 views)
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rca ctc1698f	Can't Post

i have an rca tv of model g35302wk and it won't turn on. when i push power on tv or the remote nothing happens no sounds either. i believe the problem is in the regulator. i have 160v dc on the c7 so i have b+ raw but i do not have any standby voltages. pin 15 and 16 of u4101 are only 2.5v each and they should be 11v and 8v right? the 33k resistor has been checked good and i have replaced it, just to be sure it is good, and it is still 2.5 right after the resistor. i believe that u4101 is bad is there something else to check to be sure before before i do? thanks for any help

Ron.M
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Apr 19, 2010, 8:52 PM

Post #2 of 115 (7845 views)
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Re: [kingm316] rca ctc1698f [In reply to]	Can't Post

kingm316;....

The 1st thing I'd like you to check is the H.O.T. ...
That's the Horiz Out Transistor Q4401 for a short from collector to chassis ground....
IF that is shorted , remove it......
Next go to the Chopper Transistor , Q4101 collector to HOT (AC) chassis ground....
IF that one is shorted , you are going to have fun....
If not , GOOOOOD !!!!.....
You have 3 caps to check....
#1= C4108 , 47 mfd....(35 vdc ??)
#2= C4104 , 15 mfd....(Forgot vdc , maybe a 35 vdc)
#3= C4102 , 2.2 mfd ...100 vdc

Use a GOOD ESR meter & value meter to check those caps....
C4108 straddles a 3.0 v zenner near Q4101....
Be SURE you get the cap polarity correct on ALL the caps , especially C4108.....
If C4108 is bad replace with a 50 mfd at 50 vdc....
If C4104 is bad replace with a 15 mfd at 50 vdc...Do NOT sub !!!..
If C4102 is bad replace with a 2.2 mfd at 100 vdc...Do NOT sub !!!.

IF either Q4401 OR Q4101 check shorted , you could have a serious problem on your hands.....
SO , my suggestion would be to replace the IC (It's 99.96% bad) & ALL 3 caps IF Q4101 is NOT shorted....
The last time I checked , Q4101 was expensive & U4101 was pretty cheap..... Unsure

....
Your call.....
I don't know if you have a manual or not...
BUT , I have a pix of the power supply below from one of my generic service manuals....
There are some differences in the voltages & some values (For example C4108 is shown as
39 mfd , the ORIGINAL value when most CTC169 chassis were made..), but it is very useful....

EDIT:....
After a 2nd cup of coffee & taking another look at my schematic above , I realized that Q4101 HAS to be GOOD since you have 160 vdc on C7 (C4107)....
SORRY about that........

This should get you started....
If you need more , just post.....

GOOD LUCK & have fun....

Later...Ron.M.... Cool

.....
Veteran & Retired TV technician

(This post was edited by Ron.M on May 7, 2010, 4:37 PM)

kingm316
User

Apr 20, 2010, 2:27 AM

Post #3 of 115 (7832 views)
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Re: [Ron.M] rca ctc1698f [In reply to]	Can't Post

thanks for the start ron so i changed the u4101 and the three capacitors with ones of of another ctc169 board i got from a tv repair guy. both the horizontal and chopper transistor checked ok from how you said to check. plugged it in and now i still have 160v on c7 and pin 15 and 16 of u4101 are now about 8 or 9v instead of 2.5 like it used to be. is there anything else i should check or were i should see if i have voltage at. thanks again.

Ron.M
Veteran

Apr 20, 2010, 5:41 PM

Post #4 of 115 (7823 views)
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Re: [kingm316] rca ctc169 [In reply to]	Can't Post

kingm316;....

Yup , we have more to check....

Now you have the primary side apparently working , we'll move on to the secondary voltage checks....
(I would normally ask to check the negative voltage at the base of Q4101 Chopper , but that's a bit risky given your unknown Electronic/TV Repair experience..)
In the following diagram below , the pin numbers on T4102 may not be the same as yours...
But for reference purposes I'll use the ones on the diagram for you to see where to go on your board...
Off pin #9 there should be about 130/140 vdc with the set OFF !!!!...
IF you can't find it there , go to the collector of Q4401 (Horiz Out Trans.) & read it there....
Off pin #3 there should be about 12/15 vdc coming off CR4118....
IF those 2 voltages are OK , then it should be OK to try to turn the TV on....

A bit of friendly advice.....
Those 3 caps you replaced are known for causing numerous problems (Some serious..)
in the CTC169 chassis....
The ones you got off the used board are most likely at OR near their
range of giving you trouble.....
They are CHEAP to buy & replace with NEW.!!!!
PLEASE do NOT trust those used caps....

Let me/us know how this works out for you...
THANKS.....

GOOD LUCK....

Later...Ron.M..... Cool

....
Veteran & Retired TV technician

kingm316
User

Apr 21, 2010, 3:03 AM

Post #5 of 115 (7812 views)
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Re: [Ron.M] rca ctc169 [In reply to]	Can't Post

i have never really worked on tvs but i do know the basics of electronics pretty good. i have checked the voltage at pin 9 and 7 and 3 and 4 of the chopper transformer and used the coaxial,rca jacks or the heatsink for the HOT for ground and have zero volts. but i measured the collector and it had 160v. i traced it back and found 160 at pin 11 of the flyback then from pin 1 and it stops at cr116.also c141 has 160, all those measurements are on the coaxial and rca ground. but i noticed the schematic you have is alittle different than my board because c140 and cr116 are both on pin 9. and pin 7 just goes to a ground. i will try to get new caps tomorrow but my local radioshack has very little selection any more, but if you know of an online store i would appriciate it because for some reason i can not find one that really helps me. thanks again for your help.

Ron.M
Veteran

Apr 21, 2010, 6:50 PM

Post #6 of 115 (7803 views)
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Re: [kingm316] rca ctc169 [In reply to]	Can't Post

kingm316;....

OK....Now we have to do this;=>...
""I would normally ask to check the negative voltage at the base of Q4101 Chopper , but that's a bit risky."""
I must caution you to use care when you do this because all it takes is one second to blow the transistor & the 1.8 ohm , 15 watt fusistor (R1)...
Hook up your DVM from the base of Q4101 (Chopper) to Hot Ground...
Hot ground should be the metal strip/flange(?) that Q4101 is mounted on...
It will be live if you have the chassis plugged in....
You should get a reading of NO less than -1.5 vdc....(Negative -)...

Let me/us know what you get....OK....THANKs.... Wink

....

Later...Ron.M.... Cool

....
Veteran & Retired TV technician

kingm316
User

Apr 22, 2010, 1:19 AM

Post #7 of 115 (7792 views)
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Re: [Ron.M] rca ctc169 [In reply to]	Can't Post

i checked for voltage at the base of Q4101 and have zero. i guess the u4101 i used is bad is what i am starting to think. also i was wondering if i should be getting 160v at the collector of the HOT but not at the chopper, is that normal or is there another problem or is it all connected. if u4101 is bad do you know of a place were i can get a new one.

Ron.M
Veteran

Apr 22, 2010, 3:59 AM

Post #8 of 115 (7788 views)
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Re: [kingm316] rca ctc169 [In reply to]	Can't Post

kingm316;....

I think you got it....U4101 more than likely bad.....
Did you check those 3 caps I asked you to ???
Not only the originals BUT the ones you used to replace them with ????
You should be getting 160 vdc at the collector of Q4101 ONLY !!!...
The heat sink that Q4101 (Chopper) is mounted on is also Hot ground....
So connect your negative lead to it & the positive lead
to the collector & you should read 160 vdc there....
IF you are reading 160 vdc at the collector of the HOT (Horiz Out Transistor=Q4401) ,
then you are not hooking up your test leads correctly OR you are reading at a wrong location !!!...
Q4401 will have ~140 vdc when U4101 & it's circuit are working properly....
As for the IC;...Look on the top of the IC for a TDA or TEA number....
IF memory serves , I think it's a TEA2261....

http://www.bdent.com/....jsp?partnum=TEA2261

Sells for $4.79 +s&h...

http://www.acme-sales.net/...USA&p_id=TEA2261

Sells for $3.49 + s&h

Memory served !!!! ...Here's what's at this website;=>....
TEA2261
ST integrated circuit
RCA # 200419
(U4101V on CTC169 chassis)

If you search this website ^^^ carefully , you'll find all the caps you need for this repair....

""If C4104 is bad replace with a 15 mfd at 50 vdc<<They have it at 63 vdc ...OK to use..."""
""If C4108 is bad replace with a 50 mfd at 50 vdc....<<They have a 47 mfd at 50 vdc,,,OK to use."""
""If C4102 is bad replace with a 2.2 mfd at 100 vdc..<<They have it at 2.2 mfd at 100 vdc...excact..Ok to use..."""
Click on capacitors on the left side....When you do that a list of assorted styles opens up...Click on Radial Electrolytics...Then go to the volts , scroll down till you find each cap...

http://www.mcmelectronics.com/product/TEA2261

Sells for $5.40 + s&h

Order at your own risk....The only one I'm familiar with is
MCM , but they do NOT have ALL the parts you need...

GOOD LUCK..... Laugh

....

Let me/us know what you find & decide to do ...OK...THANKS....

Later...Ron.M.... Cool

....
Veteran & Retired TV technician

(This post was edited by Ron.M on May 7, 2010, 4:27 PM)

kingm316
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Apr 22, 2010, 1:24 PM

Post #9 of 115 (7785 views)
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Re: [Ron.M] rca ctc169 [In reply to]	Can't Post

thanks for all those sites i haven't come across any of them before. no i havn't been able to test the caps because my meter doesn't have the function to test them but i will replace them when i get them. but with the collector of the HOT i am measuring it with the positive lead on the collector of the transistor and the negative lead on its heatsink or the ground on the coaxial cable or the outside of the rca jacks and i do get 160v. but i am sure i am measuring the right spot because i have been messing with this tv for awhile and i also removed the HOT from the extra board i have. so i guess it is backfeeding from somewhere else but i will leave it alone until i get the new parts so i can see if they will clear it up. i really appriciate all this help your giving me because it would be great to get this thing out of the middle of my room since it has been there for about a year i think.

Ron.M
Veteran

Apr 22, 2010, 4:56 PM

Post #10 of 115 (7779 views)
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Re: [kingm316] rca ctc169 [In reply to]	Can't Post

kingm316;.....
BEFORE you go & order anything , lets find out what is going on here....
With the set unplugged , discharge the 160 vdc to BOTH grounds...
That is , connect a jumper from where you get the 160 vdc to Hot & cold chassis grounds....
You WILL get a spark.....
Make SURE it IS discharged....
When you read 0 vdc , connect one lead from your meter to the collector of Q4401 & the other to Q4101....
Set your meter to read ohms....
Post back with your reading....

You said;=>...""" so i guess it is backfeeding from somewhere else but i will leave it alone"""
NO , we are NOT going to leave it alone.....It IS a problem that we MUST find the reason for....

""" but with the collector of the HOT i am measuring it with the positive lead on the collector of the transistor and the negative lead on its heatsink or the ground on the coaxial cable or the outside of the rca jacks and i do get 160v."""

WHICH "Q" are you reading the 160 vdc on ???...

Later...Ron.M.... Cool

.....
Veteran & Retired TV technician

(This post was edited by Ron.M on Apr 22, 2010, 10:55 PM)

kingm316
User

Apr 23, 2010, 2:48 AM

Post #11 of 115 (7763 views)
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Re: [Ron.M] rca ctc169 [In reply to]	Can't Post

i measured the resistance of the q4401 collector and q4101 collector and got 7M ohms and then went down to 6.2M ohms. i then rechecked the volts again and to clarify a little better q4401 collector to cold ground is 158v, and to hot ground is 174v. and q4101 to hot ground is 160v, and to cold ground is 60v. i hope this helps clarify things if not just tell me which reading would help. i hope you can make sense of it thanks.

jaysonsmith35
New User

Apr 23, 2010, 9:19 AM

Post #12 of 115 (7761 views)
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Re: [Ron.M] rca ctc1698f [In reply to]	Can't Post

hi

make money from home

jts1957
Veteran

Apr 23, 2010, 6:25 PM

Post #13 of 115 (7751 views)
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Re: [jaysonsmith35] rca ctc1698f [In reply to]	Can't Post

How high are you?

-------------------------
Location: Far, Far Away

Ron.M
Veteran

Apr 23, 2010, 7:51 PM

Post #14 of 115 (7742 views)
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Re: [kingm316] rca ctc169 [In reply to]	Can't Post

jts1957;......

From "jaysonsmith35";=>...
""""hi'''''
From you;=>...
""How high are you?"....
From me;=>...
He's got a screw loose at least....
He joined today & makes his stupidity abundantly apparent by making his 2 letter post !!!!...
Your cat could have done a better job.....
Later.....

kingm316;.....

OK....Now it makes sense to me.....ALL is well.....
Sort of......

Lets see what happens when you get the parts in & installed....
When you do , read & repeat the following voltages;=>...
Off pin #9 (or C4141) there should be about +130/140 vdc with the set OFF !!!!...
IF you can't find it there , go to the collector of Q4401 (Horiz Out Trans.) & read it there....
Off pin #3 (or C4145) there should be about +12/15 vdc coming off CR4118....
Off pin #4 (or C4143) there should be about +7 vdc comimg off CR4117...
This time do NOT turn the set on....
Post readings....
I will then advise what your next step will be....OK...THANKS....

FYI:=>....
On the new IC there will be a "dot" in one of the corners on the top side of the IC....
That is Pin #1....Make sure it goes into Pin #1 on the board....
IF you install it backwards , you risk blowing the IC....Just a heads up.... Wink

....

Later...Ron.M.... Cool

....
Veteran & Retired TV technician

(This post was edited by Ron.M on Apr 23, 2010, 8:02 PM)

jts1957
Veteran

Apr 24, 2010, 1:08 AM

Post #15 of 115 (7735 views)
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Re: [Ron.M] rca ctc169 [In reply to]	Can't Post

Inky does all my typing - he spells better. Wink

[kingm316]...

Reference COLD (Tuner) ground for the voltages Ron just mentioned. Cool

-------------------------
Location: Far, Far Away

kingm316
User

Apr 30, 2010, 3:15 AM

Post #16 of 115 (7699 views)
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Re: [jts1957] rca ctc169 [In reply to]	Can't Post

while i have been waiting for parts i rechecked some voltages and messed up and made a spark.oops. and that blew r1 a 1.8 ohm 15w resistor. so i went to the tv guy i got the extra board from and got another one from him but it is 2.7 ohm 15w, he says it will work. then i got the new u4101 and installed it along with the 3 new caps, which all came in a kit from acme. before i plugged it in i checked q4101 again and it has all three legs shorted together, so it was also blown when i messed up. i removed q4101 and am wondering if there are any voltages i can check with q4101 removed until i get a new one. i have not plugged in the tv yet because i don't know if not having q4101 installed will hurt it anything. also if there is anything i should check because i blew the r1.

Ron.M
Veteran

Apr 30, 2010, 6:00 PM

Post #17 of 115 (7683 views)
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Re: [kingm316] rca ctc169 [In reply to]	Can't Post

kingm316;....

IF you had followed my instructions on how to discharge the 160 vdc (With the set UNPLUGGED) you would NOT have this problem !!!.... Frown

....
Check CR4001 ~ CR4004 , power suppy diodes for shorts....
You might also want to check the board(s) you got from that TV guy for Q4101 & see if it's on the board & IF it's any good.... Laugh

....
Might save you some time & money.... Wink

....

EDIT:=>...

Quote

then i got the new u4101 and installed it along with the 3 new caps, which all came in a kit from acme.

IF you got this kit;=>...

ACME-117 CTC169 repair kit
1 piece TEA2261 (200419)
1 piece SGSIF461 (200165, 203098)<<<<<
1 piece 470mF 35V
1 piece 15mF 63V
1 piece 47mF 50V
1 piece 2.2mF 100v

$ 9.99

You got a NEW Q4101....(SGSIF461)

Post back with results.....

Later...Ron.M.... Cool

....
Veteran & Retired TV technician

(This post was edited by Ron.M on May 7, 2010, 4:48 PM)

kingm316
User

May 1, 2010, 2:14 AM

Post #18 of 115 (7665 views)
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Re: [Ron.M] rca ctc169 [In reply to]	Can't Post

when i ordered the kit the they were out of stock of the sgsif461 and the 35v 470mF cap, i didn't have a problem with it because they refunded the cost of the parts. and the extra board i have the guy already used the q4101. i did take the measurements you asked for and discharged the 160v and made the measurements with it unplugged but while waiting for the parts i ordered i started taking the measurements from the beginning of the posts because i guess i just had to do something while i was waiting for the parts. if the power supply diodes check good are there any voltages i can check with the q4101 removed. if there arn't any checks i can do i will have to learn patience to wait until i get the new transistor.

Ron.M
Veteran

May 1, 2010, 2:35 AM

Post #19 of 115 (7662 views)
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Re: [kingm316] rca ctc169 [In reply to]	Can't Post

kingm316;....

Well , we live & we learn..... Wink

....

Quote

. if the power supply diodes check good are there any
voltages i can check with the q4101 removed.

YES , BUT , I'd rather wait till you get the transistor in....
Do NOT install it till I give you an "all clear"....
We are going to make another check or two....
But , in the interest of safety , leave it ALONE...OK.... Wink

....

Quote

if there arn't any checks i can do i will have to learn patience to wait until i get the new transistor.

PLEASE DO !!!... Laugh

...

In the meantime , contact "acme" & see if you can get an ETA
(Estimated Time of Arrival) for the rest of the parts you need...

We having "fun" yet ???.... Crazy

....

Good Luck..... Smile

....

Later...Ron.M.... Cool

....
Veteran & Retired TV technician

kingm316
User

May 1, 2010, 1:05 PM

Post #20 of 115 (7651 views)
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Re: [Ron.M] rca ctc169 [In reply to]	Can't Post

i checked the power supply diodes with my meter in the diode test mode and all cr1 thru cr4 have 550 in one direction and infinite in the other so i believe they are ok. when i got the other board from the tv guy he said if i have power supply problem i should check cr122, so i did and it was 660 one way and 1530 the other way. i believe those readings mean that one i ok also because it is a zener diode. so when i get a new q4101 you don't want me to install it until you give me the ok, right?

Ron.M
Veteran

May 1, 2010, 5:19 PM

Post #21 of 115 (7644 views)
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Re: [kingm316] rca ctc169 [In reply to]	Can't Post

kingm316;.....

Question;=>...

Quote

so when i get a new q4101 you don't want me to install it until you give me the ok, right?

Answer;=>...

Quote

. if the power supply diodes check good are there any
voltages i can check with the q4101 removed......

YES , BUT , I'd rather wait till you get the transistor in....
>>Do NOT install it till I give you an "all clear"....<<
We are going to make another check or two....
But , in the interest of safety , leave it ALONE...OK.... Wink

....

Quote

check cr122, so i did and it was 660 one way and 1530 the other way.

IF your meter showed .660 & 1,530 using the "diode" scale , then I would say that it's OK...
Notice the period in .660 & the coma in 1,530....
They MUST appear on your meter !!!...

CR4001 ~ CR4004 appear to be OK by what your readings say....

Have you contacted "acme" yet & have you gotten a reply ???

Later...Ron.M.... Cool

....
Veteran & Retired TV technician

kingm316
User

May 1, 2010, 6:05 PM

Post #22 of 115 (7638 views)
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Re: [Ron.M] rca ctc169 [In reply to]	Can't Post

no i havn't called acme but i did stop by a local electronic store and gave him the invoice i got from acme with the sgsif461 number on it and he crossed it to nte2311. the package says "T-NPN, SI, High Voltage/Speed Switch" . is this an acceptable replacement? the electronic store was not a tv supply just a general component store so i just want to be sure. as to the cr122 measurement i don't think it was .660 but i will check it again later today if i can.

Ron.M
Veteran

May 1, 2010, 8:48 PM

Post #23 of 115 (7634 views)
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Re: [kingm316] rca ctc169 [In reply to]	Can't Post

kingm316;....

I'd preffer you get the original type from acme ....
I'm leary of subs for this problem/circuit....
I have the patience to wait a reasonable amount of time for acme to come thru....

Later....Ron.M.... Cool

.....
Veteran & Retired TV technician

kingm316
User

May 2, 2010, 1:23 AM

Post #24 of 115 (7627 views)
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Re: [Ron.M] rca ctc169 [In reply to]	Can't Post

i rechecked the cr122 and the readings were 660 not .660 and 1530. i also checked the other boards cr122 and have almost the same readings. i would guess that they are ok and that maybe my meter just doesn't have the decimal in that area. and then i will have to wait till monday to try and get another transistor.

Ron.M
Veteran

May 2, 2010, 4:53 PM

Post #25 of 115 (7621 views)
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Re: [kingm316] rca ctc169 [In reply to]	Can't Post

kingm316;....

What is the brand & model # of the meter you are using ????....

Later....Ron.M..... Cool

.....
Veteran & Retired TV technician

(This post was edited by Ron.M on May 2, 2010, 4:54 PM)

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