Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

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Old September 24th 03, 05:42 PM
 
Posts: n/a
Default more info RCA TV CTC169(BG5) Wont come out of standby - Ticking sound when Power button is pressed

Hi all-

Nearly as I can tell, there is both a separate audio board and a separate SRS board (F35750ST CTC160BG5). Both boards have no power, because I disconnected connectors 1903 and 1904.

There does not appear to be a separate Focus and screen Block. By the IVHT (attached to the back) is a white box with 4 wires and 2 pots inside.

SMPS voltages appear good, but no start-up, and still hear the ticking sound.

Really appreciate the help, just want to keep it going for a few more months……..

Mark

```````````````````````````````````````````
From: (TV Fixer1)
Newsgroups: sci.electronics.repair
Date: 24 Sep 2003 15:37:23 GMT
Subject: more info RCA TV CTC169(BG5) Wont come out of standby - Ticking sound when Power button is pressed

I think the 169 chassis has the audio module soldered to the main board, but I
have seen blown audio IC's cause no startup; desoldering the IC pins from their
pads should temporarily work, if that's the problem.


**********End Of Post*************
Reply-To: "john"
From: "john"

Does this set have the add on Focus and Screen block
if it does you cannot miss it .Its a Black unit which sits
above the IHVT .


kip

--
"Watch the return E-Mail addy its false"
wrote in message
...
Thanks. I neglected to mention that I tried that, with no luck. Same

problem. I had also pulled all of the other plugs
associated with the PS. I'm not giving up yet... it is pi**ing me off

now...

Mark

Subject: more info RCA TV CTC169(BG5) Wont come out of standby -

Ticking sound when Power button is pressed

Disconnect the plug in lead which goes to the sound board then try it.


kip

--
"Watch the return E-Mail addy its false"
wrote in message
...
Thank you all for the help.

I did replace the 15uF cap. Now I have replaced all 4 caps in the SMPS,

and CR4118.

In addition, I repaired cracked solder joints on the 1.8 ohm resistor,

replaced the thermistor (broken), and CR4120 (blown apart). Because I saw

a
puff of smoke from the C4112 / T4101 area, I replaced both of those. No
change. 12.7 / 141 is fine, but it wont come out of standby, and it makes

a
ticking sound while the power button is pressed.

More data:
With the collector of the Q4401 HOT unsoldered, the voltage on the

collector lead is 0.5V, and on the circuit board pad it is 140V.
Standby voltages are 12.7 / 141V, set wont come out of standby,
BUT there is no ticking sound.

With the collector soldered in, voltage at Q4401 collector measures

140V.

I also re-replaced CR4118 with a different style ECG580. Voltages are

still steady at 12.7 and 141.

So far, I fixed the cold solder joint on the power resistor, replaced

the
diodes and caps around the smps, in addition to the misc parts above.

Still
a ticking sound while the power button is pressed......Seems like the SMPS
is fine....

I really appreciate your help. I dont want to replace the TV unless I

have to!!!!!!!

Thanks again-

Mark

````````````````````````````````````````````````

I had intended on replacing C4104, but the shop had the wrong part in

the
kit -
(he had [email protected]). I'll get the correct part. I'll also pick up the

other cap, C4118 ([email protected]).

After replacing the 2 caps, I'll try pulling the collector on the HOT.

BTW, What would happen if C4112 or T4101 was fried? I did see a puff

of
smoke from that area.


I'll look at junk chassis and tell you about it tomorrow night.

Cheers,

Wizard
`````````````````````````````````````````````````` `````
On Mon, 22 Sep 2003 00:12:25 GMT,
wrote:

Hi all-

I have an RCA 35" direct view TV. It wont come out of standby.
When the power button is pressed a ticking sound is heard - only while

the button is pressed.

Upon inspection, R4001 (1.8 15W) resistor was found to have
cracked solder joints. RT 4201 was replaced because it came apart.
CR4120 was replaced because it was physically blown.


This is very clear case that it might had surge or horizontal circuit
blew in turn blew the SMPS.


CR4118 was replaced, along with C4102 ([email protected])
and C4108 (replaced with [email protected]) in an attempt tp fix this problem.


There are four electrolytic capacitors in SMPS, missed 15uF 100V and
470uF 35V replace them, change 47uF to 39uF 100V this helps the SMPS
to run cooler, was running change during CTC169 production. This cap
is in series from SMPS IC to this base of SMPS Q4101 transistor.


Standby voltage is 143V at TP 4101, and +15 standby is 12.7V at TP4103.
When power button is pressed, both voltages drop (143 down to 110, 127.

drops to 10V).

Both volts are good in standby. But you still have a problem in run
mode. Unsolder collector of the HOT (Q4401) and try again. If TV
stays on without ticking, this means either flyback transformer,
focus/G2 screen block or tube is bad.

Carefully decide if this set is worth fixing because most of them I
fixed in 35" size like this tube were usually used up and new tube for
this is over 1,400. New set is best.

The flyback is about $120 retail.

Decide real carefully.

Cheers,

Wizard






  #2   Report Post  
Old September 24th 03, 05:42 PM
 
Posts: n/a
Default more info RCA TV CTC169(BG5) Wont come out of standby - Ticking sound when Power button is pressed

Hi all-

Nearly as I can tell, there is both a separate audio board and a separate SRS board (F35750ST CTC160BG5). Both boards have no power, because I disconnected connectors 1903 and 1904.

There does not appear to be a separate Focus and screen Block. By the IVHT (attached to the back) is a white box with 4 wires and 2 pots inside.

SMPS voltages appear good, but no start-up, and still hear the ticking sound.

Really appreciate the help, just want to keep it going for a few more months……..

Mark

```````````````````````````````````````````
From: (TV Fixer1)
Newsgroups: sci.electronics.repair
Date: 24 Sep 2003 15:37:23 GMT
Subject: more info RCA TV CTC169(BG5) Wont come out of standby - Ticking sound when Power button is pressed

I think the 169 chassis has the audio module soldered to the main board, but I
have seen blown audio IC's cause no startup; desoldering the IC pins from their
pads should temporarily work, if that's the problem.


**********End Of Post*************
Reply-To: "john"
From: "john"

Does this set have the add on Focus and Screen block
if it does you cannot miss it .Its a Black unit which sits
above the IHVT .


kip

--
"Watch the return E-Mail addy its false"
wrote in message
...
Thanks. I neglected to mention that I tried that, with no luck. Same

problem. I had also pulled all of the other plugs
associated with the PS. I'm not giving up yet... it is pi**ing me off

now...

Mark

Subject: more info RCA TV CTC169(BG5) Wont come out of standby -

Ticking sound when Power button is pressed

Disconnect the plug in lead which goes to the sound board then try it.


kip

--
"Watch the return E-Mail addy its false"
wrote in message
...
Thank you all for the help.

I did replace the 15uF cap. Now I have replaced all 4 caps in the SMPS,

and CR4118.

In addition, I repaired cracked solder joints on the 1.8 ohm resistor,

replaced the thermistor (broken), and CR4120 (blown apart). Because I saw

a
puff of smoke from the C4112 / T4101 area, I replaced both of those. No
change. 12.7 / 141 is fine, but it wont come out of standby, and it makes

a
ticking sound while the power button is pressed.

More data:
With the collector of the Q4401 HOT unsoldered, the voltage on the

collector lead is 0.5V, and on the circuit board pad it is 140V.
Standby voltages are 12.7 / 141V, set wont come out of standby,
BUT there is no ticking sound.

With the collector soldered in, voltage at Q4401 collector measures

140V.

I also re-replaced CR4118 with a different style ECG580. Voltages are

still steady at 12.7 and 141.

So far, I fixed the cold solder joint on the power resistor, replaced

the
diodes and caps around the smps, in addition to the misc parts above.

Still
a ticking sound while the power button is pressed......Seems like the SMPS
is fine....

I really appreciate your help. I dont want to replace the TV unless I

have to!!!!!!!

Thanks again-

Mark

````````````````````````````````````````````````

I had intended on replacing C4104, but the shop had the wrong part in

the
kit -
(he had [email protected]). I'll get the correct part. I'll also pick up the

other cap, C4118 ([email protected]).

After replacing the 2 caps, I'll try pulling the collector on the HOT.

BTW, What would happen if C4112 or T4101 was fried? I did see a puff

of
smoke from that area.


I'll look at junk chassis and tell you about it tomorrow night.

Cheers,

Wizard
`````````````````````````````````````````````````` `````
On Mon, 22 Sep 2003 00:12:25 GMT,
wrote:

Hi all-

I have an RCA 35" direct view TV. It wont come out of standby.
When the power button is pressed a ticking sound is heard - only while

the button is pressed.

Upon inspection, R4001 (1.8 15W) resistor was found to have
cracked solder joints. RT 4201 was replaced because it came apart.
CR4120 was replaced because it was physically blown.


This is very clear case that it might had surge or horizontal circuit
blew in turn blew the SMPS.


CR4118 was replaced, along with C4102 ([email protected])
and C4108 (replaced with [email protected]) in an attempt tp fix this problem.


There are four electrolytic capacitors in SMPS, missed 15uF 100V and
470uF 35V replace them, change 47uF to 39uF 100V this helps the SMPS
to run cooler, was running change during CTC169 production. This cap
is in series from SMPS IC to this base of SMPS Q4101 transistor.


Standby voltage is 143V at TP 4101, and +15 standby is 12.7V at TP4103.
When power button is pressed, both voltages drop (143 down to 110, 127.

drops to 10V).

Both volts are good in standby. But you still have a problem in run
mode. Unsolder collector of the HOT (Q4401) and try again. If TV
stays on without ticking, this means either flyback transformer,
focus/G2 screen block or tube is bad.

Carefully decide if this set is worth fixing because most of them I
fixed in 35" size like this tube were usually used up and new tube for
this is over 1,400. New set is best.

The flyback is about $120 retail.

Decide real carefully.

Cheers,

Wizard





  #3   Report Post  
Old September 25th 03, 01:29 AM
Jason D.
 
Posts: n/a
Default more info RCA TV CTC169(BG5) Wont come out of standby - Ticking sound when Power button is pressed

On Wed, 24 Sep 2003 16:42:32 GMT,
wrote:

Hi all-

Nearly as I can tell, there is both a separate audio board and a separate SRS board (F35750ST CTC160BG5). Both boards have no power, because I disconnected connectors 1903 and 1904.

There does not appear to be a separate Focus and screen Block. By the IVHT (attached to the back) is a white box with 4 wires and 2 pots inside.

SMPS voltages appear good, but no start-up, and still hear the ticking sound.

Really appreciate the help, just want to keep it going for a few more months……..

Mark


Mark,

Good progess on the SMPS. Before confirming the flyback is dud, needs
to check all diodes off the flyback isn't leaky or shorted. Need a
scope, lay the probe parallel next to the flyback ferrite core with
low volts/div on the scope and watch that scope while turning set on,
if fly is bad, the scope will show noise (arcing) in time with ticking
not the nice tall thin arches at 15.7 Khz.

Otherwise flyback is bad which is appox 60 to 100 in your area.
Focus/screen block is seperate from flyback. Solder that grey wire &
clean up all flux in focus/screen block with pure actone carefully
when you're changing the flyback.

I occassionally see this happen because the HV tripler (built into fly
itself) fry when SMPS B+ is high for too long due to capacitors in hot
side SMPS.
Same story with HV dividers in ctc169-based projectors.

Cheers,

Wizard
  #4   Report Post  
Old September 25th 03, 01:29 AM
Jason D.
 
Posts: n/a
Default more info RCA TV CTC169(BG5) Wont come out of standby - Ticking sound when Power button is pressed

On Wed, 24 Sep 2003 16:42:32 GMT,
wrote:

Hi all-

Nearly as I can tell, there is both a separate audio board and a separate SRS board (F35750ST CTC160BG5). Both boards have no power, because I disconnected connectors 1903 and 1904.

There does not appear to be a separate Focus and screen Block. By the IVHT (attached to the back) is a white box with 4 wires and 2 pots inside.

SMPS voltages appear good, but no start-up, and still hear the ticking sound.

Really appreciate the help, just want to keep it going for a few more months……..

Mark


Mark,

Good progess on the SMPS. Before confirming the flyback is dud, needs
to check all diodes off the flyback isn't leaky or shorted. Need a
scope, lay the probe parallel next to the flyback ferrite core with
low volts/div on the scope and watch that scope while turning set on,
if fly is bad, the scope will show noise (arcing) in time with ticking
not the nice tall thin arches at 15.7 Khz.

Otherwise flyback is bad which is appox 60 to 100 in your area.
Focus/screen block is seperate from flyback. Solder that grey wire &
clean up all flux in focus/screen block with pure actone carefully
when you're changing the flyback.

I occassionally see this happen because the HV tripler (built into fly
itself) fry when SMPS B+ is high for too long due to capacitors in hot
side SMPS.
Same story with HV dividers in ctc169-based projectors.

Cheers,

Wizard


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