CTC177BE Dead. Relay Clicks 3 Times Model F27630
 

Came in dead with no click. Replaced shorted HOUT but it blew instantly
at turn on. Then replaced fly & HOUT but then only got the relay
clicking 3 times. Came across a sym/cure about horizontal being out of
phase because of a corrupted eprom so I tried jumping C4402 with an
identical .015 cap and now the set does turn on with a good picture
(except of course for the bending pincushion effect because of the
jumped caps). I tried a new eprom but still have the same problem. So
the current status is that it powers up when C4402 is jumped but it
doesn't power up when not jumped and a new eprom didn't solve the
problem. Any suggestions are greatly appreciated. Thanks, Mark

Think about your problem.
If it is not the frequency, then it is the tank.
Good chance a capacitor is way off value, bad replacement flyback, or
something else like the yoke is throwing the whole center frequency of
the tank off.

Troubleshoot from that direction and see what you get.

Nobody in there right mind would jump that .015 cap..
Why don't you do some serious trouble shooting in that section
first change the .015 and did you put in exactly the same HOT Trany ?
What are the voltages measuring ..??Give some useful information.

kip
"MarkC" wrote in message
...
Came in dead with no click. Replaced shorted HOUT but it blew instantly
at turn on. Then replaced fly & HOUT but then only got the relay
clicking 3 times. Came across a sym/cure about horizontal being out of
phase because of a corrupted eprom so I tried jumping C4402 with an
identical .015 cap and now the set does turn on with a good picture
(except of course for the bending pincushion effect because of the
jumped caps). I tried a new eprom but still have the same problem. So
the current status is that it powers up when C4402 is jumped but it
doesn't power up when not jumped and a new eprom didn't solve the
problem. Any suggestions are greatly appreciated. Thanks, Mark

The .015 was just jumped temporarily to access the service menu to check
the horizontal parameters. The HOUT & fly were replaced with identical
OEM parts.

"Nobody in there right mind would jump that .015 cap.. Why don't you do
some serious trouble shooting in that section first change the .015 and
did you put in exactly the same HOT Trany ? What are the voltages
measuring ..??Give some useful information."

Well if you are not going about it the correct Have Fun.

kip
"MarkC" wrote in message
...
The .015 was just jumped temporarily to access the service menu to check
the horizontal parameters. The HOUT & fly were replaced with identical
OEM parts.

"Nobody in there right mind would jump that .015 cap.. Why don't you do
some serious trouble shooting in that section first change the .015 and
did you put in exactly the same HOT Trany ? What are the voltages
measuring ..??Give some useful information."

Thank you all for your help so far.
I'm getting 170V at the collector of the HOUT but still can't find out
what's causing this unregulated voltage. I replaced the STK reg U4101
and the caps C4107 & C4105 and diode CR4106 but no help. How often does
T4101 go bad?
Mark

Forgot to add that I also replaced C4402 & CR4704

Check the parts tied to pins 1 & 2 of the regulator.

Leonard

"MarkC" wrote in message
...
Thank you all for your help so far.
I'm getting 170V at the collector of the HOUT but still can't find out
what's causing this unregulated voltage. I replaced the STK reg U4101
and the caps C4107 & C4105 and diode CR4106 but no help. How often does
T4101 go bad?
Mark

What is the voltage on the collector of the HOT whilst plugged in but NOT
turned on.

kip


"MarkC" wrote in message
...
Thank you all for your help so far.
I'm getting 170V at the collector of the HOUT but still can't find out
what's causing this unregulated voltage. I replaced the STK reg U4101
and the caps C4107 & C4105 and diode CR4106 but no help. How often does
T4101 go bad?
Mark

On Fri, 26 Aug 2005 19:53:24 -0500, (MarkC) put
finger to keyboard and composed:

Came in dead with no click. Replaced shorted HOUT but it blew instantly
at turn on. Then replaced fly & HOUT but then only got the relay
clicking 3 times. Came across a sym/cure about horizontal being out of
phase because of a corrupted eprom so I tried jumping C4402 with an
identical .015 cap and now the set does turn on with a good picture
(except of course for the bending pincushion effect because of the
jumped caps). I tried a new eprom but still have the same problem. So
the current status is that it powers up when C4402 is jumped but it
doesn't power up when not jumped and a new eprom didn't solve the
problem. Any suggestions are greatly appreciated. Thanks, Mark

Is C4402 the tuning cap, ie is it connected to the collector of the
HOT? If so, and if this cap is open or low in value, then the voltage
on the collector is probably rising high enough to trigger the set
into protection mode. This voltage may also exceed the Vce rating of
the HOT.


- Franc Zabkar
--
Please remove one 's' from my address when replying by email.

Did some further troubleshooting. Replaced T4101 but no help.
I'm now getting 350V at the cathode and collector of HOUT while in the
standby mode.

And which ground are you using as a reference when you measured
350V!!!!!!?

I get 160V at pin 11 of U4101 using isolated ground and aorund 375V B+
at the cathode of CR4106 at cold ground in the standby mode. I remember
running into this problem before but forgot what I did to fix it.

"And which ground are you using as a reference when you measured
350V!!!!!!?"

You can be sure that the filter capacitor on the 140V b+ line is now
bad.
Either u4101 is bad or it is missing the feedback voltage used for
regulation.
Do you have the schematic?

Generic ctc177 power supply schematic available at
alt.binaries.schematics.electronic

U4101 was replaced so it must be missing the feedback voltage. I do have
a Sams for it.

"You can be sure that the filter capacitor on the 140V b+ line is now
bad.
Either u4101 is bad or it is missing the feedback voltage used for
regulation.
Do you have the schematic?"

It could actually be missing the reference voltage as well on the input
to the internal comparator. I like the training manual schematic for
troubleshooting as it is easy to figure out what is suppose to be going
on.

I have never seen the reference voltage circuit go bad, just the
feedback line.

On 27 Aug 2005 17:12:01 -0700, "
wrote:

Generic ctc177 power supply schematic available at
alt.binaries.schematics.electronic


This type of SMPS based on STK730-xxx uses one winding on this
transformer (hot side only) for regulation feedback.

The STK730 is triggering on bogus feedback (weak voltage) that makes
output rocket to the moon. :) Change 10uF 63V cap, and very, very
carefully check the feedback circuit for loss of feedback strength.

When you say isolated ground in reference to measuring items, I assume
cold side, hence the confusion for all of us including you. Measure
always in same side hot ground for hot or cold ground for cold. Not
across, this will gave you bogus readings. This is reason to use
isolation transformer while messing in any chassis that has no
insulated & isolated power. SMPS and hot chassis (like CTC185) is not
isolated bec the hot side is still exposed.

Cheers, Wizard

Dave,
I never got to Thank you for the information on repairing a dead set CTC177.
It was about 2 years ago and the information placed on Sam's Website took me
right to the problem (Tuner Ground). I resoldered it with normal solder and
it has worked finr since. It is used daily in my home. Thank you very much
for the big help you provide !!!!!
wrote in message
ups.com...
Generic ctc177 power supply schematic available at
alt.binaries.schematics.electronic