Sentinel TV, model #400-TV help ...

6/12/2005 7:32:01 PMJerry Rappel

I have a Sentinel TV, model #400-TV.
It was given to my wife for me from a friend of hers. I have the photofact/schematic from Sams for it. It's in very good overall condition. (I've been repairing AA5 radios for the past year or so). There's no audio or picture from the TV. Is it worth checking into this TV, checking tubes/filter caps, etc. ??
Never worked on a TV before - I know of the high voltages in there.
Appreciate all help.

Thanks,

Jerry WW0E
ww0e@juno.com

6/12/2005 7:50:56 PMHenry Heuver

:I have a Sentinel TV, model #400-TV.
:It was given to my wife for me from a friend of hers. I have the photofact/schematic from Sams for it. It's in very good overall condition. (I've been repairing AA5 radios for the past year or so). There's no audio or picture from the TV. Is it worth checking into this TV, checking tubes/filter caps, etc. ??
:Never worked on a TV before - I know of the high voltages in there.
:Appreciate all help.
:
:Thanks,
:
:Jerry WW0E
:ww0e@juno.com
:

6/12/2005 7:52:22 PMHenry Heuver

::I have a Sentinel TV, model #400-TV.
::It was given to my wife for me from a friend of hers. I have the photofact/schematic from Sams for it. It's in very good overall condition. (I've been repairing AA5 radios for the past year or so). There's no audio or picture from the TV. Is it worth checking into this TV, checking tubes/filter caps, etc. ??
::Never worked on a TV before - I know of the high voltages in there.
::Appreciate all help.
::
::Thanks,
::
::Jerry WW0E
::ww0e@juno.com
::Dear Jerry:

Does this TV have a power transformer or are all the tube in series? do the tubes light up at all???

Henry

6/12/2005 7:59:17 PMJerry Rappel

:::I have a Sentinel TV, model #400-TV.
:::It was given to my wife for me from a friend of hers. I have the photofact/schematic from Sams for it. It's in very good overall condition. (I've been repairing AA5 radios for the past year or so). There's no audio or picture from the TV. Is it worth checking into this TV, checking tubes/filter caps, etc. ??
:::Never worked on a TV before - I know of the high voltages in there.
:::Appreciate all help.
:::
:::Thanks,
:::
:::Jerry WW0E
:::ww0e@juno.com
:::Dear Jerry:
:
:Does this TV have a power transformer or are all the tube in series? do the tubes light up at all???
:
:Henry

-------------------------------

Yes the tubes light, what I can see without removing the chassis, and yes it has a power xformer. Thanks,

Jerry

6/12/2005 8:35:06 PMHenry Heuver

::::I have a Sentinel TV, model #400-TV.
::::It was given to my wife for me from a friend of hers. I have the photofact/schematic from Sams for it. It's in very good overall condition. (I've been repairing AA5 radios for the past year or so). There's no audio or picture from the TV. Is it worth checking into this TV, checking tubes/filter caps, etc. ??
::::Never worked on a TV before - I know of the high voltages in there.
Boy that was fast.....

Your power supply is not working. This could be just a fuse, power rectifier or another small component.Measure the DC voltage on one of the large capacitors in the power supply.You should get around 300+ volts DC
Try again

Henry

::::Appreciate all help.
::::
::::Thanks,
::::
::::Jerry WW0E
::::ww0e@juno.com
::::Dear Jerry:
::
::Does this TV have a power transformer or are all the tube in series? do the tubes light up at all???
::
::Henry
:
:-------------------------------
:
:Yes the tubes light, what I can see without removing the chassis, and yes it has a power xformer. Thanks,
:
:Jerry

6/13/2005 2:04:30 PMJerry Rappel

:::::I have a Sentinel TV, model #400-TV.
:::::It was given to my wife for me from a friend of hers. I have the photofact/schematic from Sams for it. It's in very good overall condition. (I've been repairing AA5 radios for the past year or so). There's no audio or picture from the TV. Is it worth checking into this TV, checking tubes/filter caps, etc. ??
:::::Never worked on a TV before - I know of the high voltages in there.
:Boy that was fast.....
:
:Your power supply is not working. This could be just a fuse, power rectifier or another small component.Measure the DC voltage on one of the large capacitors in the power supply.You should get around 300+ volts DC
:Try again
:
:Henry
:
:::::Appreciate all help.
:::::
:::::Thanks,
:::::
:::::Jerry WW0E
:::::ww0e@juno.com
:::::Dear Jerry:
:::
:::Does this TV have a power transformer or are all the tube in series? do the tubes light up at all???
:::
:::Henry
::
::-------------------------------
::
::Yes the tubes light, what I can see without removing the chassis, and yes it has a power xformer. Thanks,
::
::Jerry

----------------------

Just started checking the tubes on the 400-TV,
the oscillator tube 12AT7 was replaced by a 6C4 ?
Why was this? All other tubes check out good except for the Vertical Oscillator 6SN7GT.

Jerry WW0E

6/13/2005 3:03:11 PMEdd

***********************************************************************
FIO what Sams number are you using for that set…Sams didn’t list a Sentinel.TV, only CB radios?
As far as the 12AT7 osc , what section is that used in…the tuner…as the 6C4 (7 pin mini) is a “hefty” single section 12AT7 ( 9 pin mini) so to speak with some variance
in the hi freq response if used in an RF application.
As far as the 6SN7 in the vertical application, ( there also might be another of the same tube used for the hoz osc and AFC) along with its companion vert output tube
( 6K6 ?) its failure mode would be in the order of the loss of no vertical sweep with a white line produced across the screen. You probably have no kine high voltage and no raster either in your set. Also, if you don’t even get any white noise from the speaker with the volume up, refer back to your power supply voltages presences.
73’s de Edd
***********************************************************************
::::::I have a Sentinel TV, model #400-TV.
::::::It was given to my wife for me from a friend of hers. I have the photofact/schematic from Sams for it. It's in very good overall condition. (I've been repairing AA5 radios for the past year or so). There's no audio or picture from the TV. Is it worth checking into this TV, checking tubes/filter caps, etc. ??
::::::Never worked on a TV before - I know of the high voltages in there.
::Boy that was fast.....
::
::Your power supply is not working. This could be just a fuse, power rectifier or another small component.Measure the DC voltage on one of the large capacitors in the power supply.You should get around 300+ volts DC
::Try again
::
::Henry
::
::::::Appreciate all help.
::::::
::::::Thanks,
::::::
::::::Jerry WW0E
::::::ww0e@juno.com
::::::Dear Jerry:
::::
::::Does this TV have a power transformer or are all the tube in series? do the tubes light up at all???
::::
::::Henry
:::
:::-------------------------------
:::
:::Yes the tubes light, what I can see without removing the chassis, and yes it has a power xformer. Thanks,
:::
:::Jerry
:
:
:
:----------------------
:
:Just started checking the tubes on the 400-TV,
:the oscillator tube 12AT7 was replaced by a 6C4 ?
:Why was this? All other tubes check out good except for the Vertical Oscillator 6SN7GT.
:
:Jerry WW0E
:

6/13/2005 3:17:30 PMJerry Rappel

:
:
:
:
:***********************************************************************
:FIO what Sams number are you using for that set…Sams didn’t list a Sentinel.TV, only CB radios?
:As far as the 12AT7 osc , what section is that used in…the tuner…as the 6C4 (7 pin mini) is a “hefty” single section 12AT7 ( 9 pin mini) so to speak with some variance
:in the hi freq response if used in an RF application.
:As far as the 6SN7 in the vertical application, ( there also might be another of the same tube used for the hoz osc and AFC) along with its companion vert output tube
:( 6K6 ?) its failure mode would be in the order of the loss of no vertical sweep with a white line produced across the screen. You probably have no kine high voltage and no raster either in your set. Also, if you don’t even get any white noise from the speaker with the volume up, refer back to your power supply voltages presences.
:73’s de Edd
:***********************************************************************
:::::::I have a Sentinel TV, model #400-TV.
:::::::It was given to my wife for me from a friend of hers. I have the photofact/schematic from Sams for it. It's in very good overall condition. (I've been repairing AA5 radios for the past year or so). There's no audio or picture from the TV. Is it worth checking into this TV, checking tubes/filter caps, etc. ??
:::::::Never worked on a TV before - I know of the high voltages in there.
:::Boy that was fast.....
:::
:::Your power supply is not working. This could be just a fuse, power rectifier or another small component.Measure the DC voltage on one of the large capacitors in the power supply.You should get around 300+ volts DC
:::Try again
:::
:::Henry
:::
:::::::Appreciate all help.
:::::::
:::::::Thanks,
:::::::
:::::::Jerry WW0E
:::::::ww0e@juno.com
:::::::Dear Jerry:
:::::
:::::Does this TV have a power transformer or are all the tube in series? do the tubes light up at all???
:::::
:::::Henry
::::
::::-------------------------------
::::
::::Yes the tubes light, what I can see without removing the chassis, and yes it has a power xformer. Thanks,
::::
::::Jerry
::
::
::
::----------------------
::
::Just started checking the tubes on the 400-TV,
::the oscillator tube 12AT7 was replaced by a 6C4 ?
::Why was this? All other tubes check out good except for the Vertical Oscillator 6SN7GT.
::
::Jerry WW0E

--------------------------

It's Sams Photofact #73, folder #11, 10/49,
Sentinel models 400-TV, 405-TVM.
The 12AT7 osc is used in the RF AMP/MIXER/OSC
according to the block diagram.
There is no audio, except for a scratchy/static moise when the volume pot is moved, no picture/raster etc.
This is my first attempt at TV repair ...
I need all the help I can get.
This TV has been here a couple years, just decided to see what I could figure out.

Jerry

6/13/2005 3:35:29 PMThomas Dermody

When is this television from? Is it from 10/49? If so, replace all the condensers before powering it up. Condensers of then did not last long without getting leaky. Once you find your burned out component (fuse?), you may burn something else out when you fire up the set again. If you are getting scratchy sounds from the speaker when you turn the volume, then your amplifier is likely getting some voltage. Since the picture won't light and the RF stages won't bring in anything, it still sounds like there is a power supply issue. Do you hear a hum in the speaker (loud)? Could be either that the part of the supply that powers the amplifier is not broken (if there are different parts or segments), or that the voltage has been reduced enough to not allow function of critical circuits such as picture and RF, but allow some audio function. It does not take much voltage to get a small response out of the audio section. A voltage of only 50 will give you small sounds. This could either be caused by something loading down the supply (shorted condenser, most likely), or by the supply itself failing.

The 6C4 (12AT7) and 6SN7 tubes should not be your concern at this moment. Check all tubes for being weak and possibly replace those that are, but do not expect any changes. Focus your attention to voltages found within the set. Check condensers for leakage and shorting by disconnecting each to be tested, and then using your multi-meter at its most sensitive resistance setting to see if they leak. A good condenser has NO leakage. If it deflects the needle at all, the needle will fall back EXACTLY to where it started after the condenser has charged up from the voltage of your meter. Leakage in the millions of ohms is not likely the cause of your power supply problem, but it will cause trouble down the line in more critical circuits. Certainly leakage in the thousands of ohms or less will cause trouble.

Thomas

6/13/2005 4:02:37 PMJerry Rappel

:When is this television from? Is it from 10/49? If so, replace all the condensers before powering it up. Condensers of then did not last long without getting leaky. Once you find your burned out component (fuse?), you may burn something else out when you fire up the set again. If you are getting scratchy sounds from the speaker when you turn the volume, then your amplifier is likely getting some voltage. Since the picture won't light and the RF stages won't bring in anything, it still sounds like there is a power supply issue. Do you hear a hum in the speaker (loud)? Could be either that the part of the supply that powers the amplifier is not broken (if there are different parts or segments), or that the voltage has been reduced enough to not allow function of critical circuits such as picture and RF, but allow some audio function. It does not take much voltage to get a small response out of the audio section. A voltage of only 50 will give you small sounds. This could either be caused by something loading down the supply (shorted condenser, most likely), or by the supply itself failing.
:
:The 6C4 (12AT7) and 6SN7 tubes should not be your concern at this moment. Check all tubes for being weak and possibly replace those that are, but do not expect any changes. Focus your attention to voltages found within the set. Check condensers for leakage and shorting by disconnecting each to be tested, and then using your multi-meter at its most sensitive resistance setting to see if they leak. A good condenser has NO leakage. If it deflects the needle at all, the needle will fall back EXACTLY to where it started after the condenser has charged up from the voltage of your meter. Leakage in the millions of ohms is not likely the cause of your power supply problem, but it will cause trouble down the line in more critical circuits. Certainly leakage in the thousands of ohms or less will cause trouble.
:
:
:Thomas
------------------------

Yes it's from 1949.
No hum in the speaker.
Thanks,

Jerry

6/13/2005 4:48:49 PMHenry Heuver

::When is this television from? Is it from 10/49? If so, replace all the condensers before powering it up. Condensers of then did not last long without getting leaky. Once you find your burned out component (fuse?), you may burn something else out when you fire up the set again. If you are getting scratchy sounds from the speaker when you turn the volume, then your amplifier is likely getting some voltage. Since the picture won't light and the RF stages won't bring in anything, it still sounds like there is a power supply issue. Do you hear a hum in the speaker (loud)? Could be either that the part of the supply that powers the amplifier is not broken (if there are different parts or segments), or that the voltage has been reduced enough to not allow function of critical circuits such as picture and RF, but allow some audio function. It does not take much voltage to get a small response out of the audio section. A voltage of only 50 will give you small sounds. This could either be caused by something loading down the supply (shorted condenser, most likely), or by the supply itself failing.
::
::The 6C4 (12AT7) and 6SN7 tubes should not be your concern at this moment. Check all tubes for being weak and possibly replace those that are, but do not expect any changes. Focus your attention to voltages found within the set. Check condensers for leakage and shorting by disconnecting each to be tested, and then using your multi-meter at its most sensitive resistance setting to see if they leak. A good condenser has NO leakage. If it deflects the needle at all, the needle will fall back EXACTLY to where it started after the condenser has charged up from the voltage of your meter. Leakage in the millions of ohms is not likely the cause of your power supply problem, but it will cause trouble down the line in more critical circuits. Certainly leakage in the thousands of ohms or less will cause trouble.
::
::
::Thomas
:------------------------
:
:Yes it's from 1949.
:No hum in the speaker.
:Thanks,
:
:
:dear Jerry:

all the information provided gets very confusing.
Since you don't even get audio, I still maintain that the problem lies with your power supply. ccheck the DC voltages on you electrolytic condensers( These are the big, aluminum cans usually mounted on the chassis)
Do you know the model number and do you have a schematic???

henry

6/13/2005 5:39:01 PMJerry Rappel

:::When is this television from? Is it from 10/49? If so, replace all the condensers before powering it up. Condensers of then did not last long without getting leaky. Once you find your burned out component (fuse?), you may burn something else out when you fire up the set again. If you are getting scratchy sounds from the speaker when you turn the volume, then your amplifier is likely getting some voltage. Since the picture won't light and the RF stages won't bring in anything, it still sounds like there is a power supply issue. Do you hear a hum in the speaker (loud)? Could be either that the part of the supply that powers the amplifier is not broken (if there are different parts or segments), or that the voltage has been reduced enough to not allow function of critical circuits such as picture and RF, but allow some audio function. It does not take much voltage to get a small response out of the audio section. A voltage of only 50 will give you small sounds. This could either be caused by something loading down the supply (shorted condenser, most likely), or by the supply itself failing.
:::
:::The 6C4 (12AT7) and 6SN7 tubes should not be your concern at this moment. Check all tubes for being weak and possibly replace those that are, but do not expect any changes. Focus your attention to voltages found within the set. Check condensers for leakage and shorting by disconnecting each to be tested, and then using your multi-meter at its most sensitive resistance setting to see if they leak. A good condenser has NO leakage. If it deflects the needle at all, the needle will fall back EXACTLY to where it started after the condenser has charged up from the voltage of your meter. Leakage in the millions of ohms is not likely the cause of your power supply problem, but it will cause trouble down the line in more critical circuits. Certainly leakage in the thousands of ohms or less will cause trouble.
:::
:::
:::Thomas
::------------------------
::
::Yes it's from 1949.
::No hum in the speaker.
::Thanks,
::
::
::dear Jerry:
:
:all the information provided gets very confusing.
:Since you don't even get audio, I still maintain that the problem lies with your power supply. ccheck the DC voltages on you electrolytic condensers( These are the big, aluminum cans usually mounted on the chassis)
:Do you know the model number and do you have a schematic???
:
:henry

6/13/2005 5:41:06 PMJerry Rappel

::::When is this television from? Is it from 10/49? If so, replace all the condensers before powering it up. Condensers of then did not last long without getting leaky. Once you find your burned out component (fuse?), you may burn something else out when you fire up the set again. If you are getting scratchy sounds from the speaker when you turn the volume, then your amplifier is likely getting some voltage. Since the picture won't light and the RF stages won't bring in anything, it still sounds like there is a power supply issue. Do you hear a hum in the speaker (loud)? Could be either that the part of the supply that powers the amplifier is not broken (if there are different parts or segments), or that the voltage has been reduced enough to not allow function of critical circuits such as picture and RF, but allow some audio function. It does not take much voltage to get a small response out of the audio section. A voltage of only 50 will give you small sounds. This could either be caused by something loading down the supply (shorted condenser, most likely), or by the supply itself failing.
::::
::::The 6C4 (12AT7) and 6SN7 tubes should not be your concern at this moment. Check all tubes for being weak and possibly replace those that are, but do not expect any changes. Focus your attention to voltages found within the set. Check condensers for leakage and shorting by disconnecting each to be tested, and then using your multi-meter at its most sensitive resistance setting to see if they leak. A good condenser has NO leakage. If it deflects the needle at all, the needle will fall back EXACTLY to where it started after the condenser has charged up from the voltage of your meter. Leakage in the millions of ohms is not likely the cause of your power supply problem, but it will cause trouble down the line in more critical circuits. Certainly leakage in the thousands of ohms or less will cause trouble.
::::
::::
::::Thomas
:::------------------------
:::
:::Yes it's from 1949.
:::No hum in the speaker.
:::Thanks,
:::
:::
:::dear Jerry:
::
::all the information provided gets very confusing.
::Since you don't even get audio, I still maintain that the problem lies with your power supply. ccheck the DC voltages on you electrolytic condensers( These are the big, aluminum cans usually mounted on the chassis)
::Do you know the model number and do you have a schematic???
::
::henry
--------------------------
Sentinel TV - model #400-TV.
Yes I have the schematic, I check the electrolytic condensers and let you know what I find.

Jerry

6/13/2005 9:05:02 PMJerry Rappel

:::::When is this television from? Is it from 10/49? If so, replace all the condensers before powering it up. Condensers of then did not last long without getting leaky. Once you find your burned out component (fuse?), you may burn something else out when you fire up the set again. If you are getting scratchy sounds from the speaker when you turn the volume, then your amplifier is likely getting some voltage. Since the picture won't light and the RF stages won't bring in anything, it still sounds like there is a power supply issue. Do you hear a hum in the speaker (loud)? Could be either that the part of the supply that powers the amplifier is not broken (if there are different parts or segments), or that the voltage has been reduced enough to not allow function of critical circuits such as picture and RF, but allow some audio function. It does not take much voltage to get a small response out of the audio section. A voltage of only 50 will give you small sounds. This could either be caused by something loading down the supply (shorted condenser, most likely), or by the supply itself failing.
:::::
:::::The 6C4 (12AT7) and 6SN7 tubes should not be your concern at this moment. Check all tubes for being weak and possibly replace those that are, but do not expect any changes. Focus your attention to voltages found within the set. Check condensers for leakage and shorting by disconnecting each to be tested, and then using your multi-meter at its most sensitive resistance setting to see if they leak. A good condenser has NO leakage. If it deflects the needle at all, the needle will fall back EXACTLY to where it started after the condenser has charged up from the voltage of your meter. Leakage in the millions of ohms is not likely the cause of your power supply problem, but it will cause trouble down the line in more critical circuits. Certainly leakage in the thousands of ohms or less will cause trouble.
:::::
:::::
:::::Thomas
::::------------------------
::::
::::Yes it's from 1949.
::::No hum in the speaker.
::::Thanks,
::::
::::
::::dear Jerry:
:::
:::all the information provided gets very confusing.
:::Since you don't even get audio, I still maintain that the problem lies with your power supply. ccheck the DC voltages on you electrolytic condensers( These are the big, aluminum cans usually mounted on the chassis)
:::Do you know the model number and do you have a schematic???
:::
:::henry
:--------------------------
:Sentinel TV - model #400-TV.
:Yes I have the schematic, I check the electrolytic condensers and let you know what I find.
:
:Jerry

------------------------------------------

I'm getting no DC voltage reading from the electrolytic condensers, I'm considering parting out the 1949 Sentinel 400-TV, it appears it'll take too much time to try and figure this one out.
Any interest?

Jerry WW0E
ww0e@juno.com

6/14/2005 11:37:28 PMHenry Heuver

::::::When is this television from? Is it from 10/49? If so, replace all the condensers before powering it up. Condensers of then did not last long without getting leaky. Once you find your burned out component (fuse?), you may burn something else out when you fire up the set again. If you are getting scratchy sounds from the speaker when you turn the volume, then your amplifier is likely getting some voltage. Since the picture won't light and the RF stages won't bring in anything, it still sounds like there is a power supply issue. Do you hear a hum in the speaker (loud)? Could be either that the part of the supply that powers the amplifier is not broken (if there are different parts or segments), or that the voltage has been reduced enough to not allow function of critical circuits such as picture and RF, but allow some audio function. It does not take much voltage to get a small response out of the audio section. A voltage of only 50 will give you small sounds. This could either be caused by something loading down the supply (shorted condenser, most likely), or by the supply itself failing.
::::::
::::::The 6C4 (12AT7) and 6SN7 tubes should not be your concern at this moment. Check all tubes for being weak and possibly replace those that are, but do not expect any changes. Focus your attention to voltages found within the set. Check condensers for leakage and shorting by disconnecting each to be tested, and then using your multi-meter at its most sensitive resistance setting to see if they leak. A good condenser has NO leakage. If it deflects the needle at all, the needle will fall back EXACTLY to where it started after the condenser has charged up from the voltage of your meter. Leakage in the millions of ohms is not likely the cause of your power supply problem, but it will cause trouble down the line in more critical circuits. Certainly leakage in the thousands of ohms or less will cause trouble.
::::::
::::::
::::::Thomas
:::::------------------------
:::::
:::::Yes it's from 1949.
:::::No hum in the speaker.
:::::Thanks,
:::::
:::::
:::::dear Jerry:
::::
::::all the information provided gets very confusing.
::::Since you don't even get audio, I still maintain that the problem lies with your power supply. ccheck the DC voltages on you electrolytic condensers( These are the big, aluminum cans usually mounted on the chassis)
::::Do you know the model number and do you have a schematic???
::::
::::henry
::--------------------------
::Sentinel TV - model #400-TV.
::Yes I have the schematic, I check the electrolytic condensers and let you know what I find.
::
::Jerry
:
:------------------------------------------
:
:I'm getting no DC voltage reading from the electrolytic condensers, I'm considering parting out the 1949 Sentinel 400-TV, it appears it'll take too much time to try and figure this one out.
:Any interest?
:
:Jerry WW0E
:ww0e@juno.com
:Hi Jerry:

Your problem is with the power supply.
Check: fuses, rectifier tube or power transformer>
Which rectifier tube is used and do you get AC voltage
on the the connections on the rectifier tube?
If you give me the rectifier tube #, I can tell you which connection to test.

Henry

6/15/2005 10:01:08 AMJerry Rappel

:::::::When is this television from? Is it from 10/49? If so, replace all the condensers before powering it up. Condensers of then did not last long without getting leaky. Once you find your burned out component (fuse?), you may burn something else out when you fire up the set again. If you are getting scratchy sounds from the speaker when you turn the volume, then your amplifier is likely getting some voltage. Since the picture won't light and the RF stages won't bring in anything, it still sounds like there is a power supply issue. Do you hear a hum in the speaker (loud)? Could be either that the part of the supply that powers the amplifier is not broken (if there are different parts or segments), or that the voltage has been reduced enough to not allow function of critical circuits such as picture and RF, but allow some audio function. It does not take much voltage to get a small response out of the audio section. A voltage of only 50 will give you small sounds. This could either be caused by something loading down the supply (shorted condenser, most likely), or by the supply itself failing.
:::::::
:::::::The 6C4 (12AT7) and 6SN7 tubes should not be your concern at this moment. Check all tubes for being weak and possibly replace those that are, but do not expect any changes. Focus your attention to voltages found within the set. Check condensers for leakage and shorting by disconnecting each to be tested, and then using your multi-meter at its most sensitive resistance setting to see if they leak. A good condenser has NO leakage. If it deflects the needle at all, the needle will fall back EXACTLY to where it started after the condenser has charged up from the voltage of your meter. Leakage in the millions of ohms is not likely the cause of your power supply problem, but it will cause trouble down the line in more critical circuits. Certainly leakage in the thousands of ohms or less will cause trouble.
:::::::
:::::::
:::::::Thomas
::::::------------------------
::::::
::::::Yes it's from 1949.
::::::No hum in the speaker.
::::::Thanks,
::::::
::::::
::::::dear Jerry:
:::::
:::::all the information provided gets very confusing.
:::::Since you don't even get audio, I still maintain that the problem lies with your power supply. ccheck the DC voltages on you electrolytic condensers( These are the big, aluminum cans usually mounted on the chassis)
:::::Do you know the model number and do you have a schematic???
:::::
:::::henry
:::--------------------------
:::Sentinel TV - model #400-TV.
:::Yes I have the schematic, I check the electrolytic condensers and let you know what I find.
:::
:::Jerry
::
::------------------------------------------
::
::I'm getting no DC voltage reading from the electrolytic condensers, I'm considering parting out the 1949 Sentinel 400-TV, it appears it'll take too much time to try and figure this one out.
::Any interest?
::
::Jerry WW0E
::ww0e@juno.com
::Hi Jerry:
:
:Your problem is with the power supply.
:Check: fuses, rectifier tube or power transformer>
:Which rectifier tube is used and do you get AC voltage
:on the the connections on the rectifier tube?
:If you give me the rectifier tube #, I can tell you which connection to test.
:
:Henry
-----------------------

OK Henry,
1B3GT is the HV Rectifier, and 6X5GT is the LV Rectifier, yes please tell me which connections to test. Yes I'm getting AC.

Thanks,

Jerry

6/15/2005 1:45:46 PMHenry Heuver

::::::::When is this television from? Is it from 10/49? If so, replace all the condensers before powering it up. Condensers of then did not last long without getting leaky. Once you find your burned out component (fuse?), you may burn something else out when you fire up the set again. If you are getting scratchy sounds from the speaker when you turn the volume, then your amplifier is likely getting some voltage. Since the picture won't light and the RF stages won't bring in anything, it still sounds like there is a power supply issue. Do you hear a hum in the speaker (loud)? Could be either that the part of the supply that powers the amplifier is not broken (if there are different parts or segments), or that the voltage has been reduced enough to not allow function of critical circuits such as picture and RF, but allow some audio function. It does not take much voltage to get a small response out of the audio section. A voltage of only 50 will give you small sounds. This could either be caused by something loading down the supply (shorted condenser, most likely), or by the supply itself failing.
::::::::
::::::::The 6C4 (12AT7) and 6SN7 tubes should not be your concern at this moment. Check all tubes for being weak and possibly replace those that are, but do not expect any changes. Focus your attention to voltages found within the set. Check condensers for leakage and shorting by disconnecting each to be tested, and then using your multi-meter at its most sensitive resistance setting to see if they leak. A good condenser has NO leakage. If it deflects the needle at all, the needle will fall back EXACTLY to where it started after the condenser has charged up from the voltage of your meter. Leakage in the millions of ohms is not likely the cause of your power supply problem, but it will cause trouble down the line in more critical circuits. Certainly leakage in the thousands of ohms or less will cause trouble.
::::::::
::::::::
::::::::Thomas
:::::::------------------------
:::::::
:::::::Yes it's from 1949.
:::::::No hum in the speaker.
:::::::Thanks,
:::::::
:::::::
:::::::dear Jerry:
::::::
::::::all the information provided gets very confusing.
::::::Since you don't even get audio, I still maintain that the problem lies with your power supply. ccheck the DC voltages on you electrolytic condensers( These are the big, aluminum cans usually mounted on the chassis)
::::::Do you know the model number and do you have a schematic???
::::::
::::::henry
::::--------------------------
::::Sentinel TV - model #400-TV.
::::Yes I have the schematic, I check the electrolytic condensers and let you know what I find.
::::
::::Jerry
:::
:::------------------------------------------
:::
:::I'm getting no DC voltage reading from the electrolytic condensers, I'm considering parting out the 1949 Sentinel 400-TV, it appears it'll take too much time to try and figure this one out.
:::Any interest?
:::
:::Jerry WW0E
:::ww0e@juno.com
:::Hi Jerry:
::
::Your problem is with the power supply.
::Check: fuses, rectifier tube or power transformer>
::Which rectifier tube is used and do you get AC voltage
::on the the connections on the rectifier tube?
::If you give me the rectifier tube #, I can tell you which connection to test.
::
::Henry
:-----------------------
:
:OK Henry,
:1B3GT is the HV Rectifier, and 6X5GT is the LV Rectifier, yes please tell me which connections to test. Yes I'm getting AC.
:
:Thanks,
:
:Jerry
:Hi Jerry:
You should get around 300Volt AC on pins 3 and 5 of your 6X5 rectifier.Then check your DC voltage on pin 8.
If you get the first reading but no voltage on pin 8, then the tube is shot. Good luck....
Henry