Philco Predicta 10L43

9/14/2006 2:41:11 PMDave Froehlich

Hello All,
I restored this tv and it continues to operate however, one of the resistors overheats and smokes. This resistor (R15A) is connected to the width control on one end. Also, I may have made a mistake when replacing C16, which is nearby. But I don't think that it would cause this problem. Pictures of the PC Board would help here.

Thanks,

Dave

9/14/2006 5:49:09 PMEdd

It doesn't look like your referred R15 or C16 are either in the "width" circuitry, that is
considering that they are in actuality THE Philco part number designations that might be
silk screened on a PCB.Here are two thumbnails of both the IF circitry where those
part designators are valid and used . As well the more probable thumbnail specifics
of the hoz output section and the technique used for width regulation...e.g. the contrl of the
screen grid supply voltage of the HOT.

Stand waaaaaay back.... brace yourself... here they come:

http://img147.imageshack.us/img147/7797/r15c16predictaaf7.jpg

http://img147.imageshack.us/img147/5424/widthcontrolpredictamp8.jpg

73's de Edd

9/14/2006 6:13:48 PMDave Froehlich

Edd,
Thanks very much,

Dave
:It doesn't look like your referred R15 or C16 are either in the "width" circuitry, that is
:considering that they are in actuality THE Philco part number designations that might be
:silk screened on a PCB.Here are two thumbnails of both the IF circitry where those
:part designators are valid and used . As well the more probable thumbnail specifics
:of the hoz output section and the technique used for width regulation...e.g. the contrl of the
:screen grid supply voltage of the HOT.
:
:Stand waaaaaay back.... brace yourself... here they come:
:
:http://img147.imageshack.us/img147/7797/r15c16predictaaf7.jpg
:
:http://img147.imageshack.us/img147/5424/widthcontrolpredictamp8.jpg
:
:73's de Edd

9/14/2006 6:28:29 PMDave Froehlich

Edd,
The resistor is marked R15A and it does in fact connect to the width control. There is a .0002 mf C13 connected to it. Maybe the reference numbers on the PC board don't correspond to what they're referred to on the schematic or maybe things are so close, I don't see the number for this resistor. The PC board says 10L40 on it, and the chassis says 10L43 on it. Maybe there's a 10L40 schematic.
The terminal on the vertical linearity control broke off, so I have to replace it. This isn't the first time I replaced one of these. I forgot its value.
Anyway, maybe that disc capacitor is a little leaky.

Thanks,

9/15/2006 9:59:13 AMBill VA

Dave, 10L43 is covered by SAMS 466 folder 1. There is a PCB Sams 500 3. That's all I have. If you want a copy send your mail address to shedradios at yahoo.com and I will mail to you. You use, copy and send back. Or if you just need a page or two I will scan.

Bill VA

Edd,
: The resistor is marked R15A and it does in fact connect to the width control. There is a .0002 mf C13 connected to it. Maybe the reference numbers on the PC board don't correspond to what they're referred to on the schematic or maybe things are so close, I don't see the number for this resistor. The PC board says 10L40 on it, and the chassis says 10L43 on it. Maybe there's a 10L40 schematic.
: The terminal on the vertical linearity control broke off, so I have to replace it. This isn't the first time I replaced one of these. I forgot its value.
: Anyway, maybe that disc capacitor is a little leaky.
:
:Thanks,
:
:Dave
::It doesn't look like your referred R15 or C16 are either in the "width" circuitry, that is
::considering that they are in actuality THE Philco part number designations that might be
::silk screened on a PCB.Here are two thumbnails of both the IF circitry where those
::part designators are valid and used . As well the more probable thumbnail specifics
::of the hoz output section and the technique used for width regulation...e.g. the contrl of the
::screen grid supply voltage of the HOT.
::
::Stand waaaaaay back.... brace yourself... here they come:
::
::http://img147.imageshack.us/img147/7797/r15c16predictaaf7.jpg
::
::http://img147.imageshack.us/img147/5424/widthcontrolpredictamp8.jpg
::
::73's de Edd

9/15/2006 9:32:18 PMDave Froehlich

Bill,
I now have a copy of that SAMS folder. What do you think I should check to see why so much current is being pulled through that resistor?

Thanks,

Dave
:Dave, 10L43 is covered by SAMS 466 folder 1. There is a PCB Sams 500 3. That's all I have. If you want a copy send your mail address to shedradios at yahoo.com and I will mail to you. You use, copy and send back. Or if you just need a page or two I will scan.
:
:Bill VA
:
:Edd,
:: The resistor is marked R15A and it does in fact connect to the width control. There is a .0002 mf C13 connected to it. Maybe the reference numbers on the PC board don't correspond to what they're referred to on the schematic or maybe things are so close, I don't see the number for this resistor. The PC board says 10L40 on it, and the chassis says 10L43 on it. Maybe there's a 10L40 schematic.
:: The terminal on the vertical linearity control broke off, so I have to replace it. This isn't the first time I replaced one of these. I forgot its value.
:: Anyway, maybe that disc capacitor is a little leaky.
::
::Thanks,
::
::Dave
:::It doesn't look like your referred R15 or C16 are either in the "width" circuitry, that is
:::considering that they are in actuality THE Philco part number designations that might be
:::silk screened on a PCB.Here are two thumbnails of both the IF circitry where those
:::part designators are valid and used . As well the more probable thumbnail specifics
:::of the hoz output section and the technique used for width regulation...e.g. the contrl of the
:::screen grid supply voltage of the HOT.
:::
:::Stand waaaaaay back.... brace yourself... here they come:
:::
:::http://img147.imageshack.us/img147/7797/r15c16predictaaf7.jpg
:::
:::http://img147.imageshack.us/img147/5424/widthcontrolpredictamp8.jpg
:::
:::73's de Edd

9/16/2006 6:09:23 AMEdd

::Edd,
::: The resistor is marked R15A and it does in fact connect to the width control. There is a .0002 mf C13 connected to it. Maybe the reference numbers on the PC board don't correspond to what they're referred to on the schematic or maybe things are so close, I don't see the number for this resistor. The PC board says 10L40 on it, and the chassis says 10L43 on it. Maybe there's a 10L40 schematic.
::: The terminal on the vertical linearity control broke off, so I have to replace it. This isn't the first time I replaced one of these. I forgot its value.
::: Anyway, maybe that disc capacitor is a little leaky.
:::
:::Thanks,
:::
:::Dave

That # which Bill gave you was the complete Sams that I sent you , from which the thumbnails were excerpted.

Excess current thru that resistor ?

Thoughts / posssibilities:

Leakage in the screen bypass condenser as mentioned, float the ground side of the cap and then DC Voltage meter to ground reference to see if there is any voltage leakage....of consequense.

Seems like the width control is a wirewound unit, possibly time and heat has caused a breakdown of the
voluminous internal spiraled fine nichrome wire thru its encircling insulative media and has developed a leakage path to ground within the control.

Gassy horizontal output tube

Tube socket has broken down with a burnt carbon trail leading to ground at the screen grid pin.

Open the B+ supply line feeding the hot resistor and insert a series milliameter for monitoring and then start disconnecting loads downstream past that resistor to zero in on the culprit(s).

73's de Edd

9/16/2006 11:41:16 AMBill VA

Thanks Edd. Yes Dave, I'm looking at the same schematic as Edd's. I don't see where you mentioned the value of the resistor in question. You can't have a 1000 ohm resistor connected to the width control? Edd's info is good to go of course, I would first check some voltage readings, start with either side of "that" resistor.

Bill VA

:
:::Edd,
:::: The resistor is marked R15A and it does in fact connect to the width control. There is a .0002 mf C13 connected to it. Maybe the reference numbers on the PC board don't correspond to what they're referred to on the schematic or maybe things are so close, I don't see the number for this resistor. The PC board says 10L40 on it, and the chassis says 10L43 on it. Maybe there's a 10L40 schematic.
:::: The terminal on the vertical linearity control broke off, so I have to replace it. This isn't the first time I replaced one of these. I forgot its value.
:::: Anyway, maybe that disc capacitor is a little leaky.
::::
::::Thanks,
::::
::::Dave
:
:
:
:That # which Bill gave you was the complete Sams that I sent you , from which the thumbnails were excerpted.
:
:Excess current thru that resistor ?
:
:Thoughts / posssibilities:
:
:Leakage in the screen bypass condenser as mentioned, float the ground side of the cap and then DC Voltage meter to ground reference to see if there is any voltage leakage....of consequense.
:
:Seems like the width control is a wirewound unit, possibly time and heat has caused a breakdown of the
:voluminous internal spiraled fine nichrome wire thru its encircling insulative media and has developed a leakage path to ground within the control.
:
:Gassy horizontal output tube
:
:Tube socket has broken down with a burnt carbon trail leading to ground at the screen grid pin.
:
:Open the B+ supply line feeding the hot resistor and insert a series milliameter for monitoring and then start disconnecting loads downstream past that resistor to zero in on the culprit(s).
:
:73's de Edd