I have discovered where someone placed a 2 small signal diodes (like a 1N914) in the scope. One is across a 1K ohm resistor (R58). The other is alone on a terminal. Wouldn't this cause a problem. It's not on the schematic. I have yet to find what circuit the other small signal diode is in. There are no such small signal diodes in the schematic anywhere. Maybe someone was trying to compensate for bad filter capacitors. I think I may have found a problem.Have I? Should I cut out that diode?
Schematics are here: http://www.thevalvepage.com/servdata/testeq/tektronx.htm
This circuit is in:
545_2.pdf on Page 24 of the pdf file.
The second diode is connected to a "Lockout Level" control. Here's what I see when I trace it out.One end of the Lockout level control is connected to -150 v. The wiper is connected to a 470 K ohm resistor which is in series with a 270K resistor which has a small capacitor in parallel with it. This is then connected to this small signal diode + end. There is also a 68K ohm resistor connected to the same diode + end. The other end of the 68K ohm resistor is connected to the 100 V line. THe other end of the lock out level control is connected through a 100K ohm resistor to the chassis.
What did someone do here? Should I remove these diodes that look like they don't belong in this scope?
Thanks,
Dave
I forgot to say that the other end of the small signal diode is connected to the chassis. I really don't see what this is supposed to do. Maybe someone knows.
Thanks,
Dave
:Hello All,
: I have discovered where someone placed a 2 small signal diodes (like a 1N914) in the scope. One is across a 1K ohm resistor (R58). The other is alone on a terminal. Wouldn't this cause a problem. It's not on the schematic. I have yet to find what circuit the other small signal diode is in. There are no such small signal diodes in the schematic anywhere. Maybe someone was trying to compensate for bad filter capacitors. I think I may have found a problem.Have I? Should I cut out that diode?
:
:Schematics are here: http://www.thevalvepage.com/servdata/testeq/tektronx.htm
:
:This circuit is in:
:
: 545_2.pdf on Page 24 of the pdf file.
:
:The second diode is connected to a "Lockout Level" control. Here's what I see when I trace it out.One end of the Lockout level control is connected to -150 v. The wiper is connected to a 470 K ohm resistor which is in series with a 270K resistor which has a small capacitor in parallel with it. This is then connected to this small signal diode + end. There is also a 68K ohm resistor connected to the same diode + end. The other end of the 68K ohm resistor is connected to the 100 V line. THe other end of the lock out level control is connected through a 100K ohm resistor to the chassis.
:
: What did someone do here? Should I remove these diodes that look like they don't belong in this scope?
:
:Thanks,
:
:Dave
:
I found these diodes in the 545A schematic. This was modified sometime in the near past. I'll accept it as correct and move on.
Thanks,
Dave
:Hello Again All,
: I forgot to say that the other end of the small signal diode is connected to the chassis. I really don't see what this is supposed to do. Maybe someone knows.
:
:Thanks,
:
:Dave
:
::Hello All,
:: I have discovered where someone placed a 2 small signal diodes (like a 1N914) in the scope. One is across a 1K ohm resistor (R58). The other is alone on a terminal. Wouldn't this cause a problem. It's not on the schematic. I have yet to find what circuit the other small signal diode is in. There are no such small signal diodes in the schematic anywhere. Maybe someone was trying to compensate for bad filter capacitors. I think I may have found a problem.Have I? Should I cut out that diode?
::
::Schematics are here: http://www.thevalvepage.com/servdata/testeq/tektronx.htm
::
::This circuit is in:
::
:: 545_2.pdf on Page 24 of the pdf file.
::
::The second diode is connected to a "Lockout Level" control. Here's what I see when I trace it out.One end of the Lockout level control is connected to -150 v. The wiper is connected to a 470 K ohm resistor which is in series with a 270K resistor which has a small capacitor in parallel with it. This is then connected to this small signal diode + end. There is also a 68K ohm resistor connected to the same diode + end. The other end of the 68K ohm resistor is connected to the 100 V line. THe other end of the lock out level control is connected through a 100K ohm resistor to the chassis.
::
:: What did someone do here? Should I remove these diodes that look like they don't belong in this scope?
::
::Thanks,
::
::Dave
::
:
Your relevant 1N914 situation sounds like a pimple on an elephants glutamus maximus . .in the total scheme
|
:Hello Again Again,
: I found these diodes in the 545A schematic. This was modified sometime in the near past. I'll accept it as correct and move on.
:
:Thanks,
:
:Dave
::Hello Again All,
:: I forgot to say that the other end of the small signal diode is connected to the chassis. I really don't see what this is supposed to do. Maybe someone knows.
::
::Thanks,
::
::Dave
::
:::Hello All,
::: I have discovered where someone placed a 2 small signal diodes (like a 1N914) in the scope. One is across a 1K ohm resistor (R58). The other is alone on a terminal. Wouldn't this cause a problem. It's not on the schematic. I have yet to find what circuit the other small signal diode is in. There are no such small signal diodes in the schematic anywhere. Maybe someone was trying to compensate for bad filter capacitors. I think I may have found a problem.Have I? Should I cut out that diode?
:::
:::Schematics are here: http://www.thevalvepage.com/servdata/testeq/tektronx.htm
:::
:::This circuit is in:
:::
::: 545_2.pdf on Page 24 of the pdf file.
:::
:::The second diode is connected to a "Lockout Level" control. Here's what I see when I trace it out.One end of the Lockout level control is connected to -150 v. The wiper is connected to a 470 K ohm resistor which is in series with a 270K resistor which has a small capacitor in parallel with it. This is then connected to this small signal diode + end. There is also a 68K ohm resistor connected to the same diode + end. The other end of the 68K ohm resistor is connected to the 100 V line. THe other end of the lock out level control is connected through a 100K ohm resistor to the chassis.
:::
::: What did someone do here? Should I remove these diodes that look like they don't belong in this scope?
:::
:::Thanks,
:::
:::Dave
:::
::
:
I'll take the measurements and let you know the numbers later today.
Thanks,
Dave
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:Sir David . . . . .
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:Your relevant 1N914 situation sounds like a pimple on an elephants glutamus maximus . .in the total scheme
:of situations.
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:Whut about the last heard serious condition of the units minus 150 supply being at ~ minus 170 VDC ?
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:Will the unit accept the CA plug in, being in circuit now, is the hot resistor still
: " SMOKIN' " , is the HOZ trace positoning situation still the same ?
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: . . . . . . 73's de Edd
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::Hello Again Again,
:: I found these diodes in the 545A schematic. This was modified sometime in the near past. I'll accept it as correct and move on.
::
::Thanks,
::
::Dave
:::Hello Again All,
::: I forgot to say that the other end of the small signal diode is connected to the chassis. I really don't see what this is supposed to do. Maybe someone knows.
:::
:::Thanks,
:::
:::Dave
:::
::::Hello All,
:::: I have discovered where someone placed a 2 small signal diodes (like a 1N914) in the scope. One is across a 1K ohm resistor (R58). The other is alone on a terminal. Wouldn't this cause a problem. It's not on the schematic. I have yet to find what circuit the other small signal diode is in. There are no such small signal diodes in the schematic anywhere. Maybe someone was trying to compensate for bad filter capacitors. I think I may have found a problem.Have I? Should I cut out that diode?
::::
::::Schematics are here: http://www.thevalvepage.com/servdata/testeq/tektronx.htm
::::
::::This circuit is in:
::::
:::: 545_2.pdf on Page 24 of the pdf file.
::::
::::The second diode is connected to a "Lockout Level" control. Here's what I see when I trace it out.One end of the Lockout level control is connected to -150 v. The wiper is connected to a 470 K ohm resistor which is in series with a 270K resistor which has a small capacitor in parallel with it. This is then connected to this small signal diode + end. There is also a 68K ohm resistor connected to the same diode + end. The other end of the 68K ohm resistor is connected to the 100 V line. THe other end of the lock out level control is connected through a 100K ohm resistor to the chassis.
::::
:::: What did someone do here? Should I remove these diodes that look like they don't belong in this scope?
::::
::::Thanks,
::::
::::Dave
::::
:::
::
: