Re: HP8568B Error Correction Routine failure
It does :-(
CF 20 MHz
SPAN 100 kHz
RBW 1 kHz
VBW 1 kHz
REF LEVEL -10dBm
ATTEN 10 dB --> Peak at -10.60 dBm
ATTEN 20 dB --> Peak at - 7.70 dBm(out screen)
ATTEN 30 dB --> Peak at - 7.00 dBm(out screen)
ATTEN 40 dB --> Peak at -10.90 dBm
ATTEN 50 dB --> Peak at -10.90 dBm
ATTEN 60 dB --> Peak at - 7.70 dBm(out screen)
ATTEN 70 dB --> Peak at - 7.70 dBm(out screen)
Can I do anything to fix the problem ? Because the error is small, it really sounds to me like an IF gain problem rather than a bad attenuator element. I would try to go through the IF calibration procedure in the display section service manual, and look for signs of the problem there. For instance, assume the 8568's attenuator has 10, 20, and 30 dB sections. (I'm not sure what they actually are, offhand.) For RF ATTEN settings that require a 20-dB pad to be switched in, a corresponding 20-dB amplifier stage has to be enabled to keep the reference level constant. If the gain of that stage is a couple dB off, that would explain what you're seeing. Ideally you could rule out the RF attenuator by observing the amplitude at the input to the IF section with another receiver or analyzer as you go through the 10 dB steps. (Another way to do that is to substitute the output of a calibrated signal generator for the RF section's IF output.) -- john, KE5FX
|
I may not be much help -- my 182T might be different than the 182C you have.
In mine, the tube has three pins/wires coming out of the bottom; they are the vertical deflection and mesh (focus) pins and go to a board below the tube. The two vertical wires go to a gray cable and down to the plug in board in the rear.
Two pins coming from the top have wires going to the horizontal deflection amp on the right side (looking at the front). When the beam is centered, those two have zero volts between them, when the beam is on the side they are about 48 Volts.
Three pins coming out the side are the flood (graticule illuminator), not related to your problem. They also go to the board below the tube.
There are two compensation circuits, trace align and y-align that go to metal rings around the tube. If either of those circuits were not working (especially the trace align) you might have a problem. They don't use the vertical plates, they are magnetic coils.
By the way, you can get a horizontal line (rather than just a dot) by injecting a signal of 100 to 500 Hz or so into the external input. That might help.
The only other thing I can think of is that something magnetic (or accidentally magnetized) is near your unit. It would have to be really strong, though!
Erich
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--- In hp_agilent_equipment@..., francesco messineo <francesco.messineo@...> wrote:
Hello Erich,
first of all thanks for the answer!
On 9/27/09, erich_schlecht <schlechtca@...> wrote:
Frank,
These things often have several to many bad resistors in the high-voltage
sections, which includes the deflection amplifiers, focusing and intensity
section and power supplies.
yes, it happened on some other scopes, but I did check all the
high-voltage resistors and they seem in the correct tolerance range.
Also focus, cathode, grid voltages look normal.
You may have tried this, but it sounds like the signals are feeding back
through the power supplies, maybe the 100 volt? Have you checked these
voltages, especially while adjusting the controls that cause the symptoms. I
would start with the horizontal control causing a curved trace. Check the
voltages on the power supplies as you move the control. Also see if the
vertical plate voltages change as you rotate the horizontal control.
All low voltage supply are dead stable while I move all controls.
I checked also the vertical plate voltage with no plugin on the
connections on the lateral slide of the mainframe (green and white
wires). They always both remain at 0V no matter how I set controls. Of
course when connecting the multimeter probe to those contacts I see a
little vertical deflection due to noise coupled with the plates.
Distortion is always there.
I'm not saying it's not the CRT, just that it doesn't really sound like it
to me, and it's worth trying the other cheap things first. I really whish it isn't the CRT, that's probably the only thing not
worth fixing in a mainframe like this :/
Thanks again, I guess I need more hints now. I don't really know where
to poke around looking for electronic faults.
Frank IZ8DWF
|
Re: HP8568B Error Correction Routine failure
--- In hp_agilent_equipment@..., "John Miles" <jmiles@...> wrote:
Try putting the calibrator onscreen (CF 20 MHz, SPAN 100 kHz, REF LEVEL -10
dBm) and hitting the up and down arrows to step the RF ATTEN setting from 10
to 70 dB. The calibrator's amplitude shouldn't vary more than a dB at any
point. If it does, then that is probably what's causing the self-cal to
fail.
It does :-( CF 20 MHz SPAN 100 kHz RBW 1 kHz VBW 1 kHz REF LEVEL -10dBm ATTEN 10 dB --> Peak at -10.60 dBm ATTEN 20 dB --> Peak at - 7.70 dBm(out screen) ATTEN 30 dB --> Peak at - 7.00 dBm(out screen) ATTEN 40 dB --> Peak at -10.90 dBm ATTEN 50 dB --> Peak at -10.90 dBm ATTEN 60 dB --> Peak at - 7.70 dBm(out screen) ATTEN 70 dB --> Peak at - 7.70 dBm(out screen) Can I do anything to fix the problem ? Art IK7JWY
|
Re: HP8568B Error Correction Routine failure
No, it doesn't have anything to do with the 2nd LO. There's a
gain-adjustment stage that isn't responding properly somewhere -- either in
the IF amp section, or in the RF attenuator itself.
Try putting the calibrator onscreen (CF 20 MHz, SPAN 100 kHz, REF LEVEL -10
dBm) and hitting the up and down arrows to step the RF ATTEN setting from 10
to 70 dB. The calibrator's amplitude shouldn't vary more than a dB at any
point. If it does, then that is probably what's causing the self-cal to
fail. If it remains steady at all RF attenuator settings, look for the
problem in the IF gain-step control circuits in the display section.
-- john, KE5FX
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-----Original Message-----
From: hp_agilent_equipment@...
[mailto:hp_agilent_equipment@...]On Behalf Of Jim Popwell Jr
Sent: Sunday, September 27, 2009 12:06 PM
To: hp_agilent_equipment@...
Subject: Re: [hp_agilent_equipment] HP8568B Error Correction Routine
failure
it looks as if the analyzer is telling you to adjust the 2nd local
oscillator amplitude down a little to bring it into a range where the
autocal routine can handle it... check the 2nd lo cal section in your
manual
jim
On Sep 27, 2009, at 11:46 AM, ik7jwy wrote:
HI,
yesterday I discovered this trouble on my HP8568B spectrum analyzer.
When I put ON the S.A. everything works fine , the two red leds
INSTR CHECK light for a while, then come back OFF. No error message
on the display.
I perform the two routines RECALL REG 8 and RECALL REG 9 and
everything continues to sounds good.
But, when I go to the Error Correction Routine (SHIFT+W) then I see
the failure. At the end of the routine I see on the display this
message "ADJUST AMPTD CAL", instead of "COOR'D", and all the
parameters (RBW, REF Level and so on) don't come back to the Preset.
You can see here what happens:
If I start again the routine, at the end I get the same result.
Any idea ? Thanks.
Art IK7JWY
|
Re: HP8568B Error Correction Routine failure
it looks as if the analyzer is telling you to adjust the 2nd local
oscillator amplitude down a little to bring it into a range where the
autocal routine can handle it... check the 2nd lo cal section in your
manual
jim
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Show quoted text
On Sep 27, 2009, at 11:46 AM, ik7jwy wrote: HI,
yesterday I discovered this trouble on my HP8568B spectrum analyzer.
When I put ON the S.A. everything works fine , the two red leds
INSTR CHECK light for a while, then come back OFF. No error message
on the display.
I perform the two routines RECALL REG 8 and RECALL REG 9 and
everything continues to sounds good.
But, when I go to the Error Correction Routine (SHIFT+W) then I see
the failure. At the end of the routine I see on the display this
message "ADJUST AMPTD CAL", instead of "COOR'D", and all the
parameters (RBW, REF Level and so on) don't come back to the Preset.
You can see here what happens:
If I start again the routine, at the end I get the same result.
Any idea ? Thanks.
Art IK7JWY
|
HP8568B Error Correction Routine failure
HI,
yesterday I discovered this trouble on my HP8568B spectrum analyzer. When I put ON the S.A. everything works fine , the two red leds INSTR CHECK light for a while, then come back OFF. No error message on the display.
I perform the two routines RECALL REG 8 and RECALL REG 9 and everything continues to sounds good.
But, when I go to the Error Correction Routine (SHIFT+W) then I see the failure. At the end of the routine I see on the display this message "ADJUST AMPTD CAL", instead of "COOR'D", and all the parameters (RBW, REF Level and so on) don't come back to the Preset.
You can see here what happens:
If I start again the routine, at the end I get the same result.
Any idea ? Thanks.
Art IK7JWY
|
NOISE FIGURE TEST HP 8971C ........
Hello everybody,
HP 8971B Re: who could give me the features (GAIN and N / F) of the IF amplifier 10-700 Mhz Avantek SCB4-2837??
Thank you for your responses.
73's : Ren¨¦ F6BKB.
|
Hello Erich, first of all thanks for the answer! On 9/27/09, erich_schlecht <schlechtca@...> wrote: Frank,
These things often have several to many bad resistors in the high-voltage
sections, which includes the deflection amplifiers, focusing and intensity
section and power supplies.
yes, it happened on some other scopes, but I did check all the high-voltage resistors and they seem in the correct tolerance range. Also focus, cathode, grid voltages look normal. You may have tried this, but it sounds like the signals are feeding back
through the power supplies, maybe the 100 volt? Have you checked these
voltages, especially while adjusting the controls that cause the symptoms. I
would start with the horizontal control causing a curved trace. Check the
voltages on the power supplies as you move the control. Also see if the
vertical plate voltages change as you rotate the horizontal control.
All low voltage supply are dead stable while I move all controls. I checked also the vertical plate voltage with no plugin on the connections on the lateral slide of the mainframe (green and white wires). They always both remain at 0V no matter how I set controls. Of course when connecting the multimeter probe to those contacts I see a little vertical deflection due to noise coupled with the plates. Distortion is always there. I'm not saying it's not the CRT, just that it doesn't really sound like it
to me, and it's worth trying the other cheap things first. I really whish it isn't the CRT, that's probably the only thing not worth fixing in a mainframe like this :/ Thanks again, I guess I need more hints now. I don't really know where to poke around looking for electronic faults. Frank IZ8DWF
|
Frank,
These things often have several to many bad resistors in the high-voltage sections, which includes the deflection amplifiers, focusing and intensity section and power supplies.
You may have tried this, but it sounds like the signals are feeding back through the power supplies, maybe the 100 volt? Have you checked these voltages, especially while adjusting the controls that cause the symptoms. I would start with the horizontal control causing a curved trace. Check the voltages on the power supplies as you move the control. Also see if the vertical plate voltages change as you rotate the horizontal control.
I'm not saying it's not the CRT, just that it doesn't really sound like it to me, and it's worth trying the other cheap things first.
Erich
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Show quoted text
--- In hp_agilent_equipment@..., francesco messineo <francesco.messineo@...> wrote:
Hi all,
just an update, I found an open resistor on the gate amplifier board,
A7R28, it's in the path to the control grid.
After replacing it I have a spot, rather large and almost can't be
focused correctly.
Now intensity kind of works, but moves the spot with varying intensity.
Also horizontal position works, but the spot moves on a curved path
and focusing varies through the path.
The more I think about it the more I suspect a bad CRT.
As always any hint is welcome.
best regards
Frank
|
FS: GPIB cables, TM5006 RackMount, Tektronix K420 cart
I have been consolidating the shop and have the following available.
GPIB Cables (all were installed and working until I disassembled a rack
today.
(1) HP9220R 12" GPIB $7.50
(2) HP108331 48" GPIB $12.00, each
TM5006 Rack Mount $45.00 (I was using this unit until 1 week ago, when I
sold the modules in the rack)
Tektronix K420 equipment cart with straps $75
All prices are based on pickup in Alameda, California. Shipping at cost
(including packing, if required). K420 will not be shipped and is only
available for pick-up.
email me off list if you want any of these items.
|
545xx scope fails time null cal
I was running through the cal procedure for a 54522A and it completes everything with a pass except for the time null cal on "chan 1 & ext" with a code of 0000 0000 0001 0001. Does anyone know what this code means, or if this is something that is practical repair ? I posted a similar inquiry on the Agilent scope forum but so far no comments. Thanks for any tips.
AW
|
--- In hp_agilent_equipment@..., "m8jpk" <ttesenq@...> wrote:
Hello Folks
I am trying to Source the following HP Parts
Any Advice or Offers most appreciated.
1826-0195
1820-1252
1820-0944
Thanks M8JPK
The 1820-0944 is a CD4025 The 1820-1252 is a LD110CJ The 1826-0195 is a LD111CJ The CD4025 is easy enough to find; but the LD110 and LD111 are going to be really, really hard to find. They weren't in production all that long, and were hard to find even while the were being produced. Best bet on those two is to find a donor multimeter somewhere and salvage them. Cheers!! Dave M
|
Hello Folks
I am trying to Source the following HP Parts
Any Advice or Offers most appreciated.
1826-0195
1820-1252
1820-0944
Thanks M8JPK
|
Hi all,
just an update, I found an open resistor on the gate amplifier board,
A7R28, it's in the path to the control grid.
After replacing it I have a spot, rather large and almost can't be
focused correctly.
Now intensity kind of works, but moves the spot with varying intensity.
Also horizontal position works, but the spot moves on a curved path
and focusing varies through the path.
The more I think about it the more I suspect a bad CRT.
As always any hint is welcome.
best regards
Frank
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Show quoted text
On 9/26/09, francesco messineo <francesco.messineo@...> wrote: Hi Ken,
thanks for the answer, my findings after your test follow
On 9/26/09, ken chalfant <kpchalfant@...> wrote:
Greetings Frank,
Please advise as to the plug-ins you have in the main frame. for now, no plugins installed, until at least I can see something on
the CRT. The other mainframe shows a spot even with no plugins if I
set to ext display.
I can't remember for certain - the 182C is not storage - correct?
right, it's not storage.
What happens when you depress the "BEAM FINDER"?
nothing happens.
What happens when you depress the "BEAM FINDER" and move both the X and Y
position knobs?
nothing seen, with no plugins I have only the horizontal knob anyway.
Please turn the intensity up to very bright - just once - and power the
unit
OFF. Does the off screen dot move toward the center of the CRT before it
fades away?
no, and probably it's not an off screen dot since I can see it only
when turning the scale illumination knob, not the intensity.
However if I have the intensity up and I power on the mainframe I see
a fast spot moving and disappearing in less than one second.
Maybe a problem on the intensity circuitry?
Let's see if we can figure out why it does not want to behave.
I hope so :-)
Warm regards,
thanks a lot and best regards
Frank
Ken
----- Original Message -----
From: francesco messineo<mailto:francesco.messineo@...>
To: hp_agilent_equipment<mailto:hp_agilent_equipment@...>
Sent: Friday, September 25, 2009 2:55 PM
Subject: [hp_agilent_equipment] HP-182C repair
Hello all,
I'm trying to revive a 182C oscilloscope. I have the service manual,
but it's for a different serial group. I think it should be enough
close anyway.
So far I've checked and set all low voltages and the cathode voltage.
Then I tried to set the intensity limit but there's no visible spot on
the CRT (I checked on another working 182T and with the same controls
set there's a spot and can be moved with horizontal position).
It seems there's a spot just off screen around the lower right corner
of the CRT, however it doesn't move with horizontal control.
I checked the control grid and focus voltages and they seem to be ok,
also the grid voltage changes with the intensity limit trimmer.
On the first two times I powered the scope I heard crackling sounds
and seen some "lightning-like" tracks on the CRT, the next times it
didn't make any sound or firework on the screen.
Now I think I should start to troubleshoot vertical and horizontal
drivers, but the cracks and fireworks made me wonder about the CRT,
can it be damaged?
Please don't suggest me to swap the CRT with the working unit, I just
tried to remove the connections on the neck but they seem stuck and
I'm afraid I can damage the glass.
I'm seeking for hints and advices, if the CRT is likely damaged I'm
going to sell the old thing for spares and not spend more time with
it.
Thanks in advance and best regards
Frank IZ8DWF
|
Hi Ken, thanks for the answer, my findings after your test follow On 9/26/09, ken chalfant <kpchalfant@...> wrote: Greetings Frank,
Please advise as to the plug-ins you have in the main frame. for now, no plugins installed, until at least I can see something on the CRT. The other mainframe shows a spot even with no plugins if I set to ext display.
I can't remember for certain - the 182C is not storage - correct?
right, it's not storage.
What happens when you depress the "BEAM FINDER"?
nothing happens.
What happens when you depress the "BEAM FINDER" and move both the X and Y
position knobs?
nothing seen, with no plugins I have only the horizontal knob anyway.
Please turn the intensity up to very bright - just once - and power the unit
OFF. Does the off screen dot move toward the center of the CRT before it
fades away?
no, and probably it's not an off screen dot since I can see it only when turning the scale illumination knob, not the intensity. However if I have the intensity up and I power on the mainframe I see a fast spot moving and disappearing in less than one second. Maybe a problem on the intensity circuitry?
Let's see if we can figure out why it does not want to behave.
I hope so :-)
Warm regards,
thanks a lot and best regards Frank
Ken
----- Original Message -----
From: francesco messineo<mailto:francesco.messineo@...>
To: hp_agilent_equipment<mailto:hp_agilent_equipment@...>
Sent: Friday, September 25, 2009 2:55 PM
Subject: [hp_agilent_equipment] HP-182C repair
Hello all,
I'm trying to revive a 182C oscilloscope. I have the service manual,
but it's for a different serial group. I think it should be enough
close anyway.
So far I've checked and set all low voltages and the cathode voltage.
Then I tried to set the intensity limit but there's no visible spot on
the CRT (I checked on another working 182T and with the same controls
set there's a spot and can be moved with horizontal position).
It seems there's a spot just off screen around the lower right corner
of the CRT, however it doesn't move with horizontal control.
I checked the control grid and focus voltages and they seem to be ok,
also the grid voltage changes with the intensity limit trimmer.
On the first two times I powered the scope I heard crackling sounds
and seen some "lightning-like" tracks on the CRT, the next times it
didn't make any sound or firework on the screen.
Now I think I should start to troubleshoot vertical and horizontal
drivers, but the cracks and fireworks made me wonder about the CRT,
can it be damaged?
Please don't suggest me to swap the CRT with the working unit, I just
tried to remove the connections on the neck but they seem stuck and
I'm afraid I can damage the glass.
I'm seeking for hints and advices, if the CRT is likely damaged I'm
going to sell the old thing for spares and not spend more time with
it.
Thanks in advance and best regards
Frank IZ8DWF
|
Greetings Frank,
Please advise as to the plug-ins you have in the main frame.
I can't remember for certain - the 182C is not storage - correct?
What happens when you depress the "BEAM FINDER"?
What happens when you depress the "BEAM FINDER" and move both the X and Y position knobs?
Please turn the intensity up to very bright - just once - and power the unit OFF. Does the off screen dot move toward the center of the CRT before it fades away?
Let's see if we can figure out why it does not want to behave.
Warm regards,
Ken
toggle quoted message
Show quoted text
----- Original Message -----
From: francesco messineo<mailto:francesco.messineo@...>
To: hp_agilent_equipment<mailto:hp_agilent_equipment@...>
Sent: Friday, September 25, 2009 2:55 PM
Subject: [hp_agilent_equipment] HP-182C repair
Hello all,
I'm trying to revive a 182C oscilloscope. I have the service manual,
but it's for a different serial group. I think it should be enough
close anyway.
So far I've checked and set all low voltages and the cathode voltage.
Then I tried to set the intensity limit but there's no visible spot on
the CRT (I checked on another working 182T and with the same controls
set there's a spot and can be moved with horizontal position).
It seems there's a spot just off screen around the lower right corner
of the CRT, however it doesn't move with horizontal control.
I checked the control grid and focus voltages and they seem to be ok,
also the grid voltage changes with the intensity limit trimmer.
On the first two times I powered the scope I heard crackling sounds
and seen some "lightning-like" tracks on the CRT, the next times it
didn't make any sound or firework on the screen.
Now I think I should start to troubleshoot vertical and horizontal
drivers, but the cracks and fireworks made me wonder about the CRT,
can it be damaged?
Please don't suggest me to swap the CRT with the working unit, I just
tried to remove the connections on the neck but they seem stuck and
I'm afraid I can damage the glass.
I'm seeking for hints and advices, if the CRT is likely damaged I'm
going to sell the old thing for spares and not spend more time with
it.
Thanks in advance and best regards
Frank IZ8DWF
|
Re: Agilent E4420 series Sig Gen
Hello Paul,
Thanks for the reply....am looking at a 4420B, I know it only goes to 2Ghz; I wonder if also supports the the functions you mention....I guess it may depend on installed options....Got any idea about fair or going prices?
Thanks Again,
Steve
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Show quoted text
----- Original Message -----
From: Paul Read
To: 'hp_agilent_equipment@...'
Sent: Friday, September 25, 2009 8:45 AM
Subject: [hp_agilent_equipment] Re:Agilent E4420 series Sig Gen
Hi Steve,
I currently have an E4422b on my bench, and have found it to be very good. The unit I have has various modulation sources including a function generator, and the performance of that is excellent , I would certainly make room for one on my bench at home. It would replace at least 2 boxes there, so the XYL would be pleases :o)
The unit also includes sweeps of frequency and power.
Yum !
73
Paul
|
Re: Part needed for a HP 6227B Dual Power Supply
Tom,
Isn't it just a regular switch you can by from Mouser or Digikey? I have a 6228B that's similar, but I'll admit I haven't opened it up to look at the switches, though I probably should clean them. On a personal note, I hate slide switches.
Erich
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Show quoted text
--- In hp_agilent_equipment@..., "Tom Miller" <tmiller@...> wrote:
Greetings,
Does anyone have a parts hanger queen that can supply a switch. It is the
Volts/Amps slide switch, part number 3101-1288, a 3-pole - double throw
slide switch.
With fingers crossed,
Tom
[Non-text portions of this message have been removed]
|
Hewlett Packard 427A -- Complete insides less meter: Two PCB's, Range & Attenuator Switch assemblies, etc, mounted to metal framework -- $20
Hewlett Packard PCB Assemblies -- $10 each
00745-66512
00745-66513
00745-66514
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00745-66516
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00745-66544
00745-66551
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00745-66558
05326-20008 (less readouts)
05326-60002
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05326-60009
05326-60013
05327-60002
05327-60003
05327-60004
05327-60009
69330-60021
More test equipment is available on my webpage:
Also Test Equipment Manuals & some others at:
Contact: Marv WC6W 310 649 3111 (reasonable hours
Pacific Time please)
|
Hello all,
I'm trying to revive a 182C oscilloscope. I have the service manual,
but it's for a different serial group. I think it should be enough
close anyway.
So far I've checked and set all low voltages and the cathode voltage.
Then I tried to set the intensity limit but there's no visible spot on
the CRT (I checked on another working 182T and with the same controls
set there's a spot and can be moved with horizontal position).
It seems there's a spot just off screen around the lower right corner
of the CRT, however it doesn't move with horizontal control.
I checked the control grid and focus voltages and they seem to be ok,
also the grid voltage changes with the intensity limit trimmer.
On the first two times I powered the scope I heard crackling sounds
and seen some "lightning-like" tracks on the CRT, the next times it
didn't make any sound or firework on the screen.
Now I think I should start to troubleshoot vertical and horizontal
drivers, but the cracks and fireworks made me wonder about the CRT,
can it be damaged?
Please don't suggest me to swap the CRT with the working unit, I just
tried to remove the connections on the neck but they seem stuck and
I'm afraid I can damage the glass.
I'm seeking for hints and advices, if the CRT is likely damaged I'm
going to sell the old thing for spares and not spend more time with
it.
Thanks in advance and best regards
Frank IZ8DWF
|
