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Old September 4th 04, 01:55 PM
Timoleon
 
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Default Paging Frank Cattell Yaesu FRG-8800

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Hi Frank (and anyone else reading!) ---

A couple of years ago you suggested a solution for a problem I was
having with my FRG-8800. The display locks up and starts blinking after
about 15 minutes of use. I think the PLL is becoming unlocked, but I'm
just guessing.

Do you remember what the problem might be, and what the solution is?

Thanks!

Tim
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Old September 4th 04, 02:36 PM
John Crabtree
 
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Timoleon, , on 9/4/04 wrote:

Hi Frank (and anyone else reading!) ---

A couple of years ago you suggested a solution for a problem I was
having with my FRG-8800. The display locks up and starts blinking after
about 15 minutes of use. I think the PLL is becoming unlocked, but I'm
just guessing.

Do you remember what the problem might be, and what the solution is?

Thanks!

Tim


I exchanged emails with Frank on this subject a few weeks ago. He advised me
that the problem is with one of the slug tuned coils which drifts, and that the
adjustment is covered in the service manual.

The adjustment to which he was referring is on page 38 of the service manual,
and relates to the 2nd PLL unit. After allowing the radio to warm up for 30
minutes, set the radio to 10.000MHz and adjust T2007 (T07 on cct diagram) to
give a voltage of 5.0 volts at TP2003 (TP3 on the cct diagram). Then set the
radio to 29.999MHz and check for 2.0 to 3.2 volts at TP2003

The PLL board is on the top of the radio when you remove the cover. Looking
down, with the bottom of the radio in front of you, Go roughly one third of
the way across the board from left to right, and one third of the way up the
board from bottom to top, and you will be on a smaller screening box. Inductor
T07 is towards the lower edge of the box. TP3 is just below the lower left
hand corner of the box, and IIRC is marked on the PCB.

Please note that I have not made this adjustment. I was looking at the radio
of a friend of a friend. We measured a voltage of ca 0.98 volts at TP3 when it
should have been 5.0 volts. Despite a huge number of tuning tools we did not
have one to fit the slug. We decided to postpone our efforts until later in
the year.

HTH and 73

John KC0GGH
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Old September 4th 04, 03:40 PM
Timoleon
 
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John Crabtree wrote:
| Timoleon, , on 9/4/04 wrote:
|
|
|Hi Frank (and anyone else reading!) ---
|
|A couple of years ago you suggested a solution for a problem I was
|having with my FRG-8800. The display locks up and starts blinking after
|about 15 minutes of use. I think the PLL is becoming unlocked, but I'm
|just guessing.
|
|Do you remember what the problem might be, and what the solution is?
|
|Thanks!
|
|Tim
|
|
| I exchanged emails with Frank on this subject a few weeks ago. He
advised me
| that the problem is with one of the slug tuned coils which drifts, and
that the
| adjustment is covered in the service manual.
|
| The adjustment to which he was referring is on page 38 of the service
manual,
| and relates to the 2nd PLL unit. After allowing the radio to warm up
for 30
| minutes, set the radio to 10.000MHz and adjust T2007 (T07 on cct
diagram) to
| give a voltage of 5.0 volts at TP2003 (TP3 on the cct diagram). Then
set the
| radio to 29.999MHz and check for 2.0 to 3.2 volts at TP2003
|
| The PLL board is on the top of the radio when you remove the cover.
Looking
| down, with the bottom of the radio in front of you, Go roughly one
third of
| the way across the board from left to right, and one third of the way
up the
| board from bottom to top, and you will be on a smaller screening box.
Inductor
| T07 is towards the lower edge of the box. TP3 is just below the lower
left
| hand corner of the box, and IIRC is marked on the PCB.
|
| Please note that I have not made this adjustment. I was looking at
the radio
| of a friend of a friend. We measured a voltage of ca 0.98 volts at
TP3 when it
| should have been 5.0 volts. Despite a huge number of tuning tools we
did not
| have one to fit the slug. We decided to postpone our efforts until
later in
| the year.
|
| HTH and 73
|
| John KC0GGH


Thanks, John, for your answer! Although the expertise required to fix
the matter seems a little daunting --- visions of my fried body on the
floor of my shack and all... How much of a chance to I have of becoming
a pork chop by attempting the fix?

I think I'll print your post out and take it to my electrician friend!

Tim
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