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I followed what you did, until here...

I need some help - er, understanding...

"A few off on the 27MHz we were at 24MHz" - how did you determine that?

With L15 you just follow the voltages on TP2 - the radio tries to lock in on that looking thru Pin 9 and the "gating" results on Pins 7,6 and 5 (Pump Charge) through C101 and C102. Both caps are tied, being used as a gated loop with the internal divisor the PLL uses. Channel 1's voltage on TP2 should be low, about 1 volt or so, while channel 40 pushes the Varactor voltage to about 4V.
If the PLL is alive, but L15 is not ringing, TP2 shows a "ramp" steep rise slow fall - trying to make the Varactor ring with L15 - checking it thru TR11's output sent back into PLL's Pin 9.
Best to tune L16 to maximize RX IF for image at this stage of repair.
Then Retune L16 during final tuneup to equalize performance of RX and TX
The Varactor D11, a 1SV63 is about 22~26pF at 1 volt can be as low as 6pF when it tries to lock on 40 - this voltage pulls at the junction layer, making this gap smaller - lessening the capacitance - raising the resonate frequency combined with L15's inductive behavior. Going to channel 40 changes (lessens) D11's varactor capacitance Pushes up the resonate ring frequency Pin 9 sees from the output of TR11

TR12 just buffer amps the TR11 results and shoots it two ways, one to TP3 the other to IC2 - thru L16
- so L15 is your CRITICAL component. You have to get it ringing to even push a signal into TR12 and L16.
- so if you're not getting anything at TP3 - a new Crystal Filter is just going to sit there - just like it's predecessor
- so don't throw too much into the radio for the parts you may need to fix it are more important right now to make it work.

<blockquote data-quote="Handy Andy" data-source="post: 765974" data-attributes="member: 52309">I followed what you did, until here...I need some help - er, understanding...&quot;A few off on the 27MHz we were at 24MHz&quot; - how did you determine that?
With L15 you just follow the voltages on TP2 - the radio tries to lock in on that looking thru Pin 9 and the &quot;gating&quot; results on Pins&nbsp; 7,6 and 5 (Pump Charge) through C101 and C102. Both caps are tied, being used as a gated loop with the internal divisor the PLL uses. Channel 1&#039;s voltage on TP2 should be low, about 1 volt or so, while channel 40 pushes the Varactor voltage to about 4V.<ul>
<li data-xf-list-type="ul">If the PLL is alive, but L15 is not ringing, TP2 shows a &quot;ramp&quot; steep rise slow fall - trying to make the Varactor ring with L15 - checking it thru TR11&#039;s output sent back into PLL&#039;s Pin 9.</li>
<li data-xf-list-type="ul">Best to tune L16 to maximize RX IF for image at this stage of repair. </li>
<li data-xf-list-type="ul">Then Retune L16 during final tuneup to equalize performance of RX and TX</li>
</ul>The Varactor D11, a 1SV63 is about 22~26pF at 1 volt can be as low as 6pF when it tries to lock on 40 - this voltage pulls at the junction layer, making this gap smaller - lessening the capacitance - raising the resonate frequency combined with L15&#039;s inductive behavior. Going to channel 40 changes (lessens) D11&#039;s varactor capacitance Pushes up the resonate ring frequency Pin 9 sees from the output of TR11TR12 just buffer amps the TR11 results and shoots it two ways, one to TP3 the other to IC2 - thru L16 <ul>
<li data-xf-list-type="ul">- so L15 is your CRITICAL component. You have to get it ringing to even push a signal into TR12 and L16.</li>
<li data-xf-list-type="ul">- so if you&#039;re not getting anything at TP3 - a new Crystal Filter is just going to sit there - just like it&#039;s predecessor <ul>
<li data-xf-list-type="ul">- so don&#039;t throw too much into the radio for the parts you may need to fix it are more important right now to make it work.</li>
</ul></li>
</ul></blockquote>

[QUOTE="Handy Andy, post: 765974, member: 52309"] I followed what you did, until here... I need some help - er, understanding... [INDENT][INDENT]"[I]A few off on the 27MHz we were at 24MHz[/I]" - how did you determine that?[/INDENT][/INDENT] With L15 you just follow the voltages on TP2 - the radio tries to lock in on that looking thru Pin 9 and the "gating" results on Pins 7,6 and 5 (Pump Charge) through C101 and C102. Both caps are tied, being used as a gated loop with the internal divisor the PLL uses. Channel 1's voltage on TP2 should be low, about 1 volt or so, while channel 40 pushes the Varactor voltage to about 4V. [LIST] [*]If the PLL is alive, but L15 is not ringing, TP2 shows a "ramp" steep rise slow fall - trying to make the Varactor ring with L15 - checking it thru TR11's output sent back into PLL's Pin 9. [*]Best to tune L16 to maximize RX IF for image at this stage of repair. [*]Then Retune L16 during final tuneup to equalize performance of RX and TX [/LIST] The Varactor D11, a 1SV63 is about 22~26pF at 1 volt can be as low as 6pF when it tries to lock on 40 - this voltage pulls at the junction layer, making this gap smaller - lessening the capacitance - raising the resonate frequency combined with L15's inductive behavior. Going to channel 40 changes (lessens) D11's varactor capacitance Pushes up the resonate ring frequency Pin 9 sees from the output of TR11 TR12 just buffer amps the TR11 results and shoots it two ways, one to TP3 the other to IC2 - thru L16 [LIST] [*]- so L15 is your CRITICAL component. You have to get it ringing to even push a signal into TR12 and L16. [*]- so if you're not getting anything at TP3 - a new Crystal Filter is just going to sit there - just like it's predecessor [LIST] [*]- so don't throw too much into the radio for the parts you may need to fix it are more important right now to make it work. [/LIST] [/LIST] [/QUOTE]

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