Trouble with Alignment and Test, Part II

[mikekopacki]

I ran into a little snag here and if anyone could help, I'd appreciate it.

I have ser# 4619, just started the Alignment and Test, Part II.  I

In the VCO Alignment steps, I obtained the following results (Table 6-1. VCO Voltage Readings):

Band    Low Freq.    Voltage    High Freq.    Voltage
80m      3500              2.0            4000          6.0
40m      7000                .03          7300            .03
30m    10000                .03         10150            .03
20m    14000              2.3           15000          3.89
17m    18000              2.99         18200          3.18
15m    21000                .03         21450            .03
12m    24800              3.84         25000          4.21
10m    28000              3.16         28800          3.97

As you can see, the readings for 40m, 30m and 15m were not within range (1.5v - 7.5v).  I checked all components (L30, D21-D26, and C71-C74 and the correct values were installed).  T5 has the correct number of turns.  I tried adjusting L30, per the instructions to move all the readings upwards, but adjusting L30 had no effect on the voltage reading for the affected bands.

Just to repeat that, I adjusted L30 while watching the voltage readings, and it did not change the readings on the 3 affected bands.  It did change the readings on all the other bands.      

If anyone can help, many thanks!

Mike, NJ2OM
               
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[Don Wilhelm-3]

Mike,

Try this - first go the 4000 kHz and adjust L30 until the voltage raises to
somewhere between 7 and 7.4 volts.  Then see what the voltage is when tuned
to 7000 kHz - expect something around 2 volts.

If your voltage at 7MHz is still 0.03 volts - you have a problem.  Look at
the schematic for the RF board (Appendix B) sheet 1 of 4, and identify all
the components associated with the VFO Range Selection area (top of the page
center below  the PLL Synthesizer).

Check all those components for proper values place into the correct holes,
and proper soldering - including the relay terminals (those are easy to miss
if not soldered).  Check for excess solder or an unclipped lead that might
cause a short only when one of the relays is in the set position.

You are getting a proper range of variation when tuning from one end of the
band to another, so the basic PLL/VCO is working, your problem is limited to
having the frequency correct, and that is associated with relays K13, K14
and K15 plus the capacitors that are connected to these relay points.

73,
Don W3FPR


----- Original Message -----

I ran into a little snag here and if anyone could help, I'd appreciate it.

I have ser# 4619, just started the Alignment and Test, Part II.  I

In the VCO Alignment steps, I obtained the following results (Table 6-1. VCO
Voltage Readings):

Band    Low Freq.    Voltage    High Freq.    Voltage
80m      3500              2.0            4000          6.0
40m      7000                .03          7300            .03
30m    10000                .03         10150            .03
20m    14000              2.3           15000          3.89
17m    18000              2.99         18200          3.18
15m    21000                .03         21450            .03
12m    24800              3.84         25000          4.21
10m    28000              3.16         28800          3.97

As you can see, the readings for 40m, 30m and 15m were not within range
(1.5v - 7.5v).  I checked all components (L30, D21-D26, and C71-C74 and the
correct values were installed).  T5 has the correct number of turns.  I
tried adjusting L30, per the instructions to move all the readings upwards,
but adjusting L30 had no effect on the voltage reading for the affected
bands.

Just to repeat that, I adjusted L30 while watching the voltage readings, and
it did not change the readings on the 3 affected bands.  It did change the
readings on all the other bands.



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