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585pll [2007/09/04 12:37]
n5na
585pll [2015/02/09 10:37] (current)
n1eu
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 Pressing on the board or flexing it can sometimes cause the problem. Other symptoms are distorted received SSB signals or warbly CW tones. Pressing on the board or flexing it can sometimes cause the problem. Other symptoms are distorted received SSB signals or warbly CW tones.
  
-Also check the VCO for each band. There is a test point at the junction of Q1-C and Q3-C. The test point voltage will range from about 2.8 V to 7.6 V DC fron the low to the high end of the VCO range. You can tweak the slugs in the VCO cans to alighn ​them. Count the VCO shield cans from left to right when loooking at the board with the rigs front panel facing you. The VCO ranges are a follows:+Also check the VCO for each band. There is a test point at the junction of Q1-C and Q3-C. The test point voltage will range from about 2.8 V to 7.6 V DC from the low to the high end of the VCO range. You can tweak the slugs in the VCO cans to align them. Count the VCO shield cans from left to right when loooking at the board with the rigs front panel facing you. The VCO ranges are a follows:
  
   - 22-30 MHz   - 22-30 MHz
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 VCo's are selected by voltages on connector 90 (left to right 1,2,3,4). Each connector pin will go to 0 V when that VCO is selected. The pins corresponding to the unselected VCO will remain at 5 V. VCo's are selected by voltages on connector 90 (left to right 1,2,3,4). Each connector pin will go to 0 V when that VCO is selected. The pins corresponding to the unselected VCO will remain at 5 V.
  
-In some cases you may need to resolder the connections on the minor loop board. This is tedious, because the shield on the bottom of the board has to be unsoldered and removed to get at the connections. If you do this, save yourself a repeat ​ operation by esoldering ​the entire board.+In some cases you may need to resolder the connections on the minor loop board. This is tedious, because the shield on the bottom of the board has to be unsoldered and removed to get at the connections. If you do this, save yourself a repeat ​ operation by resoldering ​the entire board.
  
-I found that some of the little transformers,​ the ones with the ferite ​cores an colored wire wound through them, were microphonic when I poked at them. The cure was to flow some clear nail polish into them. Q-dope or epoxy should also work well, provided it can flow into the holes in the core. Some of the aluminum electrolytic capacitors were also microphonic. I replaced them with tantalum types.+I found that some of the little transformers,​ the ones with the ferrite ​cores and colored wire wound through them, were microphonic when I poked at them. The cure was to flow some clear nail polish into them. Q-dope or epoxy should also work well, provided it can flow into the holes in the core. Some of the aluminum electrolytic capacitors were also microphonic. I replaced them with tantalum types.
  
 Lastly, and maybe you should try this first, some Paragons had a tiny trim pot on U3 on the major loop board. THis pot is sensitive and a small rotation will cause the PLL to go in and out of lock. Adjust the pot for a voltage of 3.2 V at the wiper, or set it to the middle of its lock range. The second thing to try is VCO alignment, but don't be surprised if you have to resolder all of the connections on the board anyway. Lastly, and maybe you should try this first, some Paragons had a tiny trim pot on U3 on the major loop board. THis pot is sensitive and a small rotation will cause the PLL to go in and out of lock. Adjust the pot for a voltage of 3.2 V at the wiper, or set it to the middle of its lock range. The second thing to try is VCO alignment, but don't be surprised if you have to resolder all of the connections on the board anyway.

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