Lincoln gone nuts

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NightProwler
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Lincoln gone nuts

Post by NightProwler »

Hey all, So my MK1 Lincoln has gone loopy. It was working fine until one day I noticed the band seemed quieter than normal so I checked the Lincoln out and found it's now TX and RX'ing about 1MHZ out. If it's showing 27.555 it's actually on 28.7something. Any ideas?

Cheers all...Rich
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13EL121
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Re: Lincoln gone nuts

Post by 13EL121 »

I would start with checking the PLL board, all frequencies and voltages to measure can be found in the service manual. Maybe there is a fault in the PLL area. Depending on production year, the electrolytic caps start to leak or dry out after all the years.
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Otter
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Re: Lincoln gone nuts

Post by Otter »

Does the TX / Rx frequency change as you adjust the displayed frequency? If so, is the offset always the same? (Try 26.25, 26.75, 27.25, 27.75, 28.25, 28.75, 29.25, 29.6 MHz).
What is the part number on the CPU?
If the radio transmits, the low frequency PLL should be locked. I would guess that either the high frequency loop isn't working properly, the PLL0305A chip is broken, a reference frequency is broken or the CPU has gone faulty.
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NightProwler
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Re: Lincoln gone nuts

Post by NightProwler »

Cheers guys. I'm in work at the moment but when I have time I will look at what PLL is in it. I have a box of scrap Lincoln parts here so I could swap the PLL over. I'm in no rush as I have a another I use. Cheers...Rich
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