Author Topic: Marconi 2022A  (Read 1799 times)

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Offline david69

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Re: Marconi 2022A
« Reply #25 on: April 15, 2021, 06:03:54 pm »
Ahoj George,
I have replaced some actives and passives components, so it looks like better :)
One small bug is small self oscillation about 150MHz, but all range 10kHz to
1000MHz is clean and output voltage is adjustable in all range
The gener was really in bad condition, and still have unreadable display.
 

Offline david69

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Re: Marconi 2022A
« Reply #26 on: April 22, 2021, 03:06:54 pm »
Ahoj Georgu,
HF ALC amplitude modulation produce noise in range 150MHz, there is mixed signal 350kHz
which destroy output of AB1 board. Modulation is switched off.
 

Offline david69

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Re: Marconi 2022A
« Reply #27 on: April 23, 2021, 07:06:59 am »
Level Control C5 is oscilating, DAC with CA3046 not work properly
 

Offline david69

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Re: Marconi 2022A
« Reply #28 on: April 24, 2021, 10:33:28 am »
add resistor 22 Ohm to divider against self oscillation in band 125Mhz - 250Mhz
 

Offline david69

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Re: Marconi 2022A
« Reply #29 on: April 24, 2021, 04:43:47 pm »
CA3046 replaced by two BC546 tranzistors and add 15pF cap between outb and refb pins of DAC.
Gener is OK, no oscilation, correct voltage level in all band :)
 


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