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PCB Wizard PLLFM-1

Posted: Wed Aug 26, 2020 10:15 am
by Genie FM
Tried out one of these boards purchased in 2016 from the above seller on e-Bay .I connected up to 15v power supply, swr/power meter and dummy load. When powered up I noticed that it took ages to lock onto selected frequency and that all that time the full output power was available. Do modifications exist to add out of lock power down to this board and increase the lock-up speed? It seems to be based on a TSA5511 and PIC16F628A with a 2N3866A output transistor. Ta Mike

Re: PCB Wizard PLLFM-1

Posted: Wed Aug 26, 2020 10:24 am
by radium98
and ....?
any picture of what you speak off .with blind thing can not answer .

Re: PCB Wizard PLLFM-1

Posted: Wed Aug 26, 2020 2:12 pm
by teckniqs
I think the LED is just lazy and takes a while to come on, but if you get a frequency counter you will see it should be LOCKED tight on to the frequency after only about a second or two being powered.

Re: PCB Wizard PLLFM-1

Posted: Wed Sep 16, 2020 8:46 am
by Genie FM
Attached is a piccy of the PCB Wizard PLLFM-1. The LCD pins can be connected to a 1602A display to show frequency . But the board is very slow to lock (around 20-30 seconds) and there is apparently no OUT-OF-LOCK-POWER-DOWN. The Toko "Canned Coil" ihas no core (as supplied) The PA Transistor is a 2N3866A and the PLL Chip is a TSA5511. The core on the red coil is adjusted for maximum output with minimum harmonics and the nominal supply voltage is 15 volts dc.

Re: PCB Wizard PLLFM-1

Posted: Wed Sep 16, 2020 10:03 pm
by rigmo

Re: PCB Wizard PLLFM-1

Posted: Sat Sep 19, 2020 1:12 am
by Albert H
Genie FM wrote:
Wed Sep 16, 2020 8:46 am
Attached is a piccy of the PCB Wizard PLLFM-1. The LCD pins can be connected to a 1602A display to show frequency . But the board is very slow to lock (around 20-30 seconds) and there is apparently no OUT-OF-LOCK-POWER-DOWN. The Toko "Canned Coil" ihas no core (as supplied) The PA Transistor is a 2N3866A and the PLL Chip is a TSA5511. The core on the red coil is adjusted for maximum output with minimum harmonics and the nominal supply voltage is 15 volts dc.
It's a cut-down version of the BW exciter, missing OLPD because the lock output from the 5511 needs a little bit of additional cleaning up before it can be used. It has a simpler PLL than the BW job - Roger used a 145170 PLL IC (which has a better "locked" output) and used a dual-speed loop filter so that it would get to frequency quickly and lock, the when locked would slow down the loop filter (by switching the time constants using a 4066 CMOS switch) so that the modulation frequency response was good down to 20 Hz or so.

This cheapened and simplified version might work, but has to take a long time to lock if you want any bass through it, won't reliably indicate lock and won't turn off the output when it's not locked. You also won't get a Watt out of it - the 3866 needs more than 15V for that kind of power (unless you over drive it making lots of harmonic crap). Cheap 'n' nasty.