The Defpom Forum, for RadioMods, S&M Software and Music by The Defpom

And another strange thing, but that might just be how it's supposed to be, but the squelsh seems a bit odd aswell. There is just a tiny opening where it lets noise through. When it fully open (counter clock wise position) it closes as if i move it way up clock wise. But when i move it clock wise it ...

new info I've messured Q8 again. Fun part as i see Q8 as a transistor for amplification, correct me if im wrong. But when i messure Q8 with the rf control knob turned fully counter clok wise it gives me higher voltage as if i messure it with rf knob fully clock wise. Will that say that the amplifica...

Hi Scott I've lifted (removed) resistor R27 (R37) the one near Q8. I seems to have to do with the rf control button on the front as this stops working which also fits with the agc. The result was : No change when using the rf control knob on the front of the radio. The radio became even more deaf. C...

Thanks Scott

Will look for that tomorrow after work
I noticed that fault on the layout too, and it pussled me a bit. I've done some tracing on the pcb aswell and think that it might be a smaller project now finding that resistor.

But I'll let you know when it's done.

D3 and D4 seems to hold.

There are through the right way and blocked the other way. Both soldered loose and tilted from solderjoint so that i only messured the diode.


Still trying to locate R37 on the pcb though, thats a little nasty resistor that keeps hiding from me

Hi Defpom Yes after looking at the diagram i had an idea that it might not be R57 as it goes to ground ;) Will lift R37 tomorrow and see what happens. I do hope that it'll do something. The D3 and D4 I have found on the schematic as well, I just have to find them on the pcb tomorrow and have to find...

Thanks for the replies KC7NOA and Defpom. I'll try to bypass the lowpass filter. I've uploaded a schematic diagram that I hope is better than the one you got Defpom. RF control button on the front does change the sensitivity at the signal. From absolutely nothing at ccw to just barely audioble at fu...

Today I've been doing the following.

Changed C486 and C487 both 330uF 10V to 330uF 35V.

A bit overkill at the voltage ratings but that's what my parts pusher had.

Changes : None.

Mesured voltage at some of the transistors on the upperside of the pcb. Used chassis as minus/ground. All mesurements are done with squelsh open. Q8 - 2SC1674 - Base = 3,3V - Collector = 6,3V - Emitter = 4,7V Q213 - 2SC1675 - Base = 0V - Collector = 7,2V - Emitter = 4,0V Q412 - 2SA950 - Base = 7,8V ...

Radio Make and Model: President George PCB Number: PB-334AA PLL Number: Test gear available: Signal Generator, Analouge Voltmeter, Digital Voltmeter, Frequency counter, Osciloscope, access to test station with Sinad meter. Symptoms: Radio is deaf, can just hear audio from signal generator way down i...