Traffic receiver

LA1DEA wrote:Trying to upload the full documentation of the receiver, but ther is a problem.
The forum dont accept PDF upload????
73 LA1DEA

I am not 100% sure, but I think it does not. You may send the PDF to Harry, the owner of this forum, via e-mail and he can make it accessible on HHH pages.

73 Ivan OK1SIP

Trying to upload the full documentation of the receiver, but ther is a problem.
The forum dont accept PDF upload????
73 LA1DEA

There is another strange resistor network there. It is hard to figure out how it works, moreover without part values. What is the SPDT switch next to the double diode for? Anyway, LF modulation and AVC voltage are taken from that tube.

VBR fron Ivan

I guess there must be an issue regarding the double diode 7A6.
I think that the "first" catodes shoud bee grounded???
73 LA1DEA

Thanks Ivan
73 LA1DEA

Hi,
such a great mistake like drawing several excessive resistors seems improbable. In any case, the S-meter is not crucial for the function of the RX. If you are going to repair/restore one, hold on the real circuitry instead of the schematic. If you want to make a free copy of the receiver, omit the S-meter or connect it as you consider the best.

VBR from Ivan

Thanks for respons
I dont think there should be an connection at pkt.1 because I cant see why the AVC signal has anything to do with the high voltage supply to the anode of 7A7.
I think that the AVC signal should go directly the the S-meter
73 LA1DEA

No, I am not sure. But R6 and P1 may be in parralel. I guess P1 is used during RX calibration only.

It looks like this schematic uses symbols of cross = connection, a small semicircle = no connection. Some other schematics use cross = no connection, cross with round dott = connection. It is rather confusing.

VBR from Ivan

Tanks for respons. Very good answare.
But are you shure about pkt 1? If there are a connection then R6 and P1 are in parallell?
73 LA1DEA

Hi,
it is quite a puzzle   IMHO all three points shall be connected, but there is a mistake at the area of the intput.

R5, R6, R11 and P1 form a kind of bridge. The connection from R5/R6 shall lead to the point R3/C8 and not to the ground. This way the meter can show the AVC voltage in fact. The "J" is an external ground connection of the chassis, not connected with R5/R6/P1.

Point 2 is surely connected, it is the ground connection of the filtration capacitors and the BFO. I wonder why the center of the secondary of the power transformer is connected to the ground in another point than the filter...

Point 3 seems to be connected as well - it sets the AVC voltage to 0V when the BFO is in use (CW/SSB).

VBR from Ivan OK1SIP

Hi
I have a question regarding enclosen picture.
Is the a connetion on 1, 2 and 3?
If there are there connection on 1, then high voltage is shortcutted to ground. 
If no connetcion then R6 and R11 are in parallell to ground.
I guess the are drawing fault in area around S-meter-
Hope anyone can help me?

73 LA1DEA