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Hi Andrew. I noticed this too on an AM board I have here. I discovered it was done in the factory on later boards due to an earth problem causing hum if I remember right. Each section of the board

Hello, I had a look at the AM board and it seems to have been modified ... Is that from factory and what is this for? AM doesn't work that's why I pulled the board. 73

Thanks ! I just wanted to be sure that the replacement fan I intend to use will be oriented the right way. 73, Jacques, VE2JFE in Montreal

Hello, The fan draws air out. So in other words it blows to the rear. This way the heat from the valves gets extracted from the case.

Hi Roger Thank you. I have tried that with no success and no discernable change in the frequency either (swapped out D13 as well).???Whole thing is not making much sense to me at all! 73 Grant

Hi Grant, I would go back to the relay contacts again. Using a grounded probe jumper the C5 contact to ground. If that doesn't help ground the clarifier switch contact connected to D13. 73 Roger

Hello group (This also posted elsewhere) After almost a 12 month postponement with a number of other more straightforward projects suddenly taking up bench space I'm back onto this elusive problem

Ahh .. thank you ... I knew this project would be educational! I initially assumed the 'Marker' would be an RF signal but then looked at the circuit and started to scratch my head! 25KHz to 14.2MHz

Harmonics. The fundamental 25 kHz signal is typically a square wave that is rich in harmonics well up into the VHF region. That is also why the accuracy of the marker decreases as you go up in

Hello, I'm wondering how the Marker signal which seems to be a 25KHz NF signal actually leads to a signal 'received' on 14.2 MHz ...? Any input appreciated 73

Hi Don, I don't have a signal generator but a 4 channel digital scope. I could buy a cheap QRP PIXIE as signal source or? use the marker signal and feed it back into the RX socket. I've now

If you don't have a generator, a piece of insulated wire hooked to your antenna and with the rig tuned to. 074, the FT 8 spot should be a usable reference for an injection probe. Don ve3ids wrote:

Do you have a signal generator? If you do, inject a signal at the point where you have both the Red and Green Arrows marked and see if that is normal sensitivity. If it is, work back to the antenna

Reporting back .. Removed both covers and traced the RX signal line via the ATT switch to Trimmer Board A. I measured continuity between *'RX Antenna In' -> Switch -> choke* and it was fine. The

Well, when you open it and look for yourself, the display unit is kind of in the way so for me it was A LOT easier to remove both the display unit and the four screws holding the VFO, then slide the

As per subject line ... Thank you

Yes, I was thinking about exactly this. I'll have to wait for the Contact Cleaner to arrive, once it's here I'll open the radio and will inspect the switch.

Before going too far, try jumpering the attenuator switch. That should localise the problem. George, G8AOJ -- George Smith - RSGB, D

One thing you could try is to gently work the ATT switch back and forth like 50 times. That often works for a little time. Sent from Gmail Mobile Chuck Chandler chandlerusm@...

The signal from the antenna connector followed the Red marks through the att switch and to the front end of the receiver. The marker is the Green mark which is injected after the att switch. With the