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Hello Everyone,
Is there a switching relay that clicks over to turn on the receiver right after you press the power button?
If so, is that relay serviceable?
Tonight when I switched on the radio, the receiver did not come on. The ALC meter was at the half way point. All controls and buttons frequency display are fine. I powered it down, then tried power cycling it on and off several times. No change.
I came back later and tried again and it powered right up and the receiver turned on.?

罢丑补苍办蝉….

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Hi Leo,

There are a couple of RX/TX relays in the FT-980. The most obvious one is the head which switches the path between the PA and the receiver. Three is another (multi-pole relay) on the REG board that switches a bunch of circuits. However, all these relays "default" to the RX position which would not match your symptoms (especially if the receiver was working when you switched it off).

I have found two potential things that DO cause this ... although the list is longer:
1. Intermittent connections, especially connector solder joints on the PCBs. A simple intermittent "RX G" or "RX 13.5V" line to one of any of the AF, RF or other boards would cause this. I had an intermittent connection on the BFO mixer xformer myself. These old single-sided PCBs are known for this type of thing.
2. BFO oscillator (or other independent oscillator) not starting up properly. This can happen due to parts going out of spec, flux contamination, etc. I had to replace a trimmer cap on an oscillator once to get the oscillator to start working again. You can sometimes debug these by switching the mode, and checking to see if you can receive in FM, but maybe not in SSB/CW (or some other combination). Then check the signal path charts in the technical manual.

If it happens again, I recommend first trying all different bands/modes/etc and see if it works in some but not others. Then, rotate the rig (yeah, I know it is heavy), and see if it is intermittent to mechanical displacement/vibration.

Just my thoughts,

Mat, N8TW



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-Mat Breton, N8TW

Thanks for your detailed reply.?

I did also noticed that while this is happening, switching the mode switch, all modes are shown selected on the display except FM. When the receiver is restored, FM is shown on the display and all works fine.
I stand corrected, the meter that sits half scale while this is happening is the meter on the left not the ALC.?

Ahhhh ... very good: the left meter position "might" be a critical clue.

Two questions:

1. The left meter is the "multi-meter". What position is the multi-meter mode knob (to the right of the two meters) in? It will be on of "VCC", "IC", "COMP", "PO", or "SWR".
2. When the receiver is working, I am assuming that the multi-meter is no longer "mid-point", correct?

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-Mat Breton, N8TW

Hi Mat,
Here is a quick video clip of the actual issue.?

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I did notice that while making this video clip, the receiver seems to switch on when the mode switch is in the FM mode even though FM doesn’t appear while in this state.?

First off, congrats on having TWO FT-980's!

Wow: I watched this video twice. I haven't seen this one before.? I'm going to have to mull this on over.

First off, I'm not sure why the FM VFD segment doesn't come on when the switch is in FM. Then we have the whole boots up OK in FM, but not in other modes. And if you switch to any other mode from FM it switches. Very likely all related ... but it isn't triggering anything yet. I'm going to have to look at the signal paths to see if I can see something. I wonder if we lost a uC I/O multiplexer or something ... they have been known to die.

Q: Can you check to see if it is actually transmitting (is it in transmit mode), either by checking the TX-GND pin on ACC2, or check the actual power output when using? a mic or something?




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-Mat Breton, N8TW