[Denis G4DWC]

First off, thank you so much Terry for reproducing this fine circuit diagram for the FT290.

Now then, many years ago I had a problem with my FT290. As far as I recall, it was tuning the same parts of the band twice although the display indicated correctly. In other words, Tuning 144 to 145 was OK with the display indicating correctly but 145 to 146 on the display was still tuning 144 to 145. I located the problem to one of the two SIL Resistor Networks RB01 and RB02 to the right of Q01. At the time I purchased two of each from a dealer which fixed the problem. As those two Resistor networks don't have their values on the circuit and as I still have the spare ones in one of my component drawers I thought I would measure them which may help others in the future.

Both Networks have a white Dot which I will refer to as Pin 1 and which would normally be the common point of a commoned resistor pack. I measure the following on RB01:-

1-2 149.33k 1-3 248.85k 1-4 450.58k 1-5 49.68k
2-3 298.91k 2-4 501.11k 2-5 99.66k
3-4 600.62k 3-5 199.24k
4-5 400.91k

It looks like Pin 5 is probably supposed to be common which, after taking account of the tolerance would give :-

5-1 50k 5-2 100k 5-3 200k 5-4 400k

I measure the following on RB02

1-2 293.32k 1-3 343.53k 1-4 443.46k 1-5 645.70k 1-6 243.46k
2-3 149.90k 2-4 249.98k 2-5 451.84k 2-6 49.82k
3-4 300.09k 3-5 502.42k 3-6 100.07k
4-5 602.60k 4-6 200.09k
5-6 401.87k

RB01 is shown with a through connection but I don't think that's the case from measurements. I assume that only three of the resistors are used and that the through connection is only shown to save space on the diagram. I'm not keen to open my working unit to verify this.
Anyway there should be enough info above to check these networks.

Regards
Denis