[R-390] Filters

[quartz55]

Hi.  New to this group.

I have 2 R-390As.  Filters in one module seem fine, but the gain drifts, I'm working on that.  Other module has bad 2(weak) and 4(dead) but the 8 and 16 seem good, but different gain through them.

Was wondering if anyone has come up with a good cheap way to replace the filters?  Could it be possible to make an op-amp variable bandwidth 455 filter to replace the mechanical ones?  Don't know the voltages involved in the filters, but maybe too much for op-amp filters?

Is there any way to search the archives?

N3DT