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The 2022 has stored values for gain adjustment at various frequencies so can be tweaked a bit if stage gains have changed.
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I don't have a Mi2022 here and I've never been inside one but I don't think it has stored values for gain adjustment. Or maybe I've missed this feature somewhere in the schematic/manual?
However, like many sig gens I think it can allow user adjustment of the ALC (detector) target voltage according to frequency and store this info in memory as calibration data but none of this should need touching if the OM345s are swapped because they have nothing to do with the ALC detector accuracy. However, in theory at least, several replacement MMICs 'can' cause the sig gen ALC to go open loop if there is too much or too little system gain for the ALC system to cope with at some part of its operating ranges for frequency and amplitude.
That's why I think each person would have to 'prove' a complete suite of alternative MMICs from the OP by looking at the ALC margins across all the generator's ALC range across all frequencies.
This requires a lot of tests internally and some degree of understanding of how the ALC operates on each range. If I was doing this I'd automate the tests via a PC and GPIB (with a GPIB controlled DVM reading each ALC voltage) to prove the ALC margins were OK across all frequencies and RF levels in the ALC range. Otherwise it would take ages to do it all manually.
I know I'm being a bit of a neghead on this thread but this is a decent bit of test gear. Having looked at a typical OM345 module that has failed I think the easiest and cheapest (and best) way to repair the generator is to simply repair the OM345 and refit it. This way there would be far less risk of falling outside the ALC window somewhere in the generator's ranges and also the spurious performance would be similar to original
