[morzh]

Loctal contacts are way worse then old style....had similar problems with my portable Zenith 6G001. Deoxit did not help much. The contacts simply get loose and just a little dirt coupled with that is enough to deliver trouble.

I also notice something yesterday that could be a microphonic, but not sure - it only appeared on one song and was not there before that or after, this was while listening to the local station.
So I decided to withhold e judgement for a while.

As for teh micrphonic..

1. Is it my impression or 70 chassis is really flexible and is thinner sheet metal than in 90? When I pick it up, it clearly twists where the power transformer is under its weight; don't remember this in the 90 (or 20).

2. Could be a tube.
3. Have you replace the tuning cap's grommets?
4. Have you installed any caps (except the line filter) other than film or mica?
5. Is everything tightened well?