Current project is a MX110Z, and two IF transformers are definitely suffering silver mica disease. Has anyone compiled a list of IF transformers and their capacitor values? It would be nice to have the caps on hand and do the repair all at once, and not have to wait for parts to arrive after deducing the capacitor values. Most, if not all, of Mac's IF transformers in the tube era were made in New Jersey by the Automatic Manufacturing Division of General Instrument Corp., so there it is probably there is enough consistency to chart them (i.e. I assume all cans stamped with the same numbers will have identical inductors and capacitors). If there is no list, perhaps we should set up a system to create one. (I also have an MR65B, MR71 and Mac 1500, so I've seen a lot of these transformers. Maybe too many.)
IF Tranformer Cap Values
- Thread starter Thoan
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clinic-audio
all on YAMAHA untill 1990
Hello
Yes, this desease is a problem
This is the only presious information which is not on schematics
Yes, this desease is a problem
This is the only presious information which is not on schematics
When I run into silver mica disease in an IF transformer, I break the entire mica wafer out of the transformer, then I reinstall the transformer in the unit. I then temporarily install a pair of rather large wide range variable capacitors (large ceramic base trimmer capacitors) I have made up for testing (with long stiff leads), under the chassis, connected in parallel with the primary and secondary legs of the transformer (where the mica capacitors inside the transformer effectively were in the circuit). I operate the unit, and adjust the two capacitors for best resonance of both windings, then remove the capacitors and measure the capacitance. I then install the closest value of NPO ceramic disk capacitor in on the transformer legs (under the chassis), and touch up the alignment with the slugs.
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