Romanian-labelled schematic of a preamplifier with tone corrector, meaning a bass and treble tone control section, provided as a 330 KB PDF. No manufacturer or model is given in the name, so it is best treated as a generic DIY circuit. The diagram is handy for following signal flow through the gain and equalisation stages, identifying potentiometer wiring and checking capacitor values that shape the frequency response. Open it in a standard PDF viewer and verify supply voltage requirements before building or repairing.
The button opens the matching file on RM Schematics, or a source page if it is not catalogued there yet. The original attachment is from @pdf_servicemanual. Enginerys does not host this file.
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The standard format for schematics, block diagrams, power-sequence charts and service manuals.