Aggravated SONY TA-F444ESII ATTENUATOR/Volume control

[Davejames73]

Thanks Goldie99, I will be replacing the resistors once they get here. The only fusible resistors in spec were the 10ohm all others were way out. I'll report back once I have them installed. Thanks

 

[TD1]

Recently picked up a TA-F444ES II said to be in good working condition and stored for about 20 years. Prior to connecting it to anything I measured the bias and DC offset (both in spec), then probed each fusible resistor. Most were close to spec, some were at or above the 5% tolerance limit, and a few were way out:

• R512 - 91 ohms spec, 127 ohms measured
• R562 - 91 spec, 128 measured
• R516 - 180 spec, 197 measured
• The 10 ohm resistors were all in the 10.5 - 11.0 range.

R512 and R562 are part of the Class A section, whereas R516 is part of the temperature compensation, according to the schematic. I'll probably change these out, at least, then think about replacing the eight 10-ohm nominal resistors.

Tim