Comments for page: Eico Cortina 3070

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Posted by Steve L. March 28, 2022 - 03:21 pm
Hi Walt, Yes, replacing the C103 caps is well worth doing. Hi-K ceramics are only good for applications in which distortion and accuracy don't matter at all, like power supply bypassing. Their capacitance can change markedly with time and voltage. Eico really shouldn't have used them in this application.

Posted by Walt N March 28, 2022 - 02:48 pm
OK. BTW, I did not replace the C103 caps that you said should probably be replaced. Do you think that is worth doing?

Posted by Steve L. March 28, 2022 - 02:24 pm
Hi Walt, Yes, I think those Q102 collector voltages will be okay. By the way, I notice that the schematic shows 9.4V at that point, so that's a bit closer to what you are reading.

Posted by Walt N March 28, 2022 - 02:12 pm
I ran the "no load" voltage checks as per the Cortina manual on the phono preamp. All of the transistors read high, but within tolerance (15%) EXCEPT for the Q102 Collector. That one is supposed to be 10.4V. I got 7.1 (DMM) and 7.6(VTVM) on the bottom one and 6.6(DMM) and 7.0(VTVM) on the top. This is about 30% off. I'm not sure whether to suspect the transistor or some other component, or is this OK?

Posted by Steve L. March 25, 2022 - 03:20 pm
Hi Walt, I would call the 2N5089 an upgrade. In the Cortina, it should not increase the output.

Posted by Walt N March 25, 2022 - 03:11 pm
Is the 2N5089 a more or less exact replacement, or is there a chance that using it would increase the output?

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