| Posted by
Walt N. |
November 22, 2021 - 01:54 pm | |
| It appears I have it correct, just wanted to make sure. Thanks for the comments. Getting close to done on the re-cap. Try it soon. |
| Posted by
Steve L. |
November 21, 2021 - 03:00 pm | |
| Hi Walt, Yes, the C and B pins on the 2N5089 are swapped relative to those of the 2N3391A. The E pin remains in the same place, relative to the package shape. I take it you would like to have a way to verify the Q201 connections. Near the top of the second page of this article is a picture of the 2N5089 with the pins labeled. I believe Eico has labeled the pins on the silkscreen, so you can match them up. As a further check, the C pin goes to R202, which should be a nearby 4.7K resistor, so you will be able to measure continuity. Let me know if you need further assistance on that. |
| Posted by
Walt N. |
November 21, 2021 - 12:13 pm | |
Replacing Q201.
The 2N5089 has a different lead configuration than the original EICO transistor. I want to make sure that I'm not screwing up before I apply power as I have replaced the original because I remember the noise from "back in the day" when I had one of these. |
| Posted by
Steve L. |
November 12, 2021 - 02:01 pm | |
Hi Walt, Yes indeed, all Reader Comment sections on Tronola.com are active. We are notified whenever there is a post and endeavor to answer asap. By the way, your browser page may need to be refreshed to see a new posting.
And yes, you should replace C5 and C6 even without the transistor replacements. The issues they fix are independent of the transistor changes. To measure Iq, put the DMM probes across R12 (or R14) for the left channel and R11 (or R13) for the right channel. Since those resistors are 1.0 ohm, the current in amperes will be read directly in volts. For example, if the DMM reads 0.033V, that indicates 0.033A = 33mA. Cheers |
| Posted by
Walt N. |
November 12, 2021 - 01:34 pm | |
I hope this may still work. I'm no more than a hobbyist. I am about to order new electrolytics for my recently acquired 3070.
1. Should I order 4700uF caps for C6 even if I don't replace the transistors? Will it hurt?
2. Assuming I do replace them, I have no idea how to calculate or measure Iq once the pots and resistors are installed. Can anyone help me here? I DO have a good meter and a scope. |
| Posted by
Steve L. |
October 02, 2021 - 04:41 pm | |
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