# Tc1-1-13ma+

**URL:** <https://discourse.myriadrf.org/t/tc1-1-13ma/13333>\
**Category:** LimeSDR\
**Created:** [17 September 2026 10:27 UTC](https://discourse.myriadrf.org/t/tc1-1-13ma/13333 "2026-09-17T10:27:33Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![WA4SIX](https://avatars.discourse-cdn.com/v4/letter/w/94ad74/32.png) [@WA4SIX](https://discourse.myriadrf.org/u/WA4SIX)\
**Post date:** [17 September 2026 10:27 UTC](https://discourse.myriadrf.org/t/tc1-1-13ma/13333/1 "2026-09-17T10:27:33Z")

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I am trying to identify an issue with my Limesdr-usb. When looking at the V1.4 schematic, the TC1-1-13MA+ shows as a center tapped primary. The datasheet shows there is no center tap. Should I just use the TC1-1-13MA+, or was it changed in the production run? Take TX1\_1 for example. It clearly shows a center tapped primary. Trying to diagnose low power out & cannot make correct measurements.

Thank you,

Ed

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**Author:** ![andrewback](https://avatars.discourse-cdn.com/v4/letter/a/22d042/32.png) [@andrewback](https://discourse.myriadrf.org/u/andrewback)\
**Post date:** [24 September 2026 08:26 UTC](https://discourse.myriadrf.org/t/tc1-1-13ma/13333/2 "2026-09-24T08:26:18Z")

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Tagging @Zack

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**Author:** ![Zack](https://yyz2.discourse-cdn.com/flex034/user_avatar/discourse.myriadrf.org/zack/32/89_2.png) [@Zack](https://discourse.myriadrf.org/u/Zack)\
**Post date:** [24 September 2026 11:44 UTC](https://discourse.myriadrf.org/t/tc1-1-13ma/13333/3 "2026-09-24T11:44:41Z")

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The symbol for TC1-1-13MA+ has been initially reused from another Mini-Circuits part which has the same physical pin count. For TC1-1-13MA+ pin 2 is unconnected to the coil and is just grounded to avoid floating. And yes, TC1-1-13MA+ doesn’t have a center tap, so, basically, pin 2 is just grounded.