# Sequential Six-Trak - Need the spec on a fried diode **URL:** \ **Category:** Synth Repair\ **Tags:** no-power, sequential, six-trak\ **Created:** [October 10, 2025, 6:17pm UTC](https://forums.syntaur.com/t/sequential-six-trak-need-the-spec-on-a-fried-diode/9180 "2025-10-10T18:17:00Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![Dr.Theopolis](https://forums.syntaur.com/letter_avatar_proxy/v4/letter/d/7993a0/32.png) [@Dr.Theopolis](https://forums.syntaur.com/u/Dr.Theopolis)\ **Post date:** [October 10, 2025, 6:17pm UTC](https://forums.syntaur.com/t/sequential-six-trak-need-the-spec-on-a-fried-diode/9180/1 "2025-10-10T18:17:00Z")
[Sequential Circuits] [Six-Trak] – [Fried diode] I was wondering if someone might know the replacement spec for a fried diode in my Six-Trak. It is one of 4 (all the same), probably part of a rectifier series near the battery. There are no markings on these other than “4•B”, black casing with a blue cathode band though I’ve seen other Six-Trak photos showing them in a more common silver band as well (mine may be an early model). This was due to a failed voltage regulator which I have since replaced. Thanks for any thoughts or recommendations! ![Six-Trak_Fried_Diode](https://forums.syntaur.com/uploads/default/original/2X/5/579e7a2061b6cde0c8e6f2ff649e4361e780e77b.jpeg) ---
**Author:** ![sargfowler](https://forums.syntaur.com/user_avatar/forums.syntaur.com/sargfowler/32/2120_2.png) [@sargfowler](https://forums.syntaur.com/u/sargfowler)\ **Post date:** [October 11, 2025, 7:39am UTC](https://forums.syntaur.com/t/sequential-six-trak-need-the-spec-on-a-fried-diode/9180/2 "2025-10-11T07:39:25Z")
They look like general bridge rectifier diodes. They’re in the power supply section right? Is the power coming in AC? Might be worth removing them all and replacing with a 100V 5A, Schottky Diode ---
**Author:** ![Dr.Theopolis](https://forums.syntaur.com/letter_avatar_proxy/v4/letter/d/7993a0/32.png) [@Dr.Theopolis](https://forums.syntaur.com/u/Dr.Theopolis)\ **Post date:** [October 11, 2025, 10:52pm UTC](https://forums.syntaur.com/t/sequential-six-trak-need-the-spec-on-a-fried-diode/9180/3 "2025-10-11T22:52:07Z")
Yes that’s right. I have some spare 1N4002’s which look to be used in the schematic at multiple places that may work as well (they’re rated 100V @ 1A ). I agree though, unless I had the exact replacement that all 4 should be replaced with same types just to be consistent. ---
**Author:** ![sargfowler](https://forums.syntaur.com/user_avatar/forums.syntaur.com/sargfowler/32/2120_2.png) [@sargfowler](https://forums.syntaur.com/u/sargfowler)\ **Post date:** [October 13, 2025, 7:15am UTC](https://forums.syntaur.com/t/sequential-six-trak-need-the-spec-on-a-fried-diode/9180/4 "2025-10-13T07:15:36Z")
Just check there are no shorts after that blown diode. There might have been a reason it failed ---
**Author:** ![Dr.Theopolis](https://forums.syntaur.com/letter_avatar_proxy/v4/letter/d/7993a0/32.png) [@Dr.Theopolis](https://forums.syntaur.com/u/Dr.Theopolis)\ **Post date:** [October 16, 2025, 3:33am UTC](https://forums.syntaur.com/t/sequential-six-trak-need-the-spec-on-a-fried-diode/9180/5 "2025-10-16T03:33:14Z")
After replacing the bad LM337T and all 4 rectifier diodes with the 1N4002’s, I can report that everything seems to be working correctly once again. I didn’t find any other component issues or shorts anywhere else. I’ll probably go ahead and re-cap everything while I’m at it just to future proof it. Very odd indeed, but it appears to be fine after leaving it on for a couple of hours and testing all functions. Thanks for everyone’s feedback on this.