SDA

Studer A800 Resurrection…

Author: matthew; Published: Dec 27, 2008; Category: New Studio; Tags: ; No Comments

Way back in ought-six, Steve, the owner of Echo Mountain, acquired three Studer A800 machines in dubious condition. One was rebuilt and has been in use as Echo’s 2″ 8/16/24 track for the last two years. The remaining two have languished in the amp room as parts machines, keeping the primary 24-track working more or less flawlessly. They came in on a truck from NYC and all had been mostly stripped of tantalum/poly caps due to someone deciding that capacitor technology was old and bad and would catch fire. While it’s true that tantalum caps love to fail short I think the solution applied of replacing them all with electrolytics was ill-chosen as a long-term remedy, but great for job security for whoever gets to re-cap the machine every five or ten years. It’s true, we decided to stick with electrolytics as the more durable technologies are crazy expensive. So, I give you the re-cap team:

This project took place during two four-day sessions over the last two months and was overseen by Greg McNeer and myself. Prior to working on the tape machine itself I robbed the power supplies from both for rebuilding. Each A800 has five separate power supplies in a sweet daisy chain. The audio supplies have a fancy interlock while the transport/logic/etc. supplies are more straightforward.

Problem – Like most 80′s technology the wires carrying power and the .1″ molex used to connect it aren’t really rated for the current demanded (and heat created) by the machine, so the wires are brittle and corroded and the connectors are stiff and burnt.

Solution – Replacing worn-out wire and parts. I selected some 16 ga. wire with a higher-temp insulator than the original and kept wire colors the same so the excellent manual could still correspond to the real circuit. I didn’t have a better connector option that I could stuff in the holes available so i stuck with sweet sweet molex.

Problem – The middle audio supply negative rail is getting pulled down.

Solution – An electrolytic in the back plane of the middle card cage has failed short. With it replaced all power supplies are operating to spec.

The heads have been sent for re-lapping and capstan and tach rollers sent for sandblasting. The tape path is square according to the alignment blocks.