Studer A810 Issues After Battery Replacement

Is one of the settings for mute or to turn the level all the way down?

Of course, something else could have broken coincidentally, I hate that...

Check for the correct setting for DIP switches JS0-JS19, JS1-JS8 on peripheral control, and those on line amps.

yjwu

You didn't say if the audio was working correctly BEFORE replacing the battery. Same with the main audio output. If there were no problems prior to replacing the battery then I'd look for some cabling/connections that could have come undone during your repair. If it wasn't working beforehand, then I'd suggest checking the +/-15volts that go to each audio card. Got two 812's a few months back and had various bad/leaky capacitors which affected various operating modes. Per Ki Chioi's suggestion; ended up replacing ALL the on-card electrolytic and tantalum caps, and the problems went away.

Also check the cabling/connections to the VU overbridge (if you have one) - something may have come loose there.

Charles

Charles is correct. You should check +/- 15VDC especially when you have error message reported - all related to audio.

One of the first thing I would do with any A810 even with younger SN's greater than 5000 is to pull out the cards, remove the basis board from the back, replace all 470uF and 1000uF axial caps regardless. Even the blue Philips caps can go poof all of sudden and the dreaded yellow Frako caps have 100% failure rate.

The caps in the power regulator (Studer calls is stabilizer) board should be next for replacement.

Then, any machines with audio related issue, I would also suggest you remove the tape headblock and get to the repro head preamplifier board. There are two electrolytic caps for +/-15VDC supply for the opamp that need replacing.

Some of the logic problem even after all the caps replaced on basis board could be caused by a filter cap in the operating LED (LCD) panel for +5VDC. It should be replaced as well.

There are many other electrolytic caps needing replacements in cards but that's another story.

In addition, replacing the battery on the all Studer MPU card can go smoothly but after you pulled the old battery, you should examine the areas around the battery for any battery leaks that can corrode way the circuit traces. If the green stuff is anywhere on the chip socket, you must pull the socket out and examine the circuit traces and replace the chip socket(s). I have had the leaked battery chemical that had corroded the chip socket pins so badly, it dissolved metal pins completely away.