Comtac 2 Troubleshooting

I took a gamble and ordered a secondhand pair of Comtac 2's. Upon arrival they fired right up and noise amplification/reduction seemed to be working fine except the left ear seemed somewhat "weak". My novice brain thought the batteries may be running low so I changed them out and now the headset will not turn on. Tried several different sets of batteries with no success. Indentations on the battery cover indicates that the cover is coming into contact with the contact tabs on the headphones and potentially causing a disconnect. I've tried to power on without battery covers with no success.

Am I overlooking something obvious, is there some sort of chip reset code using volume buttons, or did these miraculously take a dump 30 minutes after I got them. Any help / insight would be appreciated.

Man.. sorry to hear (no pun intended) that. I've completely given up on Electronic ears. They are nothing but American Mediocrity trouble. I wish Toyota made everything I use.

Sample size of half dozen, the Sordin “Pros” have been absolutely GTG Mark.
I believe they’re made in Sweden, Eurotrash- so not ‘murican mediocrity.

I lost the speakers on my sordins about a year ago. They are about 7 years old. I opened them up for inspection and I had corrosion in the battery compartment that ruined the power wire from the terminal on the compartment to the board. If you open the wire jacket or can see the wire at the ends and it's tarnished or dull like an old penny generally it's no good. The copper needs to be shiny and bright.

I pulled the battery compartment apart to unsolder the wire, soldered a new wire into place and scraped the terminals clean and sealed it up with RTV. Works mint now. If it's already broken taking it apart can't really hurt, you may see something on the board/ wiring ect ect.

If I know I wont be using them for a while I pull the batteries out and I keep them under the velcro headband cover.

I think after a time ear sweat and old batteries can wreak havoc on the electronics.

I have Sordin MSA Pro-X and years ago I left some cheap batteries in them by accident. I scrubbed out all the crud I could. Did not disassemble.
Fast forward to now. Lately they would stop working. But I got so mixed up on batteries I wasn't sure what was going on. Normally I like to use Eneloop rechargeable batteries.
They don't last as long but I have a lot of them.

Sooo... after many WTF situations and almost ready to send in for service I sprayed some DeOxit D5 in the battery compartment. Gave it a good blast. Let it set for a day. Charged up two Eneloop Pro batteries.

Tested all functions.. GTG.
Turned on. Sat on table. They ran for the 4 hour timeout period. Restart. They ran for 24 hours +/- after 20 hours I am not sure exactly when they cut off. So call it 20+ hours on quality rechargeables. I think they rate at 40 hours for Alkaline.

IF.. you open them and all you see is battery crud. 99% alcohol scrub. DeOxit D5, which is good for all your electronics. Scratchy pots, etc.. Whatever you do. Be patient. Scrub it with alcohol. But let everything dry out for a day.

Your symptom, unless it's your ears, suggests a high resistance on the one channel that is low volume. That is not the problem I had. Mine were basically no battery life.

One other possible issue. Not familiar with your set but on the Sordins Pro models the input jack for the radio, mp3 player or whatever may turn off the active noise suppression. So you can hear the radio. the cups then just act as regular earcups. If that jack got oxidized it --could-- cause an imbalance or no suppression. So clean it also. Again 99% alcohol or DeOxit D5. Or possibly just plug a jack in and out a few times.

If you are going inside, scrubbing with alcohol and just a bit of DeOxit D5 on contact areas is highly unlikely to hurt anything. Just don't try to fire anything up for a day to be safe.

Two issues with your description:
1. They worked but left ear was weak....
2. Put in new batts and they didn't work at all....

Stop right there and put old batts in... is left ear still weak? I know you can't do that now.

Get two known good batts and be SURE you are inserting in proper orientation. On Sordin ProX it's easy to install backwards or parallel vs series.

https://srstactical.com/service scroll down a bit.