Bods

Wow, I never heard anything about that. I'll have to ask around see if anyone here remembers that coming down.

By the way, Tiny, I've been instructed by my com nav counterparts to inform you, that you are the man :cool:

Thanks all for the help. We've been swamped with work here for the past few weeks, but we finally fixed this hf problem last night. We were told that the capacitor had checked good early on in our troubleshooting and never looked at it again... until last night. We got a new capacitor in there and voila. HF works. Go figure. So in conclusion, HF#2 no sidetone, rx ok: corrective action is replaced capacitor C20RB Thanks again!!!:D

Hey Tiny, thanks for all your ideas. I've been set on it being a tx aud line since the start, but still havn't found anything. We checked the dummy load, which checked good, but havn't tried it in CW yet. It's been tough to get a chance to work this bird. Com/Nav usually gets the short end of the stick when it comes to maintenance priority. You're close, it's a Blk 35 BS1 EC-130, Tail# 1595. We swapped the secure bypass relays already as well as all the secure components, which didn't do anything. I suppose we could check the plugs there too. Yes it has toggle switches at each station for the AITG radio. We did this the other day with no change, we're going to move on to the mission interphone system next (back end). Thanks again for your help.

Thanks for all the ideas guys. I havn't been able to work it the past couple days due to some other mx being done on the plane which limited the amout of troubleshooting we could accomplish. I'm off for the next week, which I have to say, I'm looking forward to very much. Havn't had a day off in a couple weeks. I'm turning over this writeup to my new years shift and passing along all of your recommendations. Hopefully a fresh set of eyes will help. When we do get a fix, I'll be sure to post it so that in the future if someone else has a similar writeup they can have something that could hopefully help. Once again, thanks for your help.

I had a stab power issue a few years back on a 63 model, ended up being the cannon plug jack at the pressure disconnect. Difficult to get to cause it's under the floor, have to go behind the co-pilot's c/b panel. Ours was litterally burnt and pins were shorting to eachother. If I was still back there I could look at the old log books and get you more info, sorry. Hope you make some progress.

We checked the #2 dummy load for this exact reason, but of course it checked good. I'll have to check the #1 as well, didn't think to check that one, thanks. Right now I'm ready to try just about anything. And yes, you are correct in assuming that we have longwires. Man I wish we didn't. It only went to depot for an iso (our iso dock was booked solid) and I dont believe they removed the masts, but I'm pretty sure that even if the screws were conductive on them, it wouldn't matter because the mast itself is mounted to the a/c skin. We inspected and reseated the lightning arrestor and found nothing wrong.

Man, I wish that was it. That would have made my life really easy. We checked that when we first got the problem. We've swapped around all the secure equipment as well.

Been working this for about a week now. Little background on it. The plane left for depot two months ago with no hf problems, nothing in the previous 4 months as well. It landed at depot with #2 hf coupler fault and no tune tone. Depot serviced the coupler and were able to clear the fault and get the tune tone back, but they weren't able to transmit, blamed it on atmospherics :confused:, and wrote it up for an in-flight check. It landed back here with the no transmit problem. It tunes just fine, breaks squelch, no faults in any freq range, receive is crystal clear, just no transmit and no sidetone. We've swapped or replaced r/t's, r/t mounts, couplers, interlock relays, #2 rf interlock relay, secure interlock relays, secure processors, secure rcu's, and control panels. This is a non scns a/c. We've checked the capacitor in the junction box, the dummy load at the coupler, the lightning arrestor, and numerous mic and tx aud lines between the interphone junction box, rt, and coupler. When listening in from another a/c, you can hear it break squelch, then there's a loud high pictched hum/feedback like noise, but very very faintly (like hearing test faint), you can hear the operator asking for an hf check. I'm at a loss for where to go with this. It's one of the stranger hf problems I've encountered. Any help would be much appreciated. -Bods