• Please note that there are a few updates and clarifications made in the Audiokarma Rules, mostly relating to advertising and the addition of the new "Paying it Forward" & "Giving back" forums in the AudioKarma Audio Marketplace section.

PROTON D-1200 CHANNEL OUT - ANY SUGGESTIONS ?

boatdrinks77

boatdrinks77

Well-Known Member
My Proton D-1200 power amp has a problem. When I first turn it on, the left channel does not work - no output and meter is dead. I have to turn the volume up kinda high and then the left channel will kick in and then it is fine - even at low volumes.

Last night I pulled the main relay out and cleaned the contacts hoping that might solve my issue, but it is doing the same thing.

Its not my preamp, I swapped it out with a different preamp and I have the same issue.

Any Ideas from you electronic experts out there ? Any suggestions would be greatly appreciated ! Dan :music:
 
Register to hide this ad
I defer to the Proton experts but I've generally heard the RCA input jacks are somewhat notorious for failing on this amplifier - either that or the solder connections to the board.
 
62caddy said:
I defer to the Proton experts but I've generally heard the RCA input jacks are somewhat notorious for failing on this amplifier - either that or the solder connections to the board.
Click to expand...

I replaced the RCA's the day I got the amp a few years ago....hmm, it has ALWAYS had this problem - maybe I did a bad soldier job. !!! I will check it today and I'll take some pics of the amp when I do.......Dan :music:
 
Symptom is not unlike that of a fractured/dry solder joint. May be visible with careful scrutiny using a loupe or magnifier.
 
Well of course now it has been running perfect since I started this post. F%&k ME !!! haha.

I was hoping to do a few tests while the channel was out --- like-- instead of turning the volume up to get the channel to kick in, I was going to let it set there at really low volume and see if the left channel started working after warming up. Also, just try touching components until the channel kicked in. (I have found many bad soldier joints with this method)

Anyhoo, Here is a pic of my amp ---- The guy who gave it to me put LEDs in it, so the Meters are REALLY bright !


009.JPG 008.JPG
 
Trebolo said:
I did a few months ago. Replaced caps in input circut and fixed, but could have been a cold solder joint somewhere that I fixed by accident, not sure!
Click to expand...


A recap is always good ! Hey is your amp the Bridgeable version ? Mine is not. I'd love to get two bridgeable versions and run them as mono's -- not because I want more power, just because it looks cool. haha
 
boatdrinks77 said:
A recap is always good ! Hey is your amp the Bridgeable version ? Mine is not. I'd love to get two bridgeable versions and run them as mono's -- not because I want more power, just because it looks cool. haha
Click to expand...
Yes mine is bridgeable. And I do have a bad habit of buying cool looking big amps with old school VU meters. I have almost every brand of vintage amps with big VU meters. Its a sickness, since I'm a artist (glass artist) I need visual stimuli as well as sound!!
 
avionic said:
Fouled protect relay contacts or cold solder connections
Click to expand...

I de-soldiered the relay last night and ran some 600 grit wet/dry sandpaper wet with De-Oxit between the contacts ..... The first time I fired it up, the left channel was out until I turned up the volume. Ever since then it has been working. Maybe I fixed it. I Don't know. I guess I just have to wait for it to act up again.... Dan :music:
 
just as an aside, I wouldn't use 600 although it's already done. I'd start with a business card soaked in D5; the most aggressive I've ever done is 2K grit paper on a Marantz 1070 that just wasn't passing a signal any other way. If you can replace the relay with current production that is really the correct fix although that's not always possible.
 
N8Nagel said:
just as an aside, I wouldn't use 600 although it's already done. I'd start with a business card soaked in D5; the most aggressive I've ever done is 2K grit paper on a Marantz 1070 that just wasn't passing a signal any other way. If you can replace the relay with current production that is really the correct fix although that's not always possible.
Click to expand...
I'd replace and not fart around with cleaning.
 
avionic said:
I'd replace and not fart around with cleaning.
Click to expand...

Yes if I had a relay, I would have replaced it ...... I just tore into it one night because I was tired of turning the damned thing on and only one channel working till I cranked up the volume.

If anyone has a replacement part number handy...............
 
Last edited:
N8Nagel said:
just as an aside, I wouldn't use 600 although it's already done. I'd start with a business card soaked in D5; the most aggressive I've ever done is 2K grit paper on a Marantz 1070 that just wasn't passing a signal any other way. If you can replace the relay with current production that is really the correct fix although that's not always possible.
Click to expand...


The contacts on that relay are pretty beefy, hitting them with 600 grit was not a big deal, believe me.

I was just chatting with fellow AK member Catrafter a few day ago on the phone about how I used to have some relay files and I lost them. that's what actually got me motivated to tear into the Proton......

I need to buy some new relay files....
 
Double check the footprint of your OEM relay. It looks like a LY2/HL2 footprint in the service manual.
 
You must log in or register to reply here.
Back
Top Bottom