That rare DSL issue with volume drop

[diesect20022000]

It looks like it's the culprit as it's right in the red stage circuit from what i can (barely lol) see.Now, my eyes are REALLY bad but, that's the only VISIBLE sign of distress from what i can tell anyway. everything else looks clean as a whistle.

 

[jcmjmp]

It looks like it's the culprit as it's right in the red stage circuit from what i can (barely lol) see.Now, my eyes are REALLY bad but, that's the only VISIBLE sign of distress from what i can tell anyway. everything else looks clean as a whistle.

You lost me. What are you talking about?

 

[Buggs.Crosby]

You lost me. What are you talking about?

just think if your lost where that would place me?........Disect....what are you trying to point out in that pic?......that shot is no where near the LDR circuit

 

[diesect20022000]

just think if your lost where that would place me?........Disect....what are you trying to point out in that pic?......that shot is no where near the LDR circuit

there's a burn mark the size of a pinhole om 5W1KJ. it's right by the 3rd preamp tube that's all i know and as i said "it's in there from what i can see but, i don't know" which meant literally that it's right next to it but, i'm not sure what it means. I thought maybe that held some significance but, apparently not. it's a pretty small mark on it but, i thought maybe that had some bearing on the amps problem. I don't really know this circuit though as i have never worked on it. I'm new to troubleshooting amps anyway so i'm flying blind for the most part with exception to safety precautions. I know that's a blurry picture and i know that's not the LDR i just figured the pinhole may mean something. from a visual standpoint nothing else looks PHYSICALY damaged but, i know that doen't hold significance all the time. I was trying to find the optocouplers online but, i must have typed them incorrectly as nothing popped up at Marshall or anywhere else. Anyway thanks so much guys, i appreciate the help. I want to get in there again but, i can't while my daughter's home so i'll probably just have to take her in.On the upside though now i know how to drain the caps and i did the ground while that may not be a big deal it's a start. I've never done any mods before so it was nice to see how simple that really was.

 

[diesect20022000]

basicaly though i was pointing out the burn mark on 5W1KJ and asking if that meant anything to anyone with experience.

 

[jcmjmp]

That resistor is common to all channels. If it looks burned, replace it... but it could just be some ink.... Back to the LDR... You'll have to check that before we look at other stuff, ok? If not, get a tech to look at the amp and send him the info in that post I referred to.

 

[diesect20022000]

That resistor is common to all channels. If it looks burned, replace it... but it could just be some ink.... Back to the LDR... You'll have to check that before we look at other stuff, ok? If not, get a tech to look at the amp and send him the info in that post I referred to.

Okay thanks. Yeah i'm taking it in tomorrow. This guy's a pro and i'm a complete novice minus the safety precautions but, i'm very thankfull to you and buggs for helping me out. I think since i have all the pictures of all the boards now i'm going to get some comparisons after it's fixed to get some info from personaly. That way i have a visual rep of what was done. I would love to tackle it but,i'm not confident in my....lack of ability,lol and i have a rambunctious 3 year old and i'm way too paranoid to work with her here at all, i'd die if she got hurt. On the upside though, i found some great sounds in my other amps and i learned some useful tests and whatnot from you and how to do mods in the future. You are all a great bunch of people. I can't WAIT to get her going tho. i love my other amps but, she's my centerpice for sure!

oh and i have written down all the info you've given me as well as taken pictures of everything. He's a good tech too so he'll run me through what he found and did to it.Sorry i ramble man, you've been very patient with me though and i appreciate that. Hope your Halloween went well!

 

[diesect20022000]

here's the fun part. I looked up the schematics that were supposed to match my amp and they didn't QUITE match which was part of why i took it in, i thought i was missing something. Well, i wasn't, the schematics that were supposed to match my amp ARE WRONG. My tech pointed out the same thing and this was after confirming the "right schematic" with Marshall. so, though my amp says it's a first series board it's not entirely. But, she's working again so hopefuly it stays this way. if not i'll have to move on but, for now i'm content.