looking for someone to help me troubleshoot my ez1073

[ding]

I bulit an ez1073 and after some troubleshooting I got it working nicely but after moving it around a little rough it now doesnt any more.
http://groupdiy.com/index.php?topic=42457.msg719185#msg719185
I have no time to troubleshoot it now since I am trying to move my family to a new house and I am tired of looking at the inside of this thing dumbfounded. I only have a meter for testing. If someone would like to tell me what their rate is for email trouble shooting or preferably if you are in south florida I could just take the unit to you. I also have other electronic projects I want to start working on and this unit is just pissing me off. 

Thanks,
Alain

 

[weiss]

what do you mean by "moving it around a little rough" ?

 

[poctop]

I bulit an ez1073 and after some troubleshooting I got it working nicely but after moving it around a little rough it now doesnt any more.
http://groupdiy.com/index.php?topic=42457.msg719185#msg719185
I have no time to troubleshoot it now since I am trying to move my family to a new house and I am tired of looking at the inside of this thing dumbfounded. I only have a meter for testing. If someone would like to tell me what their rate is for email trouble shooting or preferably if you are in south florida I could just take the unit to you. I also have other electronic projects I want to start working on and this unit is just pissing me off. 

Thanks,
Alain

you could use the Voltage Chart that Martin have done on the thread and start measuring those voltages to start with ,
Best,
Dan,

 

[ding]

@weiss: I had the back of it propped up on a 1/4 inch piece of metal so I could plug the XLRs in and the back end slipped of and dropped about a 1/4 inch onto the table.

@dan: I have been using the voltage table from Martin. All voltages check out fine except for the output stage. Here is a recount of what is going on with it.

I'm really sad to say that I've run out of ideas troubleshooting this preamp. I have figured out what happens but I am not sure why. Here is the order of things.

1. Replace Q4
2. R26 starts at 95.5mv for 10 to 15 seconds
3. mv at R26 start rising until it reaches 328mv and stays there
4. If left turned on too long Q4 gets damaged.
5. Rinse and repeat.

All other voltages on all other transistors check out fine. I have replaced all three transistors on the output stage several times just to make sure. I replaced R23 for a 1 watt. Replaced R7 with 1 watt just in case. All resistors and caps test fine on the output stage. All resistors and caps are the correct value. Nothing is grounding that shouldn't be. Quadruple checked all solder joints with magnifier. Checked the 10k potentiometer R149.

I am not going to quit but I just don't know what else to do, what else to check, where to look next. I am really hoping someone can give me a clue as to what to check or test for. I am at a complete loss. I think I can draw out the output stage schematics with my eyes closed.  :'( If anyone has any ideas, no matter how strange they may sound, please let me know.

Thanks,
Alain

I am in my new house now but everything is in boxes so it will be a few weeks before I can get to it again. BTW I got your "walter white" and can't wait to start working on it.

Thanks everyone.