Feeler: an "Eee-Zzz" christmas present...ez1073 and ez1073-500

[saxmonster]

are you sure you have the xlr hooks ups right?  from the pcb to the xlr sockets on the case.  Do you have the same wiring on each unit?  Just trying to think of things I have done in the past.

I don't think the stop pin would affect it  that would allow you to turn it past the writing on the front panel.

 

[ding]

I get 360mV at R26 and nothing happens when adjusting R20.

New Year and I finally got everything together enough at my new place to start fiddling with DIY again.

@KJ
I am having similar issues with R26 going up to 360mV, the Q4 transistor starts to get really hot. I went all out and replaced all of the transistors (checking each one carefully) just in case but that did not fix the problem. All of my other transistor voltages measure correctly. I have measure carefully around the output stage and everything seems to be soldered correctly. I even rigged Q3 and Q4 to be easily replaceable but haven't found what the problem is yet. Here is an image of my output stage. I'm kind of out of ideas and there is no tech in my area that can help me. I would love to get this working.

Anyone have any ideas or similar problems????

 

[Spadehead]

Hi All,

I have just finished my ez1073 1U build and all seemed to go well but I can't power the unit - I keep blowing fuses.

Anyone who had similar experiences - what are the first things to look for?

My build was a bit of a squeeze into the Collective cases unit - to the extent where when the unit is all connected up the bottom plate bows quite a bit - I also couldn't get a standoff under the front right of the PCb near the mic gain - not sure if this is an issue? the unit is on standoffs apart from that one so hopefully nothing is shorting underneath.....

I am using standard 100mA slow-blow fuses from Maplin in the UK and have followed the build diagrams religiously. A picture of my build up to now is attached. Any help anyone??? Eager to get this unit powered up.... ;0)

Spadehead

 

[Spadehead]

God help me - I think my blood sugar is low - making silly mistakes but I think I figured it - wired the power switch up wrong. Doh!!!

 

[Spadehead]

Okay so the unit is working -  calibration worked a treat first time. Just goes to show that one silly mistake can cause a headache.

Problems aren't over though. I'm getting nothing on the Mic input. Nada.

Line input works fine, as does the EQ - everything working as it should but no Mic signals. Thoughts anyone???

Spadehead

 

[saxmonster]

Double check your connections from the pcb to the xlr connection.  I had an issue with that where the molex wasn't touching properly.  Good luck.

 

[Spadehead]

Double check your connections from the pcb to the xlr connection.  I had an issue with that where the molex wasn't touching properly.  Good luck.

Thanks for that - I have just checked the soldering - I am going to the PCB direct without the molex headers - can't stand those things! All seems good. Must be a fault somewhere else....

 

[Spadehead]

Minor update. I can get a very faint signal with dynamic or condenser but only when mic gain is at +70 and trim is up all the way. At this point the noise is louder than the signal!!

Seems that 48v is working but almost non-existent mic signal. I have gone over all the soldering on components and switches in the mic section. Any ideas anyone??

 

[Spadehead]

Anyone?

 

[mickdundee63]

Minor update. I can get a very faint signal with dynamic or condenser but only when mic gain is at +70 and trim is up all the way. At this point the noise is louder than the signal!!

Seems that 48v is working but almost non-existent mic signal. I have gone over all the soldering on components and switches in the mic section. Any ideas anyone??

I am having a similar problem - line level Ok but mic input very very low. Weird thing is I know this unit was working a couple of months ago and I have just pulled it out again and having the problem. I have a second unit I know is working fine so when I get it back later today I'm going to do some continuity and voltage comparisons to see if I can figure this out.

 

[mickdundee63]

OK i figured  my error, it was the mic gain switch. I had not soldered in the first deck pole pin. It must have been leaning against the pad when I first fired it up. I see you said that you checked all the switches so this might not be your issue but thought I'd let you know.

 

[Spadehead]

Thanks Mick, I'll take another look. I also read a few pages back to check Dc volts between B and E on the transistors so I'm going to take a look at that today as well. Fingers crossed, thanks for the reply.

 

[Spadehead]

Okay so I have removed the PCB again, taken off the front plate and checked all transistors between B & E and all check in at around the 0.6V mark. Switches seem to be soldered ok - still no mic signal and running out of ideas. How would I check the mic transformer or is that not a likely culprit?

Anyone with some more suggestions of things to check?

Spadehead

 

[Spadehead]

Anyone have listed voltages for the schematic? I'm trying to track down issues and this would probably help!

 

[porkyman]

Okay so I have removed the PCB again, taken off the front plate and checked all transistors between B & E and all check in at around the 0.6V mark. Switches seem to be soldered ok - still no mic signal and running out of ideas. How would I check the mic transformer or is that not a likely culprit?

Anyone with some more suggestions of things to check?

Spadehead

have you checked phantom power. my switch seems backwards. up is off down is on.

 

[Spadehead]

have you checked phantom power. my switch seems backwards. up is off down is on.
[/quote]

Thanks for that but I think that's the way it's supposed to be - mine's the same at any rate.

Just a follow up on my unit for anyone that's interested or maybe having the same issues - my unit is now fixed and working correctly.

I was getting a clean Line input and the EQ was all working correctly so that narrowed down the search area considerably - thanks to Colin as well - a quick phone call and some advice on trace checking helped no end.

I had some bad soldering on the mic transformer - around the sil headers and trying to remove all this from the board led to me essentially wrecking the unit so I decided to start again with a new 9045. I got the small PCBs cleaned nicely so could put them on the new transformer and get it neater.

I was also losing the trace at c28, the small ceramic right by the mic transformer and one of the first places the signal goes after the input. Once this was swapped out for a new one and the input transformer was put back neater then the signal came through clear and strong!

Happy days!

 

[toobnoob]

Up for Off is pretty British. My Trace Elliot Amp is the same way

8)

 

[leitrim_lad]

Hey everyone.. Im wondering if anyone would be able to give me a dig out.

Ive built 2 of these units. Both units are working away, 1 unit is perfect but one unit seems to be 4db louder.

Ive tried every test i can think of.. running signals through etc. Ive also brought it into a tech in a local electricial store but to no avail.

Ive attached 3 pics of the unit and just thought maybe if anyone had any time to take a look a fresh eye might notice something we missed..

I would really appreciate it if anyone had the time to look as it driving me mad having these beautiful units sitting in the rack and not been able to use them as a stereo pair..

Thanks in advance

L

 

[leitrim_lad]

Pic 2

 

[leitrim_lad]

Pic 3