Lab Series L5 problems...

[J M Fahey]

If he joins and asks about something, he'll be treated with the utmost respect, like we all here.
FWIW *I* joined here looking for advice , which I got by the truckload with excellent results. :dbtu:

[Roly]

Yeah, and look at the mess you're in now!   :lmao:   

[Enzo]

I too am a crusty old mid 60s guy - on medicare and social security - and if I am anything it certainly is old school.   But I couldn;t imagine doing all this without the internet these days.   Imagine coming up with a Lab Series schematic without the internet today.

The last thing we would want to do would be get in his way if he feels he is making progress.   We won;t talk down to him.  What you have here is some old pros with serious experience and happy to share.

[Roly]

No InterWeb?  Well fust we wouldn't be trying to fix some amp on the other side of the planet by remote control, and if it was under our noses we'd be doing what we always did - seat of the pants.



"Yes, I know the engine has stopped ... "

[Enzo]

But as a commercial repair tech, the internet helps save me from ever having to say "Gee, I dunno, beats me, I have no schematics."  AT least the TV repair guys had Sams Photofacts.

[Roly]

I mainly did industrial electronics BI (Before Internet) and if there were circuits available at all they were generally in a language I didn't speak.  TV?  Half the machines I worked on I first had to figure out what they were supposed to do, then how they were supposed to do it, and finally why they weren't.

"What's it do?" I asked.
He looked astonished and said "How can you fix it if you don't know what it DOES?"
"If it works on known physical principles, you didn't import an alien technology from Alpha-Proxima, I can fix it."

I considered documentation of any sort a luxury.

[J M Fahey]

I considered documentation of any sort a luxury.

Er...., you don't live in Argentina, do you?  :lmao:

[Roly]

Real technicians don't need circuits, right JM?.

[J M Fahey]

Many times had to think so and go ahead, but the sure do help if available  :tu:

[dkjar]

Well.... after 4 months the amp is back.  It works now but now it has other issues. The compressor is still out, and if I turn the volume up much it starts to pop almost like a blown speaker.  I will do some more trouble shooting tomorrow to figure out if its pre or power amp issues.  Seems to be affected the most when I turn the frequency pot down all the way and the mid range up all the way.

[dkjar]

I plugged the guitar straight into the power amp and still got the sound so I assume that means it is post pre amp.  I made a recording.  Sounds pretty awful in mp3 (was amr) but you will definitely hear the issue.  The first part is just straight through on the second channel.  you can hear the repeated crackle/pop.  Then there is a pause as I plug directly into the poweramp and you can again hear the same problem.  Compressor on or off does not matter.

Anyone know where I should start?  I think it sounds like some others problems that have been on here so I am going back to read those old posts again.

[dkjar]

And.... it takes a little bit before it starts.  So something is warming up and then causing the issue I would assume.

[dkjar]

By a little bit I mean 1 minute or less.

[phatt]

Assuming all supply voltages are reading normal first,,,I'd be thinking of bypassing that compressor part (if possible) as that part seems to be an obvious suspect.
Phil.

[dkjar]

Bypass the compressor meaning more than just turning it off?