is there a way to check the output transistors..ac voltage? if so what pin do i use?..thanks..ed

thanks jm! any idea why the volume drops after a few minutes.does it with  a guitar plugged into the return of the effects loop.does this mean it is in the power section of the amp?the volume comes back to full volume  sometimes then back down in volume again.the lights stopped working on the delay section of the amp and the delay and reverb stopped working after i did a factory reboot.pushing the a and d buttons and holding them upon startup.any ideas jump in.the delay and reverb did work before doing the reboot.i thought i might of goofed,but upon doing the factory reboot again ,it did the same thing..thanks....ed!!

just got the x-tronic 4000 hot air station.i removed a 28 pin small  surface mount ic (cs4221-ks) for my first time with no practice!awesome.i wasn't sure if it would speed up repairs!it will definitely be a huge improvement! it is awesome.i will let you know how it is for soldering in a couple of weeks when my obsolete chip comes in.really low price too.buy dirrect form mercantile station and save $10.00 over their e-bay price.....i did..the phone number there is ...402-742-2586.
this is a digital hot air and soldering gun unit!!!!!.later *****...ed!!!

p.s. no damage at all like my previous encounters removing surface mount ic's.fast and efficient....love it...

saying of the day: work smart not hard! let the tools do the work!!!!

measured voltages on regulators as folllows:
           u1 measures +8.2v
           u8 measures +5.0v  board reads +5v near regulator
          u26 measures +3.3v board reads +3.3 near regulator
          u27 measures +8.2v board reads +5v near regulator
          u29 measures +21.3v board reads +15v near regulator
          u31 measures -21.3v board reads -15v near regulator

          is something causing u29 and u31 to read high?possibly causing another chip to shut down? or is it normal?....thanks   ed!

does anyone have a schematic for this amp?i'm wondering where to start with my volume dropping off problem.has anyone else had a simular problem  that they have seen and what did you do to correct it?...thanks...ed

just purchased a hot air station.i'll get it soon.i will let everyone know if it helps in doing part replacements..$119.99.from a usa seller!.thanks...ed

what do you recommend for removing and replacing smd components .infared station?hot air station? or do you have a special technique you use.open for any ideas?if i buy something for making these repairs i'd like to make the right decision.thanks...ed

line 6 flextone lll amp.volume level drops after a short time of operation.seems to work great on initial startup then the volume drops off.any ideas.voltage regulator,output chip.also the delay lights went out.when i got the amp the delay worked and the volume dropped off.i did a factory reboot by holding down the a and d buttons on power up now the delay lights don't work and i still have the volume issue....thanks...ed

tried uploading the hartke gt60 schematic to ampix...sorry no luck....ed

replaced u3 ic and got the channels working
replaced
u1 ic
u10 ic
c12
c33
c35
the amp still hums.the channel switching stopped again.possibly a zener diode?
the amp seems to hum less when i get ther reverb tank farther away fro the output transistors and the transformer.the only problem is it is mounted in the cabinet right above the transformer.i thought i had it fixed till i reassembled it.i might of blown ic 3 again for the channel switching when i turned off a flourescent light as it was plugged into the same power strip. the channel switching is dead again.


any ideas welcome.i have the schematic ,but don't know how to upload it to the post as it says it is too large.unless i have to compress the file...helppp!...ed!

i replaced the tank with a good working tank and the amp still hums.i tested the rca leads with an ohm meter and all four leads test @ .2 ohms.do you have any other ideas...thanks for your help.if i ground the input tip to sleeve the hum goes away...if that helps.....thanks....ed!!

thanks again enzo.if you keep helping me out i'll soon know how to fix stuff in a professional way.i have the equipment,but knowledge is wisdom........thanks...ed!

thanks enzo for the extra tips.i have alot of circuit board that i can't get on the capcitors with anything as the solder terminals are on the underside if the board and the capacitors are tight to the top of the board.would be nice to test them with the board in place, then cut off the leads of the component and bend them straight up with a pair of pliers, so that the new component could be soldered to the wire legs sticking up.this would make it a repairmans dream.quick and easy....thanks again! i really respect your posts along with all the others that have helped me.i don't want to list their names here as i might forget one.i appreciate everyone that has helped me. i hope sometime i can help....thanks learning everday.....ed!!!

p.s.  enzo love to stop in to your shop in michigan and watch the whole trouble shooting process and possibly change a few components and help you out for a day as i learn form you.my sister lives in michigan and i go out to visit usually once a year every other year.... i'd love to,but i probably would get in your way!!thanks....ed!!

thanks fot the reply.i have tested capacitors with a esr meter.cap tester,oscilloscope ,and an ohm meter.i tested a bunch of capacitors in a rolland gr20 they all looked good with a capacitance meter and esr meter.i got a reply from j m fahey and he said to send a sine wave into the analog part of the circuit and trace back from the output till i found a good signal.i did this and found a bad cap that previously tested good with all the other ways.thats why i posted this topic.thanks for your help and concerns....ed!!

thanks for the idea about the longer leads.i was thinking i would have to buy a dual ac power supply or something as such.i am going to make some leads up right away.don't know why i didn't think of it. sorry about the caps. i have to break myself of a bad habit.thanks for answering my post and being so considerate about my capitals...i have a post about checking capacitors in the newbie section.could you help me with a how to proceedure on cap testing. electrolytics....thanks for all your help....ed!