Midiverb ii issues?
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From: El Grillo on 23 Jul 2010 01:16 Hello, I'm an new electronic technician TRYING to grasp a hold of my troubleshooting skills. I have two Midiverb 2's on my bench currently. One I was able to repair by replaceing some bad Filter caps, but the other is still giving me all the indicator diodes are lit and the 2 digit screen is dead. I tested all caps with an ESR meter and all is good. Noticed one small decoupling cap looked funky and replaced, but no luck. (I'm also a bit unsure if I replaced with the right cap. I had a few 104 film caps in the shop). SO...I'm asking for a bit of help from you all, if willing. Any idea where I should be looking? Thanks in advice for any help you can send my way. nicholas
From: Arfa Daily on 23 Jul 2010 12:16 "El Grillo" <nradina(a)gmail.com> wrote in message news:0b3f8d3e-ce83-4a8d-a032-59a743522db2(a)k19g2000yqc.googlegroups.com... > Hello, > > I'm an new electronic technician TRYING to grasp a hold of my > troubleshooting skills. > I have two Midiverb 2's on my bench currently. > > One I was able to repair by replaceing some bad Filter caps, but the > other is still giving me all the indicator diodes are lit and the 2 > digit screen is dead. > > I tested all caps with an ESR meter and all is good. > Noticed one small decoupling cap looked funky and replaced, but no > luck. > (I'm also a bit unsure if I replaced with the right cap. I had a few > 104 film caps in the shop). > > SO...I'm asking for a bit of help from you all, if willing. > > Any idea where I should be looking? > > Thanks in advice for any help you can send my way. > > nicholas Supply rails all correct voltages and clean (check with digital voltmeter and 'scope) ? Processor chip receiving correct reset ? Processor clock running ? No user control jammed in 'operating' position ? Such things can cause a processor to 'loop forever' if it executes a bit of code during boot up, to check for button presses that are part of a diagnostic entry sequence, and the button that's being 'pressed' is not one that is being expected. Arfa
From: Meat Plow on 23 Jul 2010 12:33 On Fri, 23 Jul 2010 17:16:34 +0100, Arfa Daily wrote: > "El Grillo" <nradina(a)gmail.com> wrote in message > news:0b3f8d3e-ce83-4a8d- a032-59a743522db2(a)k19g2000yqc.googlegroups.com... >> Hello, >> >> I'm an new electronic technician TRYING to grasp a hold of my >> troubleshooting skills. >> I have two Midiverb 2's on my bench currently. >> >> One I was able to repair by replaceing some bad Filter caps, but the >> other is still giving me all the indicator diodes are lit and the 2 >> digit screen is dead. >> >> I tested all caps with an ESR meter and all is good. Noticed one small >> decoupling cap looked funky and replaced, but no luck. >> (I'm also a bit unsure if I replaced with the right cap. I had a few >> 104 film caps in the shop). >> >> SO...I'm asking for a bit of help from you all, if willing. >> >> Any idea where I should be looking? >> >> Thanks in advice for any help you can send my way. >> >> nicholas > > Supply rails all correct voltages and clean (check with digital > voltmeter and 'scope) ? Processor chip receiving correct reset ? > Processor clock running ? No user control jammed in 'operating' position > ? Such things can cause a processor to 'loop forever' if it executes a > bit of code during boot up, to check for button presses that are part of > a diagnostic entry sequence, and the button that's being 'pressed' is > not one that is being expected. > > Arfa All indicators lit but no numeric display? No processor bootstrap. I have a couple of those BTW. Nice units for sound reinforcement.
From: El Grillo on 25 Jul 2010 13:05 Thanks for your help Meat Plow, Any ideas what could casue the processor to not boot? Could this be a voltage issue maybe?? Tanks for your help! n On Jul 23, 12:33 pm, Meat Plow <mhyw...(a)yahoo.com> wrote: > On Fri, 23 Jul 2010 17:16:34 +0100, Arfa Daily wrote: > > "El Grillo" <nrad...(a)gmail.com> wrote in message > > news:0b3f8d3e-ce83-4a8d- > > a032-59a743522...(a)k19g2000yqc.googlegroups.com... > > > > > > >> Hello, > > >> I'm an new electronic technician TRYING to grasp a hold of my > >> troubleshooting skills. > >> I have twoMidiverb2's on my bench currently. > > >> One I was able to repair by replaceing some bad Filter caps, but the > >> other is still giving me all the indicator diodes are lit and the 2 > >> digit screen is dead. > > >> I tested all caps with an ESR meter and all is good. Noticed one small > >> decoupling cap looked funky and replaced, but no luck. > >> (I'm also a bit unsure if I replaced with the right cap. I had a few > >> 104 film caps in the shop). > > >> SO...I'm asking for a bit of help from you all, if willing. > > >> Any idea where I should be looking? > > >> Thanks in advice for any help you can send my way. > > >> nicholas > > > Supply rails all correct voltages and clean (check with digital > > voltmeter and 'scope) ? Processor chip receiving correct reset ? > > Processor clock running ? No user control jammed in 'operating' position > > ? Such things can cause a processor to 'loop forever' if it executes a > > bit of code during boot up, to check for button presses that are part of > > a diagnostic entry sequence, and the button that's being 'pressed' is > > not one that is being expected. > > > Arfa > > All indicators lit but no numeric display? No processor bootstrap. > > I have a couple of those BTW. Nice units for sound reinforcement.
From: El Grillo on 25 Jul 2010 13:06
Thanks Arfa- My next plan is to check the voltages. Without the schematic, I'm a bit fuzzy on where to check the voltages and what they should be. Do you have a method to track down the correct voltages?? Thanks again for your help! n On Jul 23, 12:16 pm, "Arfa Daily" <arfa.da...(a)ntlworld.com> wrote: > "El Grillo" <nrad...(a)gmail.com> wrote in message > > news:0b3f8d3e-ce83-4a8d-a032-59a743522db2(a)k19g2000yqc.googlegroups.com... > > > > > > > Hello, > > > I'm an new electronic technician TRYING to grasp a hold of my > > troubleshooting skills. > > I have twoMidiverb2's on my bench currently. > > > One I was able to repair by replaceing some bad Filter caps, but the > > other is still giving me all the indicator diodes are lit and the 2 > > digit screen is dead. > > > I tested all caps with an ESR meter and all is good. > > Noticed one small decoupling cap looked funky and replaced, but no > > luck. > > (I'm also a bit unsure if I replaced with the right cap. I had a few > > 104 film caps in the shop). > > > SO...I'm asking for a bit of help from you all, if willing. > > > Any idea where I should be looking? > > > Thanks in advice for any help you can send my way. > > > nicholas > > Supply rails all correct voltages and clean (check with digital voltmeter > and 'scope) ? Processor chip receiving correct reset ? Processor clock > running ? No user control jammed in 'operating' position ? Such things can > cause a processor to 'loop forever' if it executes a bit of code during boot > up, to check for button presses that are part of a diagnostic entry > sequence, and the button that's being 'pressed' is not one that is being > expected. > > Arfa |