Mojo Vibe

lowell · 07-23-2008, 09:22 PM

Working on broken Mojo Vibe. The wrong power supply was plugged into this pedal and now it does not work. I believe there are some protection diodes in there and they are 1N5817 schottky diodes. These diodes are rated at forward voltage drop of .45-.75 depending on current. Could I replace these w/ a 1N400x type? I'm thinking this will work but what might the 1N400x type not do that the 1N5817 would do better?

lowell · 07-23-2008, 10:04 PM

anyone have a schem for this pedal? There is signal but no effect.

lowell · 07-23-2008, 10:30 PM

If no schem... anyone able to explain how the voltage converter op-amp works? (MAX1044 ). Or if these pin voltages seem good or bad?

All are DC volts:

1 9.56
2 7.29
3 0
4 .28
5 9.56
6 6.8-7.26
7 7.2
8 .28

cjlectronics · 07-24-2008, 01:57 PM

I fixed one a while back. The problem was the MAX1044 was not driving the lamp. The Max1044 is configured as a voltage doubler, so the lamp voltage should be 15v or higher. I never could find a schematic.

The 1N5817 schottky diodes turn on faster than the 1N400X series. I believe the purpose for using these is two fold. One, to protect against a reverse polarity power voltage and two, to suppress transient voltage spikes. They kill two birds with one stone where the 1N400X just protect against a reverse power source.

CJL

lowell · 07-24-2008, 06:04 PM

thanks for you help!

blubp · 07-13-2009, 08:47 PM

I seem to have the same problem with my Mojo Vibe. It seems to work fine most of the time, but sometimes gives off a squeaking noise ( varies with effect rate ). High rates also causes the lamp to get "stuck" at full effect, resulting in no modulation. I´ve found various models of the max1044 - do you know the exact part number of the component used?

I bought the Mojo second hand - I love it, but because I don´t live in the US, it would probably be cumbersome and expensive to send the effect back for repair.

Thanks!

cjlectronics · 07-14-2009, 01:34 PM

MAX1044CPA, the 8 pin DIP I think. Its been a while??

CJ

blubp · 07-16-2009, 12:13 PM

Thanks! That saved my day

blubp · 09-03-2009, 06:59 PM

Just wanted you to know that i ordered a replacement for the MAX1044CPA, fitted it, and sure enough - it took care of the problem. Mine was only partially broken - it would't drive the lamp at high rates.

07-23-2008, 09:22 PM	#1
lowell Senior Member Join Date: Jun 2007 Posts: 1,120	Mojo Vibe Working on broken Mojo Vibe. The wrong power supply was plugged into this pedal and now it does not work. I believe there are some protection diodes in there and they are 1N5817 schottky diodes. These diodes are rated at forward voltage drop of .45-.75 depending on current. Could I replace these w/ a 1N400x type? I'm thinking this will work but what might the 1N400x type not do that the 1N5817 would do better?

07-13-2009, 08:47 PM	#6
blubp Junior Member Join Date: Jul 2009 Posts: 3	Moo Vibe I seem to have the same problem with my Mojo Vibe. It seems to work fine most of the time, but sometimes gives off a squeaking noise ( varies with effect rate ). High rates also causes the lamp to get "stuck" at full effect, resulting in no modulation. I´ve found various models of the max1044 - do you know the exact part number of the component used? I bought the Mojo second hand - I love it, but because I don´t live in the US, it would probably be cumbersome and expensive to send the effect back for repair. Thanks!

09-03-2009, 06:59 PM	#9
blubp Junior Member Join Date: Jul 2009 Posts: 3	Max1044cpa Just wanted you to know that i ordered a replacement for the MAX1044CPA, fitted it, and sure enough - it took care of the problem. Mine was only partially broken - it would't drive the lamp at high rates.

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07-23-2008, 10:04 PM	#2
lowell Senior Member Join Date: Jun 2007 Posts: 1,120	anyone have a schem for this pedal? There is signal but no effect.

07-23-2008, 10:30 PM	#3
lowell Senior Member Join Date: Jun 2007 Posts: 1,120	If no schem... anyone able to explain how the voltage converter op-amp works? (MAX1044 ). Or if these pin voltages seem good or bad? All are DC volts: 1 9.56 2 7.29 3 0 4 .28 5 9.56 6 6.8-7.26 7 7.2 8 .28

07-24-2008, 01:57 PM	#4
cjlectronics Supporting Member Join Date: May 2006 Posts: 182	I fixed one a while back. The problem was the MAX1044 was not driving the lamp. The Max1044 is configured as a voltage doubler, so the lamp voltage should be 15v or higher. I never could find a schematic. The 1N5817 schottky diodes turn on faster than the 1N400X series. I believe the purpose for using these is two fold. One, to protect against a reverse polarity power voltage and two, to suppress transient voltage spikes. They kill two birds with one stone where the 1N400X just protect against a reverse power source. CJL

07-24-2008, 06:04 PM	#5
lowell Senior Member Join Date: Jun 2007 Posts: 1,120	thanks for you help!

07-14-2009, 01:34 PM	#7
cjlectronics Supporting Member Join Date: May 2006 Posts: 182	MAX1044CPA, the 8 pin DIP I think. Its been a while?? CJ

07-16-2009, 12:13 PM	#8
blubp Junior Member Join Date: Jul 2009 Posts: 3	Thanks! That saved my day

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