Maestro FSH-1 MAX1044 Issue

[nephsuperman]

I am building a maestro fsh-1 from the ustomp schematic and layout. When i turn the bugger on, the LED lights up as it should, but I get nothing.  I opened it up and turned it on to find that the MAX1044 charge pump its really freaking hot, I thought it might be in backwards, but its not.  I am afraid to plug it in now until i find the problem.  I have checked to make sure that all the wiring, pcb traces, and components are all in the right place.  I think it may be something to do with two of the tranistors. I replaced Q5 and Q6, the BF245As with two NTW133s.  The 2 pinout sticks out just like a normal half oval silicon. The problem with these two is that they are round and I may have put them in backwards. I don't believe so though.  I also have the trimpots cranked all the way.  Any suggestions? 

[rubix cube]

I had the same thing when I made the tonepad version, because I'd not checked the pinouts of the transistors.  I started again both times, and if | remember rightly, I had fried the MAX1044.  Oops. Third time I made sure and it worked.

[nephsuperman]

when i reversed the pinouts the two ntw133s, the pump did the same thing.  The initial schematic called for 2 CA3080Ts, which I replaced with 2 CA3080Es. That shouldnt be it, but could it be?

[Paul Perry (Frostwave)]

The initial schematic called for 2 CA3080Ts, which I replaced with 2 CA3080Es. That shouldnt be it, but could it be?

No, that can't be it.
Might be worth disconnecting the output of the charge pump temporarily, to see if it works OK on zero load.
I always try to build the PSU first in an effect & test it, because if there is a fault, it's easier (and probably cheaper!!) to fix it then, rather than later.

[nephsuperman]

Hey rubix and Paul, thanks for the information.  I always learn tidbits more everytime I go to the forum
Pardon me for my ineptitude.  Here is what my problem is now, I am not sure which pin on the max1044 is the output. On the layout it looks to me that it is the 5th pin or the 1st pin or is it both?  The schematic on ustomp does not include the max1044 chip in its charge pump area, so I have been just been comparing between the ustomp and tonepad versions.  After I know which pin(s) is/are the output, how should i test the PSU effectiveness?  This is all under the impression that I have not fried my MAX1044 yet.   Thanks again.

Here is the layout image from upstomp. 

[slacker]

Pin 1 of the Max1044 is connected to pin 8 which is 9 volts, so that is also 9 volts. Pin 5 is the -9 volt output.
To test it remove the 2 jumpers from pins 1 and 5, that will disconnect the chip from the rest of the circuit. Then measure the voltages, if you get the right voltages and the chip doesn't get hot then it's probably Ok and the problem is somewhere in the main circuit.
I don't see how putting any of the transistors in the wrong way could cause this, it's more likely that you've got a something shorted to ground some where.

[nephsuperman]

so does the 3rd pin go directly to ground?

[nephsuperman]

Good news first, after disconnecting the outputs, the chip does not heat up like crazy!

Ok, these are the voltages from each pin to ground that I read from the MAX1044.
1. -9.08      8. -9.08
2. -4.72      7. -6.71
3. 0            6. -4.55
4. -4.35      5. -4.20

I dont think these look right for the most part, however i don't know if this is what i should be testing either.  Each of the 220 uF caps read + 9 volts on each side. Is there something else that I should be testing?

[nephsuperman]

thanks for the info slacker. 

so pins 1 and eight should be measureing +9 and they are measureing -9 when compared to ground.  The other crazy thing is that pin 5 is only measuring - 4.2 volts when it should be reading -9 volts.  I am not going to assume that the ship is fried yet because it just doesn't seem to me that it is.  Are there any guesses as to why these things are occuring?   

[nephsuperman]

ok so I reconnected the jumper from pin 1 and plugged in the circuit.  I got the same readings across the max chip and it didnt get hot.  So I proceeded to put in the 5th pin jumper back in place, I plugged the pedal in with my fingertip on the plastic top of the chip, after about 20 seconds or so it started to get hot again so I unplugged it.  I am guessing that it is a short or some other problem in that portion of the circuit.  Should I quickly try to test anything within the circuit while its plugged in and then unplug after a few seconds?  any suggestions would be much appreciated.

[Paul Perry (Frostwave)]

  Should I quickly try to test anything within the circuit while its plugged in and then unplug after a few seconds?  any suggestions would be much appreciated.

I don't think there is much point trying to measure stuff while it is cooking.
When too much current is drawn by a circuit, it is almost always due to :
1 solder short
or 2. reversed chip

I usually move around the board with DMM set to continuity & look for things that SHOULDN'T be connected, but which ARE connected.

[ustompsteve]

were you able to find a short?

--steve

[nephsuperman]

nope, i am still looking.

[nephsuperman]

I tested the hell out of the traces before I started laying any components on it.  The reason I did that was because the toner transferred on pretty thick and in some places the pads were touching.  I just filed those sections down until those were removed.  I know i got all those taken care of.  With all the components in place, i found two or so leads where i get chirps of continuity, only very intermitent chirps of continuity.  Tonight, or in the next few days, I am going to take out the 220 caps and test them, I still suspect those since the leads that are chirping are those that connect to the 220s.  I have been pretty busy so I haven't gotten around to testing it yet.  I'll let you know what I find out.  If you have any other thoughts though, I would love to hear them.  Thanks.

[captntasty]

I had the same problem the first time around - used NTE133's and fried a couple of 1044's before figuring it out - the 133's (even accounting for twisting leads to match pinouts) did nothing but fry 1044's - I guess they just weren't compatible or had specs that were just too far off.  I switched to BF245a's and had no problems.  It kinda pissed me off because the NTE133's were listed as a match for 2N4303's... not so much.  The 133's weren't cheap and neither are 1044's! 

As a side note, I built the GGG version also and didn't have enough 245's so I searched the spec sheets and ended up putting J201's in...  they work just as well.

[zpyder]

1. -9.08      8. -9.08
2. -4.72      7. -6.71
3. 0            6. -4.55
4. -4.35      5. -4.20

If you're getting -9v at input (pins 1 & then something is definitely wrong.  Are you using an adapter or battery?  Make sure that your power supply is not reversed (ie make sure GND is GND and not +9v).  some adapters have the negative on the outside of the plug, some on the inside...

I recently started a thread concerning problems with a MAX1044 in an ABY pedal.  Turns out the MAX1044 can only take a maximum of +10v in, and inevitably I had used an adapter above that rating and fried my 1044.  When this happened I started getting way wrong voltages on the pin5 (output).  But I definitely have the thing running at POSITIVE voltage on pins 1 & 8.

If you have some protoboard and two electro caps you can set up a very simple test circuit for the MAX1044.  I could provide you a schematic, but it is located in the MAX1044 datasheet under (something like) Voltage Inverter with BOOST.

cheers
zpyder

[nephsuperman]

I had the same problem the first time around - used NTE133's and fried a couple of 1044's before figuring it out - the 133's (even accounting for twisting leads to match pinouts) did nothing but fry 1044's - I guess they just weren't compatible or had specs that were just too far off.  I switched to BF245a's and had no problems.  It kinda pissed me off because the NTE133's were listed as a match for 2N4303's... not so much.  The 133's weren't cheap and neither are 1044's! 

As a side note, I built the GGG version also and didn't have enough 245's so I searched the spec sheets and ended up putting J201's in...  they work just as well.

I am going to bet money that this is it, those 133 bastards.  <edit> i wish i knew a local place i could get one more 245a, don't really want to shell out 4 bucks for one.  this might have to wait until i get permission from the mrs to do another project. </edit> i'll let you know real soon.

[nephsuperman]

I had the same problem the first time around - used NTE133's and fried a couple of 1044's before figuring it out - the 133's (even accounting for twisting leads to match pinouts) did nothing but fry 1044's - I guess they just weren't compatible or had specs that were just too far off.  I switched to BF245a's and had no problems.  It kinda pissed me off because the NTE133's were listed as a match for 2N4303's... not so much.  The 133's weren't cheap and neither are 1044's! 

As a side note, I built the GGG version also and didn't have enough 245's so I searched the spec sheets and ended up putting J201's in...  they work just as well.

are the J201's a replacement for the 245As? If so, are they easier to find than the 245As?  Just trying figure out the easiest way to finish this guy.  How about a 2N3819?

thanks again.