Bulb/lfo functioning on Neovibe but No Wet signal (?)

[analog kid]

first thing , sorry to have to ask for help, this seems not to be a typical symptom that anyone's had w/ their neovibes.  I have had mine for awhile and in the midst of reboxing it something has happened and I'm hoping for someone to know exactly where I should look.
  The bulb is lit as normal, Depth/Rate controls affect the brightness and pulsing just as they should but however the effect  can only be heard as a ground (hum) when switched to or probing  vibrato (wet ) side.   
I had it set up w/o the vibrato option and no volume pot. Just a Wet /Dry  mix pot in place of the R35/36 resistors in the form of two resistors and a pot wired as a divider... middle lug used as effect output. And I do have the 100k from input to ground there. for ts'ing purposes reinstalled the spdt toggle.
  Either when turning the mix pot fully toward the wet side 'CW' ,  or w/ SPDT set to vibrato , you hear the lfo pulsing in the form of a nasty hum. Only difference is when set to Vibrato via toggle there is NO other signal passing! just the pulsing, and  bringing the wet(pulsing/hum)in by the mix pot SPDT set to chorus there IS still dry signal.     Hope I'm not complicating this or confusing wet/dry 
        So any help before going through all the voltages, etc.. will be greatly appreciated! I have had alot of broken traces on this old board but I can't seem to find any or bridges. It may be obvious to someone what/where it likely is , so why not ask.  THANKS

[R.G.]

It's not obvious to me at least.

If it were mine, I'd start recording voltages.

[analog kid]

  Here's my voltages if they might help point it out but I am guessing it's sometime of ground problem likely a simple one    However update on the previous description cause I did find Q10's B/C were shorted, It's now vibing absolutely perfect working properly in effect and bypass. Only problem is ,as the throb was coming thru as hum before ,it's now coming thru wet mixed properly BUT the previous "hum" still remains very much in the foreground.      I apprecitate you taking a look RG , or anyone for that matter.

Regulator
Vin - 19.3v
vout- 15.03v

Q1
C  2v
B  1.5v
E  1v
Q2
C  4.2v
B  2.1
E  1.6
Q3
C 11.3
B  4.3
E 3.6
Q4
C 15v
B 4.8
E  4.3
Q5
C 11.3
B  4.3
E  3.8
Q6
C  15
B  4.8
E  4.3
Q7
C 11.3
B   4.3
E   3.8
Q8
C 15v
B  4.8
E  4.3
Q9
C  11.3
B   4.3
E   3.8
Q10
C  15v
B   5.95
E   5.4v
Q11
C  18.8
B  8.2v
E 9-12.5v
Q12
C 18.8v
B  9-12.5v
E  8-13v
Driver tranny (39,04 all others 5088)
C 11.7- 13v
B  2.4-2.7
E  1.7-2v

Diodes 1 and 2
  both C/A junctions apprx same 8.5-12v fluct.

Bulb legs
pin 1 -  19.3v
pin 2 - 11.2-13v

[analog kid]

troubleshoot UPDATE:
     Ok , I thought I had found the problems when I searched some more to find a thread long ago where someone had a loud hum(didn't say with the lfo pulse or not) not present in bypass which It ended up being his power supply.
Worth a look as  I've used only one power supply for my neovibe all along never a problem. I hooked up two 9vlts (reg out vltg 14.75)  and I thought the hum was gone , only to find that It was just quieter with batts yet still there.
EDIT: ( I just tried comparing batt power wall wart again , this time making sure the 2x9vlts were fresh and  equaled  exactly the same +15v on Vout of the regulator/ This time surprisingly w/ both at 15v the hum that is extremely audible using the wall wart  is prettly much not there powered by the batteries!! )doesn't make much sense cause The power supply seems fine w/ other fx. I powered my Polyphase clone w/ it to check and dead quiet as always.    getting rid of the throbbing hum w/ power supply is all I need here and I'm in business and can start giving my  wah shell EASYVIBE a rest  and  As I'm not real sure about the current draw on univibe.

[analog kid]

sorry so many posts w/o response but I've been answering some of my own questions and can't resist posting 
  HEY RG!,  May I have possibly found the source of the problem w/ the power supply causing this hum , where it  has not before?
I found this  in an old thread :

If you use a DC power supply, you must choose whether to use an isolated DC power jack or not. Because of the rectifier bridge, you cannot use a nonisolated power jack and the on-board rectifier bridge at the same time. You must either use an isolated (plastic busing style) power jack or else remove the rectifier diodes from the board and connect + to +DC and - to -DC from the power jack. Using the rectifiers and a non-isolated power jack simultaneously will result in overloads on the wall wart and some release of smoke, as well as another string of questions here

Although I hadn't YET gotten the actual symptoms listed from it , it's obvioulsy NOT the right way to set up the power supply.  I didn't think anything of it but when I rehoused the 'vibe I switched the original Plastic socket out for a chrome non switching one due to some panel mounting issues and cool looks.  So since I"m using a DC wart supply , have the bridge rect. in AND a Non-Insulated power jack.. is it possibly what's been causing the hum?? and if so has it possibly harmed another (you know what i'm talking about 'cross'thread refererence ) of my power supplies??
   either way I'm sure I'll find out onmy own in the morning as I'll put the plastic jack back in but I wanted to point this out. and thank goodness for archives. funny thing was I actually remembered reading that when I first built mine! Memory Retention 
Mind you this still may not be my problem since my powersupply is a pos. tip so there woudn't be any pos on the sleeve of the jack mixing thru the chassis to ground here. IF that was the reason in the quote above? Still....

[R.G.]

I cannot tell a lie, AK. I love it when people work through problems on their own - and you're right on top of it. You're doing really good work and reasoning well about the problems!

It is almost certain that your non-insulated DC jack is the problem. What is happening is that the bridge rectifier (-) is connected to signal ground inside the box, and so is the incoming DC. It is likely that your incoming DC is not very well filtered, so there are current pulses going into the filter caps on the board, and those current pulses cause the hum you hear. It's worse when the lamp brightens because that's when the most current is being pulled.

You can verify this theory by pulling that DC jack out of the housing, wrapping electrical tape around it, and then just plugging the wall wart into it with it flying loose. The hum should be gone if this is the problem.

You can do any one of a number of things. Best is probably to insulate  your DC jack from the housing somehow. You can use a plastic insulated jack, but it won't look as great as the chrome one. You may be able to find nylon bushings to insulate it in a bigger hole in the housing. Wrapping electrical tap round the jack and then bolting it back in is not a good idea as tape will creep and cut, so the problem will come back. You need a solid isolator.

Otherwise, you could pull out the bridge rectifier and just connect your DC directly to the + output of where the bridge rectifier used to be, likewise the - to the minus of the old bridge rectifier. This will be much better, but may still have some hum because the current pulses are going through the case on their way to the board.

Try one of those and see if you don't get much better.

[analog kid]

thanks for the vote of confidence RG , means a ton coming from you.
I had actually already come to the idea to just pull the jack out of the housing counting on it eliminating the hum , and of course it did.  funny how it feels much better when you know you found a problem yourself  isn't it.
anyway that takes care of that. I did however , probably foolishly, install  a couple battery clips in my box (since it's a RACO they fit)  so that it CAN BE used w/o a supply. Which means if I wanna leave em in there I'll have to go to the plastic jack or remember to never plug in a ps and batts because my Chrome jacks don't have the extra 'push pin'.    Even though I saw somewhere where you said batteries might not last a few hrs if that in the vibe. I'd say this is true if the current draw is as high as I think at all. Since two fresh 9v is only at 18v and a believe a regulator needs apprx +2v to effectively regulate down. So on a 15v reg that would be 17v , and that would be only apprx 1/2v loss per battery     To theoretically not be powering the unit effectively,  Correct?     
Oh well at least it will hold the batteries and even a few hrs is enough for a gig where you may not be able to get a powersupply or be able to find and extra plug it in.    Nooo that doesn't happen!  who knows they may last longer than theory suggest.  It seems I tried out two slightly over 8v batts to TS the hum and it was vibing, so maybe that blows the regulator theory?

[R.G.]

In this case it's the ampere-hour capacity of the batteries.

A common 9V battery stores something less than 450ma-hr of current before it's drained. That's a vast oversimplification of the process, but it works if you're not trying to predict exactly when the battery will go out.


I've never measured a vibe, but it's probably up there in the 50-75ma range because it has lots of discrete stages and it pulses that light bulb. At a first guess, if it's 50ma, then you'd get maybe 9 hours. If it's 75ma, a bit over 6 hours. If I guessed low, less than six hours.