Univibe \ NeoVibe question: Bulb not flashing

[greg]

Hello.

I have built the NeoVibe Univibe project from GEOFEX (on an excellent PCB from General Guitar Gadgets.

The unit worked well for about a year, then stopped. The bulb either burned out naturally or from a physical shock (or, perhaps, an electronic failure).

I have replaced the bulb and it is lighting up as it should, but it is not pulsating. Rotating the pot which controls the speed does not cause the lamp to flash at a higher rate - it is simply not flashing at all.

Does anyone know where to begin troubleshooting?

Thanks,

Greg

[R.G.]

You would start troubleshooting
Debugging: What to do when it doesn't work.

In particular, measuring all the DC voltages on the LFO/lamp driver. I think you'll find that the LFO is working OK, but the driver transistor is shorted, killed by the first light bulb shorting when it failed.

But that's a guess. The debugging procedure is much more definitive.

R.G.

Originally Posted by greg

Hello.

I have built the NeoVibe Univibe project from GEOFEX (on an excellent PCB from General Guitar Gadgets.

The unit worked well for about a year, then stopped. The bulb either burned out naturally or from a physical shock (or, perhaps, an electronic failure).

I have replaced the bulb and it is lighting up as it should, but it is not pulsating. Rotating the pot which controls the speed does not cause the lamp to flash at a higher rate - it is simply not flashing at all.

Does anyone know where to begin troubleshooting?

Thanks,

Greg

[greg]

Thanks for the response R.G.

I finally have some time to get back into this Univibe issue and will likely begin the "proper" troubleshooting process this weekend.

I do have an additional question or two for you (all)

1) I'd like to add a status LED to the project and am interested to see if I can find out how to make it pulsate in time with the speed (which would simply be cool) - better yet, if it could pulsate constantly - whether the effect is On or Off, that would be even better. It would be more useful as a visual guide of the rate before it is switched On (but then, of course, not useful as a effect On/Off indicator). I'm using a standard 3P3T bypass.

2) My wall wart has kicked the bucket. I believe that I bought it originally through Small Bear. While I am sure I can find something suitable, I'd rather get a known good unit for this (non-noisy, able to handle the current draw, etc). Can anyone make a recommendation?

Thanks in advance,
Greg

[johnorlitta]

greg,

Hi, my name is John Orlitta. I don't have an answer for both of your questions, but if you go to the B.Y.O.C. (Build Your Own Clone) website, you can check out the "Wah Wah/ Neovibe/MK11/Relic" thread, concerning adding an led to the Neovibe. Someone named lego4040 added an led, using a 3dpt stompswitch to do so.

I am building the Neovibe, and at first the bulb would glow, but I was never able to get the bulb to pulse. I was getting set to check the voltages, but when I plugged in the power supply I noticed that the bulb stopped glowing. I checked out the power supply and found it to be dead, and I believe that the power supply has done something to the components on the board or blew the bulb, because even with a new power supply, the bulb will not glow. I also noticed that the lamp driver transistor (Q13) gets really hot.

So, being that you have experience building the Neovibe, can I ask a few questions?

Q1: Is it normal for the lamp driver transistor to get very hot? What transistor did you use as the lamp driver transistor?

Q2: What was the cause of your lamp not functioning? Was it simply because the power supply was dead, or did the power supply kill something on the board when it failed?

I hope my info for the led was helpful, and I hope you don't mind answering my questions. Thank you- John