DA univibe fading away...suggestions?

[pinkjimiphoton]

got this in my inbox on facebook today:

    Terrance: Jimi i have a Dallas Arbiter Univibe that i have been using for years lately the chorus setting seems to loosing volume , there has alway a difference in volume between the Tremelo setting and the Chorus setting , its just lately it seems more pronounced .
    Any ideas ?
   

    Jimi Photon:  sounds to me like one or more of the caps in that circuit are going open...as the caps dry up, they stop passing signal, and eventually the circuit gets weaker and weaker until it fades away. i bet that's what's happening here. i have a minimoog a friend gave me with the exact same symptoms awaiting some bench time. i can probably fix that for you if you want to send it to me, i'll replace all the electros in it, that should take care of it for another 20-30 years. i will ask the gurus to chime in on this tho, and get back to you...
   

does that sound about right? should i take this on as a repair gig? the only thing i can think of is that the caps are going bad...but i have no experience with univibes, and very little with JFET based circuits, so advice appreciated!!

Write a comment...

[R.G.]

I don't think Dallas Arbiter made any "univibes". Could be, but I believe that all the "Univibe" pedals were made by Shin-ei, and sold by Shin-ei and Univox. Dunlop owns the trademark now.

Be that as it may, yes, I would first replace the electrolytics, remelt all the solder joints, being careful not to introduce shorts in doing so, and from there do any further debug.

Vintage Univibes often have problems with the lamp driver transistor degrading from the heat they generate.

[pinkjimiphoton]

thanks for the info, RG...

i'll ask him to ship it to me then...i thought all univoxes were shin-ei, too, maybe he's confused.

it'll be a pleasure and an honor to work on a venerable piece like this!!

just curious, but do you think the lamp may have burned out too?

[R.G.]

It's possible. I've only seen one lamp burned out, but several dead driver transistors, though.

[pinkjimiphoton]

ok, i'll look into it...i asked him about it, he says it's a dunlop reissue ...i'm like dallas arbiter?



hoping the reissues aren't SMT...if they are like some of the more recent wahs, i'm not touching it with a 10 foot pole.

[tiges_ tendres]

If its a Dunlop reissue there probably isn't even a bulb in it.

I replaced a broken pot on a friends Rotovibe, and there was no bulb to speak of, also no SMD.

[pinkjimiphoton]

thanks bro