Vintage Synth Repair

Hi...

New to the shop

Arp axxe 2310-631

OSC's are ok, Noise gen OK, S+H ok

VCF ..Not so much... VCF Freq and ADSR only want to "work" at Max excursion of sliders. In some situations , Release , on the envelope gen
WONT release.

I have a service manual.

I'm a virgin to this unit so, be gentle.

I don't have any schematics, but I would:
1) check PSU delivers all the required voltages. Adjust if necessary.
2) check the control voltages driving the VCF when all sliders down; you should find 0V. If not, check who delivers a voltage. Might be a blown tantalum, a common disease on ARP.

--- In vintagesynthrepair@yahoogroups.com, "Scott" <painintheamp@...> wrote:

>
> Hi...
> 
> New to the shop
> 
> Arp axxe 2310-631
> 
> OSC's are ok, Noise gen OK, S+H ok
> 
> VCF ..Not so much... VCF Freq and ADSR only want to "work" at Max excursion of sliders. In some situations , Release , on the envelope gen
> WONT release.
> 
> I have a service manual.
> 
> I'm a virgin to this unit so, be gentle.
>

I'll second #1 and #2 below, and add:
3) Be VERY suspicious of the sliders! Sliders on pretty much all the "named" (as opposed to numbered) ARP's will likely be exhibiting problems by this time.  The best way I've found to check for good operation of the sliders is with a signal tracer, such as the Heathkit IT-5283 (found on ebay most anytime, and can usually be had for only a few greens). Connect the tracer to the (unpowered) slider and move the slider back and forth as you listen to the tone on the tracer. If you get a smooth tone change over the slider travel, you're likely in good shape, but usually it'll be broken/choppy/intermittent. The sliders on most units have become so problematic 30 years from manufacture that "Dr. Phil" over at http://www.discretesynthesizers.com/ will only take in a unit for work if it includes a new (Lighted!) slider re-fit. How to clean/restore the original sliders?  Make sure you're sitting down and check out: http://www.youtube.com/watch?v=DwRlZyIG6rg -- and YES, the guy (Kevin Lightner) in the video (www.synthfool.com) is one of the best synth techs around and knows what he's doing! (No, I've never done this to any of my synths.)
---Kevin (not Lightner)


--- In vintagesynthrepair@yahoogroups.com, "alesisfusion8hd" <babouche369@...> wrote:

>
> I don't have any schematics, but I would:
> 1) check PSU delivers all the required voltages. Adjust if necessary.
> 2) check the control voltages driving the VCF when all sliders down; you should find 0V. If not, check who delivers a voltage. Might be a blown tantalum, a common disease on ARP.
> 
> --- In vintagesynthrepair@yahoogroups.com, "Scott" <painintheamp@> wrote:
> >
> > Hi...
> > 
> > New to the shop
> > 
> > Arp axxe 2310-631
> > 
> > OSC's are ok, Noise gen OK, S+H ok
> > 
> > VCF ..Not so much... VCF Freq and ADSR only want to "work" at Max excursion of sliders. In some situations , Release , on the envelope gen
> > WONT release.
> > 
> > I have a service manual.
> > 
> > I'm a virgin to this unit so, be gentle.
> >
>