Rocktron Intellifex Rack Mount Effects Processor - No Effect?

[Supernaut]

Hello everyone.

I recently purchased a Rocktron Intellifex effects processor which was sold as spares or repair, im a vehicle mechanic to trade and i just got into electronics repair as a hobby last year. I mostly buy 70's/80's guitar amplifiers and effects pedals as spares or repair and i have a fairly high success rate with regards to fixing them. With that said, this new unit that ive purchased is a bit beyond my skill set, i was hoping people might be able to toss out some loose idea's as to what i should test or check to try diagnose the fault.

I emailed the company support for a schematic and some insight as to what might be wrong, they sent me the schematic but unfortunately didn't give me any advice with regards to my fault. As it stands, i have done no work at all to this unit, just probed around with the multi meter. Il try list some relevant info below,

- The item was sold as spares or repair, the seller told me the unit passes a dry signal through it but the effects are never applied, i have tried this myself and i can confirm this is true, from a control standpoint, the unit seems fully functional. I can dive in and out of menu's, move the rotary selectors to different settings etc, but it never applies any effects.

- I have tried a factory reset of the unit which is described in the user manual, this had no impact on its current condition.

- Some voltage measurements i took would not sit still, one of the diodes likes to swing between 31.90vdc to roughly 32.90vdc, similar movement in voltage can be observed on other some components.

- Ive noticed someone has re-flowed some solder joints from the component side of the PCB but the trace side looks untouched, two screws were missing from the casing so its safe to say someone has been in before although i don't think any components have been replaced.

- The tops of some electrolytic caps have positive voltage on them, 800mv in some instances, as far as i understand (although i might be wrong?) negative voltage can be measured from the top of an electrolytic but not positive voltage? Worth noting that negative value electrolytics will drain slightly when i keep my positive multi meter lead on the top of the cap and the negative lead to chassis ground.

- Theres nothing burned or physically damaged from what i can see, the fuse is also intact and potentially looks original. The unit takes 9vac for operation. The unit dates back to the last 90's and is made in the USA. I think the retail on these units was quite high when first released so its not a cheapo device.

-Input and Output level pots work as intended, no crackles or pops when operated.

- Testing conditions are as follows: Guitar to Rocktron Intellifex to Amplifier. Multi meter black lead connected to chassis ground, using 60VDC range on the meter.

Anyway, heres the schematic info i was sent today and also a picture of the inside of the unit. All i have is a UNI-T UT89X multi meter, no scope or anything like that.


Any insight would be appreciated,
Thanks.

[_rushin_or_draggin_]

I had a behringer mixer with built in effects that woundn’t work due to the filter caps in the PSU going bad. I would get a dry signal through but no effects. Of course your unit is quite a bit more complex than my mixer but I would definitely check that. Electrolytics are cheap enough and if you have some basic soldering knowledge, might not bad a bad thing to practice on.