Update: I have solved the locked infinite repeat issue, and that works as intended. The pedal works perfectly in 8 second mode. However, when I switch to 2 or 1/2, the effect doesn't work. When it kicks in, it basically doubles the signal overtop of the input, i.e. Just makes the sound a little ...

Here's a better quality copy of the PDS8k schematics, that musicparts.com document is truly wretched. Like, having it all f'ed up like they did it, it's almost worse than having no schematic at all 😤 My suggestion is to check the 4007 at U3, maybe try swapping a fresh one in there. Over the years I' ...

I have a 1980 long dash Boss OD-1 with the 4558. But I have a few issues with the pedal...I think. For one, the pedal doesn't work on a battery, yet the jack doesn't seem to be shunted. The LED never illuminates, even momentarily, yet the LED is tested and working fine. Also, the pedal just doesn't ...

I just repaired one of these with this exact fault. The optocoupler was faulty. I replaced it with two single generic VTL style optos (one on each side of the board) that roughly measured 5 or 6M dark. Needed to adjust TP1 for good level of intensity and TP3/4 for balance. These two trimpots (in ...

Was that the quad opamp with off-standard pinout? IIRC it was old but you could do a modern opamp on an adapter board to change the pinout (if there's room for it). Maybe a place like the electronic goldmine still has them? I can't find any NOS or pulled ICs anywhere. I still haven't found a proper ...

Anybody know of a pin-equivalent replacement for the IC1 in the vintage version of this pedal? 1, 2, & 3 have the numbers scraped, but I believe them to be RC4149s based on random schematics. According to the schematic, it could also be an XR4212 but based on anything I've found that's a 14 pin IC ...

GorillaHuman wrote: ↑22 Mar 2024, 19:12 Any ideas please?

I wish I could remember, but I really have no memory of what I did to fix it. I do n remember being somewhat perturbed because it was an easy fix.

I've got everything back to the original issue. Does anybody have a video of the pulsing incandescent with the cap off? I actually feel like my problem is the bulb not dimming enough...

But, just as well, I assumed your DRAM is de DIL18 version. Here's the datasheet: https://www.datasheets360.com/pdf/-5481007005091624953 Keyword is that it's a 1Megx1 device. By googling that one I ended up here: http://www.amiga-stuff.com/hardware/1mx1-dram.html Scroll below and see that the ...

For my understanding; All IC's but the memory were replaced but that did not fix the issue. I give you credits for not targeting at the most difficult to obtain part as being the prime suspect. That's a way more common approach ;-) What I miss in this thread are some basic verification measurements ...

APMT wrote: ↑14 Mar 2024, 15:42 I had a DigiTech PDS 1002 in a similar state and it didn't work until I replaced all of the CMOS chips.

I changed all the ICs but the 411024, although I can't guarantee they were good to begin with. I guess I should find a similar pedal to swap ICs into.

Anybody know where to get a replacement 411024 DRAM for U21, or suitable replacement? I've tried lots of things to get this pedal to work without success except replacing that IC.

Oh ok. So the LED in the photocoupler doesn't actually flash, just adjusts intensity. I'll have to check that transistor. I seem to be getting enough voltage to the bulb I would think, but the "phase" isn't strong enough. That is correct. The LED in the photocoupler just increases or decreases in ...

Oh ok. So the LED in the photocoupler doesn't actually flash, just adjusts intensity. I'll have to check that transistor. I seem to be getting enough voltage to the bulb I would think, but the "phase" isn't strong enough. That is correct. The LED in the photocoupler just increases or decreases in ...

I don't really understand this circuit. What is the point of having both the photocoupler and the LDR's with the incandescent? I've been chasing thinking the lamp being dim was the problem, but is it actually a fault with the photocoupler? In this version of the Uni-Vibe, the photocoupler replaces ...

I don't really understand this circuit. What is the point of having both the photocoupler and the LDR's with the incandescent? I've been chasing thinking the lamp being dim was the problem, but is it actually a fault with the photocoupler?

Oh geez...this is gonna be a tough one.

Anybody have a schematic for the Digitech PDS 8000? I have one that produces no effect and the infinite loop is locked on. I will at times get a digital squeal when the effect is engaged (and the infinite loop is too obviously) until I go back to bypass.

Bumping this thread. Got similar problem! Setting TP1 does not change the behavior of the depth knob. After measuring I got fed up, and I baldly replaced Q2, U4, U5, U6 and even U8. Shotgun approach.... But the issue remains the same! This circuit has got me baffled; not understanding why the ...

For continuity and to assist troubleshooting, here's a thread on this pedal: https://www.freestompboxes.org/viewtopic.php?t=9043 Various posts there include links to the layout, BOM, service manual and schematic. Below is Harald Sabro's redrawn schematic with his notes. I would suspect either the ...