Author Topic: Digitech RV7 Schematic for power Needed  (Read 458 times)

AdrianM55

Digitech RV7 Schematic for power Needed
« on: February 04, 2021, 05:07:06 PM »
Hello

Iím trying to find a component that is suppose is been burned by previous owner.
Itís the c16. Itís weird because someone bridged it with c12 pad which caused one of diodes to overheat
Generaly fx doesnít power on and I hope that replacing this CAP might fix it but I need schematic if anyone have one to determine what element that c16 is.

Please let me know if anyone had such problem.

Thank you


j_flanders

Re: Digitech RV7 Schematic for power Needed
« Reply #1 on: February 04, 2021, 08:13:03 PM »
I have a working RV7. I can have a look inside or take a photo. If it's an unmarked cap it won't help much though.
I very much doubt you're ever going to find a schematic.

You can try and ask Tom Von Kramm (Tom Cram?) who was in charge of the 'product development and management of DigiTech/DOD' at Digitech.
I'm sure he knows the answer to all your (technical) Digitech questions but I don't know if he's allowed to answer them.
It never hurts to try.

You can find him at his new company:
https://www.spiralelectricfx.com/

Or on thegearpage:
https://www.thegearpage.net/board/index.php?members/tom-von-kramm.131605/
« Last Edit: February 04, 2021, 08:17:55 PM by j_flanders »

AdrianM55

Re: Digitech RV7 Schematic for power Needed
« Reply #2 on: February 05, 2021, 02:08:23 AM »
Thank you very much for answer. Iíve seen someone posting schematic for Killdry mod so I was hoping that there might be leaked one somewhere.
I definitely would like you to take a close up photo of that top power section if you could.

I will ask the man behind this glorious device if he remeber or maybe has access to parts legend.

j_flanders

Re: Digitech RV7 Schematic for power Needed
« Reply #3 on: February 06, 2021, 01:20:19 PM »
Here are some pictures.
Unfortunately it's an unmarked cap (unlike a lot of the other caps)




AdrianM55

Re: Digitech RV7 Schematic for power Needed
« Reply #4 on: February 07, 2021, 04:08:31 PM »
Thanks mate!

I will study it more. Would you be able to provide me some test readings with multimeter if I show you specifically where and what to do??

j_flanders

Re: Digitech RV7 Schematic for power Needed
« Reply #5 on: February 07, 2021, 05:28:21 PM »
Sure, no problem. :)
Have you tried with a battery?
« Last Edit: February 07, 2021, 05:29:59 PM by j_flanders »

AdrianM55

Re: Digitech RV7 Schematic for power Needed
« Reply #6 on: February 08, 2021, 02:53:22 PM »
Yes mate. I'm 99% sure its the power section problem as there's no power coming to relays at all.
Battery goes through DC circuit or something is wrong. I've tracked 4 components that can be bad. One schottky diode overheats when on DC power mode and while this is happening voltage jumps like mad but on the 0.5V - 1.4v region which pushes me towards faulty CAP. Unfortunately for me to get any parts it'll take few weeks (china supplier).

Could you check for me C22 on diode mode?
Im getting reading of 66(dunno if that's ohms?) while c64 and c11 are reading higher values but same values.

Could also Check dioded D11 and D5(this one is next to c22) and see what readings you're getting and also if you can read them when you switch polarity on probes?
For some reason i can read them two and I don't know if it's meant to be like that.

And now I will wait patiently :)

j_flanders

Re: Digitech RV7 Schematic for power Needed
« Reply #7 on: February 08, 2021, 05:19:10 PM »

Could you check for me C22 on diode mode?
Im getting reading of 66(dunno if that's ohms?) while c64 and c11 are reading higher values but same values.

Could also Check dioded D11 and D5(this one is next to c22) and see what readings you're getting and also if you can read them when you switch polarity on probes?

C22: 1320 and 630 (diode mode and reversed probes)

D2: 222 and 1897 (diode mode + reversed probes)
D11: 222 and 853 (diode mode + reversed probes)

I assume you meant D2 instead of D5 as there's a D2 next to C22 on my board.

I was guessing to find the components around the power input but it would be convenient if you give a slight hint on where to find the components next time. No picture needed. Just something like: bottom right, in the middle, ... :)
« Last Edit: February 08, 2021, 05:22:39 PM by j_flanders »

AdrianM55

Re: Digitech RV7 Schematic for power Needed
« Reply #8 on: February 09, 2021, 03:32:59 AM »
Thanks mate!
Yes I was looking for readings around that power input.
so my C22 reads : 065 both ways

D2: 205 and 667
D11: 204 and 740

I don't really know what are tolerances for these but c22 and his smaller brother look to be damaged as they read very low resistance. I don't want to unsolder them until i get replacement parts but I think it'll be trial and error if this pedal is fixable at all.
Ebay seller already lied to me saying that it wasn't modified but there was a jumper wire to replace 0 ohm  resistor next to power input. I'm divided between returning it and call it a loss or try to learn on it even if I get even but at least i'll know roughly how the power section works. Thoughts?

j_flanders

Re: Digitech RV7 Schematic for power Needed
« Reply #9 on: February 09, 2021, 06:10:09 AM »
I don't really know what are tolerances for these but c22 and his smaller brother look to be damaged as they read very low resistance.
Without a schematic you don't know if there's a low value resistor in parallel causing the low resistance value.
Without unsoldering at least one side you can't test on buzzer/diode mode if a capacitor in circuit is/has a short.

I don't want to unsolder them until i get replacement parts but I think it'll be trial and error if this pedal is fixable at all.
Looking at this board (smt doesn't always scare me) I don't think it would survive a 'trial and error' based approach for a long time.
You need a schematic of some kind, a clear diagnosis and a strategy to fix it. All much easier said than done.


Ebay seller already lied to me saying that it wasn't modified but there was a jumper wire to replace 0 ohm  resistor next to power input.
I'm divided between returning it and call it a loss or try to learn on it even if I get even but at least i'll know roughly how the power section works. Thoughts?
This pedal and its successor (Polara) haven been discontinued. Since then, prices on the used market have doubled and I wouldn't be surprised if they continue to climb for this specific Digitech pedal.
From that point of view it's most definitely worth to fix it.

If it were me, I'd take some hi-res pictures (on a tripod) and start tracing the power section and then come back here and ask the experts where and what I should probe and what voltages I should need to see in varous places.

duck_arse

Re: Digitech RV7 Schematic for power Needed
« Reply #10 on: February 09, 2021, 09:24:39 AM »
Yes mate. I'm 99% sure its the power section problem as there's no power coming to relays at all.
Battery goes through DC circuit or something is wrong. I've tracked 4 components that can be bad. One schottky diode overheats when on DC power mode and while this is happening voltage jumps like mad but on the 0.5V - 1.4v region which pushes me towards faulty CAP. Unfortunately for me to get any parts it'll take few weeks (china supplier).

Could you check for me C22 on diode mode?
Im getting reading of 66(dunno if that's ohms?) while c64 and c11 are reading higher values but same values.

Could also Check dioded D11 and D5(this one is next to c22) and see what readings you're getting and also if you can read them when you switch polarity on probes?
For some reason i can read them two and I don't know if it's meant to be like that.

And now I will wait patiently :)

I doubt I'll be any help, but here's my observations. those two caps you mentioned as missing - from my view, they were never fitted. this happens often, with some parts as options.

and your voltages. it behooves me to ask if you are 100% certain your supply is connected the correct polarity, as those low and jumping voltages suggest a reverse protection diode conducting and shutting down the power supply. if the board has been fiddled, perhaps the protection diode was blown and refitted wrong, in which case it would be backwards and conduction with the supply correctly connected.

these are all things to consider, when you don't have the bung device in front of you; straws close enough to clutch at.
"I think we're done here."

"rule #1 - don't paraphrase."

'redundant legs don't grease the skids'

AdrianM55

Re: Digitech RV7 Schematic for power Needed
« Reply #11 on: February 10, 2021, 02:05:16 AM »
I don't really know what are tolerances for these but c22 and his smaller brother look to be damaged as they read very low resistance.
Without a schematic you don't know if there's a low value resistor in parallel causing the low resistance value.
Without unsoldering at least one side you can't test on buzzer/diode mode if a capacitor in circuit is/has a short.

I don't want to unsolder them until i get replacement parts but I think it'll be trial and error if this pedal is fixable at all.
Looking at this board (smt doesn't always scare me) I don't think it would survive a 'trial and error' based approach for a long time.
You need a schematic of some kind, a clear diagnosis and a strategy to fix it. All much easier said than done.


Ebay seller already lied to me saying that it wasn't modified but there was a jumper wire to replace 0 ohm  resistor next to power input.
I'm divided between returning it and call it a loss or try to learn on it even if I get even but at least i'll know roughly how the power section works. Thoughts?
This pedal and its successor (Polara) haven been discontinued. Since then, prices on the used market have doubled and I wouldn't be surprised if they continue to climb for this specific Digitech pedal.
From that point of view it's most definitely worth to fix it.

If it were me, I'd take some hi-res pictures (on a tripod) and start tracing the power section and then come back here and ask the experts where and what I should probe and what voltages I should need to see in varous places.

I think that this pedal is a 1.2FW version which I read sounds duller. Its like the metal knob polara it sounds less trebly which in some circumstances doesn't necessary work well.

I paid a bad price for it to fix it at this stage. If someone haven't played with it I would've attempted to repair it but at this point i can buy working one in better condition for slightly more dough.

Yes mate. I'm 99% sure its the power section problem as there's no power coming to relays at all.
Battery goes through DC circuit or something is wrong. I've tracked 4 components that can be bad. One schottky diode overheats when on DC power mode and while this is happening voltage jumps like mad but on the 0.5V - 1.4v region which pushes me towards faulty CAP. Unfortunately for me to get any parts it'll take few weeks (china supplier).

Could you check for me C22 on diode mode?
Im getting reading of 66(dunno if that's ohms?) while c64 and c11 are reading higher values but same values.

Could also Check dioded D11 and D5(this one is next to c22) and see what readings you're getting and also if you can read them when you switch polarity on probes?
For some reason i can read them two and I don't know if it's meant to be like that.

And now I will wait patiently :)

I doubt I'll be any help, but here's my observations. those two caps you mentioned as missing - from my view, they were never fitted. this happens often, with some parts as options.

and your voltages. it behooves me to ask if you are 100% certain your supply is connected the correct polarity, as those low and jumping voltages suggest a reverse protection diode conducting and shutting down the power supply. if the board has been fiddled, perhaps the protection diode was blown and refitted wrong, in which case it would be backwards and conduction with the supply correctly connected.

these are all things to consider, when you don't have the bung device in front of you; straws close enough to clutch at.

I think you're right as these were the thoughts i had somewhere in my head. This spiking voltage was turning red light on in my head nut i couldn't figure out why is that so in all fairness you could be 99% right on that one.

I'm not sure what to do at this point maybe if seller partially refunded me like 40 quid i could do it but i doubt he will.