Pearl PH-03 issue

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Pearl PH-03 issue

Postby andre23 » 21 May 2014, 23:07

I everybody, I'm new here, I've bought an old Phaser made by Pear in the '80s, sold as "not working", I have changed all the opas,chacked all the voltage, and also the MC14069, the LFO section seems work well but with the pedal engaged I can only heard the clean sound without the effected sound of the pedal.
I also removed the buffer with a 3dpdt for true bypass, so the MC14007 and all the other components from the buffer section are missing.
I took from "8" the out for true bypass.
Down here the schematic
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Re: Pearl PH-03 issue

Postby Blitz Krieg » 22 May 2014, 08:20

blown diodes in the power section?
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Re: Pearl PH-03 issue

Postby Fender3D » 22 May 2014, 09:46

Hi and welcome to the forum,

you should definitely hear a "phased" sound, cause the 4 stages will affect your signal when mixed with "dry" even when LFO or IC4 don't work...
so, check you're actually getting your output at C10. It might be a schematic error...

Otherwise check IC2 and/or IC3

Blitz Krieg wrote:blown diodes in the power section?


Why????
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Re: Pearl PH-03 issue

Postby tube-exorcist » 22 May 2014, 13:23

andre23 wrote:..... I have changed all the opas,......, and also the MC14069, ......

Unfortunately IC4 is NOT a MC4069.....
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Re: Pearl PH-03 issue

Postby andre23 » 22 May 2014, 16:27

@tube-exorcist
I'm pretty sure about IC4 because I removed the old one, it was a MC14069 by Motorola.
Before installing a new MC14069 I've tried other hex-inverter with no good result.
@Blizt Krieg
I will check the diodes but I think they work well 'cause all the pedal has a correct power supply.
@Fender3D
I can't heard any phased sound come out from the pedal, the IC2 and 3 work and I've taken the out from the C10
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Re: Pearl PH-03 issue

Postby tube-exorcist » 22 May 2014, 18:24

andre23 wrote:@tube-exorcist
I'm pretty sure about IC4 because I removed the old one, it was a MC14069 by Motorola.


Yes, that MC14069 maybe could have been inside because......:
andre23 wrote:....I've bought an old Phaser made by Pearl in the '80s, sold as "not working",.....

...... another "brilliant" solder jockey - maybe the seller - will have put it there.

This doesnt change anything on the fact, that IC4 is NOT (has NOT been) a MC14069 originally.

Have a look at the datasheet of the MC14069 and you will see that pin 7 of that chip goes to gnd and pin 14 to Vdd.

Image

When you have a look at the schematic you will see that Pin 7 of IC4 does NOT go to ground and PIN 14 does NOT go to Vdd. So it can´t be a MC14069.....
andre23 wrote:Before installing a new MC14069 I've tried other hex-inverter with no good result.

.... or another hex-inverter. It will be SOMETHING LIKE the (obsolete) AM79C11 or similar - a quad FET.
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Re: Pearl PH-03 issue

Postby Fender3D » 22 May 2014, 18:33

Lift C9:
does sound change?

If not, you have no signal into IC2 and/or IC3, because since you have 4 phase stages mixed at IC1a, you MUST hear some difference, modulated if LFO and IC4 work, static (phased) if they don't...

@tube

4069 is not used as inverter here.
If you don't connect power supply, you have access to mosfet and may use them as variable resistors... :wink:
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Re: Pearl PH-03 issue

Postby tube-exorcist » 22 May 2014, 19:18

Fender3D wrote:4069 is not used as inverter here.

If you don't connect power supply, you have access to mosfet and may use them as variable resistors... :wink:

Feel free to dream on about that there is a 4069 used here.
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Re: Pearl PH-03 issue

Postby Govmnt_Lacky » 23 May 2014, 00:09

All of the research I have done/seen points to IC4 being a 4069 :secret:
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Re: Pearl PH-03 issue

Postby lasermonkey » 23 May 2014, 02:02

It's a 4069 in mine! Like pretty much every pedal I have bought off ebay, mine wasn't working properly. When I looked at IC4 at an angle to the light, you could see that they had just gone over the top of the IC with a black permanent marker, but the writing was still legible. I swapped it for a new one and it worked fine.
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Re: Pearl PH-03 issue

Postby Dirk_Hendrik » 23 May 2014, 18:24

I do have some trouble contardicting Tube Excorcist on the device in question not being a 4069 since TE usuelly does not say something unless it's backed up with proper argumentation.
At the other hand I see a lot of suggestions the device is a 4069... :scratch:
Sorry. Plain out of planes.

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Re: Pearl PH-03 issue

Postby lasermonkey » 24 May 2014, 01:44

I can only imagine that there are two versions. Maybe the 4069 was revision 2, because the original IC became obsolete?
Just a thought.....
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Re: Pearl PH-03 issue

Postby Blitz Krieg » 26 May 2014, 11:13

tube-exorcist wrote:
andre23 wrote:@tube-exorcist
It will be SOMETHING LIKE the (obsolete) AM79C11 or similar - a quad FET.


otherwise what kind of phaser topology is it? It's not OTA based or LDR based.
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