oh yes... another newbie pt-80 problem

[joem]

  so after two full days of amateur trouble shooting and endless hours trying to sort through the pt-80 search files i have done the lowest thing on earth and become a member of the forum. just kidding.


  so im a newbie to the forum, have built about four other pedals. anywho im getting a non-effected signal through the board and it appears unharmed. ive audio probed around not knowing where i should really be hearing no signal but

im getting audio out of the transistor (i used a 5089) which ive deemed as better than no audio.

probing around on the delay chip on pins 7 and 8 im getting a pretty distorted signal.

on the delay pins (cant remember which ones now) i was getting an effected signal but nothing to the sound of a delay, i just noticed that there were some pitch bends going on when i messed with the delay time knob.

like i said ive looked at other posts, specifically the ones where the problem where an unaffected signal was coming through with the delay on and i saw people posting voltage readings BUT.... to my dismay i could find nothing on if these were the correct voltages or not.  so i ask of you oh great pedal troubleshooters. is there a posting in the depths of this forum we are blessed with that tells me what i should be looking for? ive never done voltage readings on an ic before but could tell that i was doing them right when i tried, i just didnt know what exactly i was supposed to be getting.

btw im using a 15v dc 500ma power supply for the board. i know the layout from GGG asks for 18v but i also noticed people here were talking about a 15v minimum and i was planning on making the board to step up an average 9v but found out i had a 15v PS layin around which i wired for a normal jack.

hope this isnt too much, tia.

[geertjacobs]

There are two voltage regulators in the PT-80:
the 7812 is used to create 12 Volts.
the 7805 is used to create 5 Volts.
First check would be to see if they do their job.

[joem]

straight off the power jack of the PS voltage is at 20v

at the board im getting 19.1v

at the voltage refulators i am getting 11.9v-12v  and 5v. they are working.

[joem]

oh the subsitutions i forgot to mention.

http://generalguitargadgets.com/diagrams/pt80lo.gif

here they are noted off of the picture above.


bottom left of the board off of the 10k
.002uf was substituted with .0018uf

bottom left of the board off the other end of the 10k
.033uf was substituted with .034uf

bottom right of the pt2399 off of pin 16
.002 subbed with .0022uf

on each side of the tl072 off of the 1k's
.015uf's were subbed with .0147uf's

heres the thing. i have the assembled board sitting on a clean table with nothing under and since i dont have it in a box i havent wired the l.e.d. in yet. does this change anything not having the l.e.d. wired in as the layout on GGG shows?

[geertjacobs]

The substitutions are very close, so they shouldn't cause any problem.

If you look at the schematic, you'll see that the LED circuit (millenium bypass or variation) is unconnected if your circuit's output is connected to the output jack.(switch at output to "up") So led wiring shouldn't affect anything.

Pitch bends when messing with the delay time should indicate it's more or less working.
Are all your component values correct according to the schematic (e.g. no 100k resistor instead of 1k...)?

[joem]

just did my third check on the resistors and all is good except i just noticed that my xicon electrolytics are 20 percent tolerance.

btw im using the schematic with the millennium bypass removed.

[joem]

just did some probing around the compander

on pin 16 (off of the 22k resistor) im getting a faint signal of a muddy low passed sound of my original signal.

but im still quite bothered by the fuzzy distorted signal im getting on pins 7 and 8 off of my pt2399. can anyone explain this?