a little help with a ts 808

Started by whomeno, September 21, 2019, 09:51:01 PM

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whomeno

built a ts 808 from here http://tagboardeffects.blogspot.com/2012/02/ibanez-ts808.html.
I think I have a short some where that I can Not find.
I have source music at tip when not pluged in to it, when pluged in no source music.














here are my voltages base voltage 9.59
ic
1 4.77
2  4.89
3 4.77
4 0
5 4.82
6 4.82
7 4.82
8 9.59

Q1
C 9.59
B 4.54
E 0

Q2
C 9.59
B 3.80
E 3.33

Can anyone find my mistake please
Gear as of now
Gibson 2017 Les Paul Tribute T
Epiphone Les paul Special (upgraded)
Marshall DSL 20 Head
Peavy Valve king 20 W
2 X 12 Cabinet with celestion vintage 30 & celestion G12T-75
And a lot of pedals

whomeno

ok found the short. now have it in bypass but nothing when engaged.
Gear as of now
Gibson 2017 Les Paul Tribute T
Epiphone Les paul Special (upgraded)
Marshall DSL 20 Head
Peavy Valve king 20 W
2 X 12 Cabinet with celestion vintage 30 & celestion G12T-75
And a lot of pedals

willienillie

#2
Don't know what short you found, but in the pics you're missing a cut, in the upper left under the 1K resistor, just to the left of the 10k Q1 emitter resistor.  Make that cut and you should have about 3V on Q1e.

There might be more, but start with that and see what happens.

Edit:  I should say upper left in the 1st pic (upper right in the 2nd).

whomeno

the cut under the 1k resistor is there it is hard to see in pic
Gear as of now
Gibson 2017 Les Paul Tribute T
Epiphone Les paul Special (upgraded)
Marshall DSL 20 Head
Peavy Valve king 20 W
2 X 12 Cabinet with celestion vintage 30 & celestion G12T-75
And a lot of pedals

duck_arse

we can't see your bypass switch or your in/out jacks to check your wiring.
" I will say no more "

willienillie

Quote from: whomeno on September 22, 2019, 12:37:01 AM
the cut under the 1k resistor is there it is hard to see in pic

Okay, I see it now, I was looking at your second pic the wrong way around.  Do you still have 0V on Q1e?

whomeno

Gear as of now
Gibson 2017 Les Paul Tribute T
Epiphone Les paul Special (upgraded)
Marshall DSL 20 Head
Peavy Valve king 20 W
2 X 12 Cabinet with celestion vintage 30 & celestion G12T-75
And a lot of pedals

whomeno

I rechecked all off board wiring and it is good
It is now working in the bypass mode.
I get nothing when pedal is engaged
Gear as of now
Gibson 2017 Les Paul Tribute T
Epiphone Les paul Special (upgraded)
Marshall DSL 20 Head
Peavy Valve king 20 W
2 X 12 Cabinet with celestion vintage 30 & celestion G12T-75
And a lot of pedals

willienillie

Quote from: whomeno on September 22, 2019, 11:46:34 AM
Yes 0 volt on q1 e

Well I can't see it, but there must be something shorting Q1e to ground (potential).  Look for tiny shards of copper, little bits of solder, or stray hairs from the stranded wires.

anotherjim

Q1
C 9.59
B 4.54
E 0

Q1 somehow is very wrong -  it could be the wrong type or blown.
As it's an NPN transistor, to have 4.54v across the base-emitter junction means that junction is open circuit - or it could be a version that doesn't have the Base on the middle pin. 2N5088 with odd pinouts have been known to exist!
The best possibility is that Q1 Base pin isn't reliably connected to the board due to poor or missing solder (it connected when you probed the Base voltage but disconnected then you probed the Emitter).

willienillie

^ Yeah, Jim is right.  You can have 0V on Q1e because there is no current flowing through the 10k emitter resistor.

whomeno

Had to replace Q1. now have the right voltages
But now lost all signal in bypass mode. man I can not win on this one
Gear as of now
Gibson 2017 Les Paul Tribute T
Epiphone Les paul Special (upgraded)
Marshall DSL 20 Head
Peavy Valve king 20 W
2 X 12 Cabinet with celestion vintage 30 & celestion G12T-75
And a lot of pedals

whomeno

Gear as of now
Gibson 2017 Les Paul Tribute T
Epiphone Les paul Special (upgraded)
Marshall DSL 20 Head
Peavy Valve king 20 W
2 X 12 Cabinet with celestion vintage 30 & celestion G12T-75
And a lot of pedals

willienillie

If all your voltages are now correct but still no sound, it's time to audio probe.

whomeno

I did audio probe. Got sound on cable tip
But when plugged into Jack I loose it
Rechecked all off board wiring.  It all looks good
Some where I got a short and Can't seem to find it
Gear as of now
Gibson 2017 Les Paul Tribute T
Epiphone Les paul Special (upgraded)
Marshall DSL 20 Head
Peavy Valve king 20 W
2 X 12 Cabinet with celestion vintage 30 & celestion G12T-75
And a lot of pedals

willienillie

Quote from: whomeno on September 23, 2019, 06:38:42 PM
Got sound on cable tip
But when plugged into Jack I loose it

That sounds more like a miswired input jack or stomp switch, but we can't see those in the pics.  Do you have continuity between input jack tip and ground?  Any chance you got the jacks reversed, plugging guitar into the output jack?  Easy to do when looking at the pedal upside down.

whomeno

I will have to check that again when I get home
I'm at the hospital with my wife will let you know
What I find
Gear as of now
Gibson 2017 Les Paul Tribute T
Epiphone Les paul Special (upgraded)
Marshall DSL 20 Head
Peavy Valve king 20 W
2 X 12 Cabinet with celestion vintage 30 & celestion G12T-75
And a lot of pedals

whomeno

#17
ok I am back.
I now have audio in bypass mode. still no audio when pedal is engaged. Here is my findings
base volts is 9.59
IC
1-4.7
2-4.7
3-4.7
4-0
5-4.7
6-4.7
7-4.7
8-9.59

Q1
C-9.59
B-3.7
E-3.2

Q2
C-9.59
B-3.7
E-3.3
I did an audio probe.
Gain pot audio on 1-2-3
tone pot audio on 1-2-3
level pot audio on 3 only no audio on 1 or 2.
could this be another bad 2n3904?
Gear as of now
Gibson 2017 Les Paul Tribute T
Epiphone Les paul Special (upgraded)
Marshall DSL 20 Head
Peavy Valve king 20 W
2 X 12 Cabinet with celestion vintage 30 & celestion G12T-75
And a lot of pedals

willienillie

Quote from: whomeno on September 27, 2019, 12:40:52 PM
level pot audio on 3 only no audio on 1 or 2.

This would be normal IF the level pot was turned all the way down.  If not, then the either the pot is bad, or the signal is grounding out just downstream.

whomeno

Thanks Everyone
I did a newbie mistake. wired all pots backwards.
Gear as of now
Gibson 2017 Les Paul Tribute T
Epiphone Les paul Special (upgraded)
Marshall DSL 20 Head
Peavy Valve king 20 W
2 X 12 Cabinet with celestion vintage 30 & celestion G12T-75
And a lot of pedals