Tremolo Problem

[mcasey1]

I recently performed a perhaps overkill procedure of changing all the resistors in my Tr-2 Tremolo to metal film.  I plugged in, turned it on, and no tremolo effect was audible.  Also, as I turn the depth pot up, the volume decreases.  Perhaps it is a fried inline IC?  I did accidentally touch one of the 4 inline chips.  I have ordered replacement chips, but was wondering if it could be something else.  Any ideas on how to troubleshoot this particular effect for the problem?

[MikeH]

I'd check all of your soldering connections.  Make sure electrolytes are oriented correctly too.  I takes a bit more than a "touch" to fry an IC.  Everytime something of mine doesn't work I have the instant urge to go to the "It must be a damaged component because I know I soldered everything perfectly" state of mind.  But in the end it's always a bad solder/incorrect orientation/wrong spot/wrong component/solder bridge that's causing the problem.

[Harry]

Everytime something of mine doesn't work I have the instant urge to go to the "It must be a damaged component because I know I soldered everything perfectly" state of mind.  But in the end it's always a bad solder/incorrect orientation/wrong spot/wrong component/solder bridge that's causing the problem.

Haha, I know what you mean, but in my case it's usually a fried component! I'm always frying the hell out of parts.

[mcasey1]

All electrolytics properly oriented, no solder bridges, above decent joints.  No visible errors whatsoever.  Anyone able to tell me or send me a link on how to debug an effect?

[MikeH]

There's a sticky thread in this forum called "DEBUGGING- What to do when it doesn't work".  That will get you started.

[mcasey1]

First time I've ever done this.  It would be a great help if someone can make sense of this causeI can't (yet).


BOSS TR-2 VOLTAGES

Transistors

Q1
C=8.31
B=0.01
E=8.31

Q6
C=9.02
B=9.03
E=9.02

Q3
C=8.31
B=0.01
E=0.00

Q4
C=9.05
B=4.50
E=9.05

Q7
C=8.68
B=8.69
E=9.03

Q5
C=8.68
B=8.69
E=9.03

I.C.s

IC3
P1=8.54
P2=8.57
P3=9.00
P4=9.03
P5=8.97
P6=8.57
P7=8.57
P8=9.05

IC4
P1=8.58
P2=8.54
P3=9.00
P4=9.03
P5=8.70
P6=8.54
P7=8.69
P8=9/05

IC1
P1=8.99
P2=8.47
P3=9.03
P4=8.47
P5=9.03
P6=0.00
P7=8.94
P8=8.51
P9=8.52
P10=9.05

IC2
P1=8.49
P2=8.52
P3=8.99
P4=9.03
P5=9.00
P6=8.99
P7=8.99
P8=9.05

Diodes

D5
A=4.88
K=9.03

D2
A=0.01
K=4.43

D3
A=0.01
K=4.43

D1
A=0.00
K=9.05

D4
A=9.03
K=9.05

Thanks in advance.

[Barcode80]

i'm VERY novice, but based on my previous limited experience those Q voltages seem very skewed (except for q4). I don't think you should have close to source voltage at all pins of the tranny. i've never debugged a trem though.

[mcasey1]

Heres a shematic to accompany:

http://www.freeinfosociety.com/electronics/schematics/audio/bosstr2.pdf

[markm]

Are you certain that all the resistor values are correct?
I'm not sure what you were hoping to acheive with your mod?
Are these pedals overly noisey?
I'm not overly familiar with this pedal but, maybe double check the resistor values with a DMM before doing anything else.
Good Luck 

[MartyMart]

First rule of any "mod" process :
Plug in and check after every 1-2 part changes, then you KNOW it's one of the last two
that has caused the problem ..... after 30 !!!! 

The only "decent" mod for the TR-2 is a slight gain lift, as it "appears" to drop when engaged
and a speed mod to go from normal trem to "very silly speed" , sonicly there's no noise problem
that needs curing with a whole new set of resistors I'm afraid ....

MM.

[mcasey1]

Just was looking to increase fidelity in bass and clarityofsound.

[gez]

I haven't checked all of it.  But straight away Q4 is out.  Check source connection for Q4.  Reflow this trannie's joints.

[gez]

OK, it looks like you're missing a ground connection somewhere...or it's been shorted to V+.

[MartyMart]

OK, it looks like you're missing a ground connection somewhere...or it's been shorted to V+.

Gez is correct, with 9v pretty much everywhere, you've either mis-connected a part to 9v or
have a small solder blob across 9v and ground - this could be tiny, but will still make a connection !!
Get a small magnifying glass out and re-check all your work, a DMM is required too.

MM

[gez]

a DMM is required too.

Good advice.  Check the connection from the -ve wire of your battery/PSU (both) to the board with a DMM then check voltage from this ground connection (assuming it's ok) to all other ground traces. 

[MartyMart]

Just was looking to increase fidelity in bass and clarityofsound.

Once you get the problem solved, for more low end content, you probably only have to
chage two caps , input cap C8 from 0.047uf to perhaps 0.22uf and C1 from 0.027uf to
0.1uf should do it ( from a quick look at the posted schem ) I cant see any other caps in
the audio path that limit the low end, but there may be another ....

MM.