Hi everyone, i'm quite new to all this great stuff and am by no means an electronics wiz !.
I've completed great mods on a Boss SD-1 and a TS-9, by trial and error and the use of a resistor/cap calculator!!
I have just found an Ibanez SD-9 and was considering what to try and mod when....... ooops i lost the clean bypassed signal totally !.
Distortion sound is fine though, have changed out the FET switch but that did'nt help!!.
Does anyone have a clue what it could be, using simple terms, thanks?.
If i can be of any help with the mods i've done, i'd be happy to return the favour, warm regards from the UK.
Well.....One option thats the most obvious to me........but TONS of work. Get a schematic, and test every component you can. If you need to test the IC use a defferent dual Opamp. some good ones are NE5532...(someone fill in rest here). Mind you that will be a lot of work. Also check for shorts with the continuity test on multimeter. If there is condction between ground and + then ur pedals skrewed, and needs a lot of trouble shooting as anything could have gone. Besides, You might want to mod your pedal now. Go out and buy sockets, use a file to grind them down, and socket everything that can be changed(diodes, ics, Caps, etc....)
LM 250+
It seems like if you are able to switch from the distortion to nothing, then the switching may be working, but the buffer is malfunctioning. That pedal uses half of it's dual OA to buffer the straight signal. I'd try the opamp 1st.
Good Luck & Happy Hunting
RDV
Many thanks for that RDV, i have a couple of NOS JRC 4558's so i'll pop one in and let you know, GOOD MAN ! :D
What do you get in bypass mode? If it's a lofi distorted rumble check the 47uF can next to the opamp, mine was leaky.
... or you could measure the DC voltages on the opamp and transistor pins in both bypass and non-bypass and just by inspection see what is not at the correct voltage level...
Just a thought.
Thanks BigMan, i get a very very low level distortion, like the bleed through you get sometimes on these units, but no clean decent level at all.
R.G, which op amp pins to which transistor?. . . . . sorry but i'm a bit of a novice, so its "early days" as far as testing goes !!! :?:
The board was full of "cold" and "cracked" solder points, so i've carefully re- soldered about 15 of them.
The "op-amp" swop did'nt help i'm afraid :-(