Modified SD-1 circuit help. Not working

Started by Strat68okc, June 15, 2013, 06:09:27 PM

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Strat68okc

I built this that I got from IVIark's site. Its verified, So I dunno where I've screwed it up but.. I seem to have managed to do so. I built it with the Cuervo mods from Wampler's Modding book.
The added numbers are what I THINK are the correct components from Brian's book. And the original schematic. I may wind up going back to the values on the layout just to get it working...

These are the things I did and changed. There was one cap I didn't have, the 27nf one. I used a .022uf



Here are pics of my vero board, and the switch and clipping boards I added.

Battery measured 9.05v I had 8.88v at the 9V in wire.
I used 2N5088 for Q1 and Q2. I checked the pinout on the date sheet. They are in correctly as far as I can tell.

Any help would be appreciated.
Q1
C=8.88v
B=0v
E=8.10v

Q2
C=8.88v
B=2.30v
E=3.56v

IC1 is a JRC4558 I checked the pinout on this one as well. Looks right.
1=8.26v
2=8.26v
3=7.65v
4=8.17v
5=8.21v
6=8.19v
7=8.29v
8=8.88v

D4
A=8.27v
K=7.94v

On the switch and the two little daughter boards,
A=8.26v
K=8.26v

All the diodes on those boards measure really close, 8.15v to 8.26v on either side. Cathode or anode.



oskar

It looks like you took the voltages without a plug in the input.

Strat68okc

No. There is a plug in both in and out. Its sitting here on my bench, untouched since last night. But maybe my input wiring is where the problem is. Thanks.

oskar

The voltages are off because there is no connection to ground/battery(-). First, check the off-board wiring. Second, that pink cable from the IC to ground looks like a good candidate to look up.

Strat68okc

Okay. I re-re-re-flowed all the solder joints. Checked all the wires, took a couple off and re-soldered them. Checked all the caps. Followed the circuit on my printed out copy of the layout. I twisted on the board a little.. finally, I had turned it sideways and was poking near the Drive 1 pot location and it fired up! Then it stopped. Now it won't. I touch various parts of the board and I can get reall buzzy sound out of it... I dunno.

oskar

Quote from: Strat68okc on June 16, 2013, 06:08:32 PM
Checked all the wires, took a couple off and re-soldered them...
One way to go is: Put the DVM in "Beep Mode" and test continuity from the leg of one component to the leg of another component in the same net you want to test.

Quote...it fired up! Then it stopped.
What does "fired up!" mean? Could you actually play through it for a while?

Can you post a link to a schematic your using?

I don't think anything around the drive pot can make it just come alive when the voltages in general are that off. Could be that the heating up of the board from your soldering made the metal expand enough to close one (or more) shorts temporarily. Start from battery minus pole and make sure there is a connection to anything that is supposed to be grounded.

Strat68okc

It would sort of work. It would sound ok, but not much overdrive, then as I played a few seconds, it would get buzzier and buzzier, like a dying battery. Checked the battery, put in a new one since mine was at 7 volts. Same thing. If it had my hand on the input transistor, it would play, but again, not much od at all. If I let go, it faded out to buzzy again.  I noticed that the emittor leg on the input buffer was broken. I replaced the socket, since I couldn't get the leg out, and trimmed the other legs. Nothing. It no longer worked no matter where I touched.

My DMM doesn't beep. It is El Cheapo.

Anyway ,I re-wired the ground. Checked and re-checked the solder joints, then I got tired of it and went to bed. All I have is the layout. The schematic is http://www.hobby-hour.com/electronics/s/sd1-super-overdrive.php. That one was the cleanest one I could find. There was another one I had seen and its possible the layout was drawn from it as it has the buffers and switch section marked. I can't seem to find it now.

mistahead

No beep mode?

Set it to measure the resistance, drop it to the lowest band and put it in your peripheral vision.

Each time you have continuity the numbers will jump in your peripheral - visual beeps as you don't need to read the numbers to check continuity.

I have the same cheap MM lol, I knocked up a continuity tester from an old PC buzzer and some probe taped to a couple of batteries in a clip-box - but frankly I just use the MM still.