NEW SAD1024 - Clone Theory FIXED! Now the trimpots?????????

[Kleber AG]

I'm starting it again as now I got the original EH schem with the SAD1024 BBD
Thanks to Steve Daniels (Small Bear Elec) who got this schem from Sovtech(I think), and he asked if it could be posted for everyone and it's OK to post, so here it is:  
http://www.geocities.com/antidemon/Clone_Theory_SAD1024.jpg

Please, I think that now it's easier to help me fix my unit, I'll repost some voltages I measured...

One big problem the SAD1024 IS getting hot!!!

From these voltages I cold not understand why it's hot or the problem...

---SAD1024 pins---
1 - gnd 0v
2 - in A 2,5v
3 - 6,7v
4 - n/c 0v
5 - 3,9v
6 - 4,3v
7 - vdd 12,3v
8 - 6,8v

9 - 12,3v
10 - 6,8v
11 - 1,1v
12 - 1,1v
13 - n/c 0v
14 - 6,7v
15 - in B 2,5v
16 - gnd 0v

Pins 3 and 14 are connected, as well as 7/9, 8/10, 11/12
Measured with the SAD1024 in place, then I took the 1024 out and just the pins 5 and 6 changed to 0v.

---CD4047AE pins---
1 - clock pulsing 5,5v
2 - *varying around 6,7,8v
3 - 5v
4 - 13v *connected to pins 5,6
5
6
7 - 0v *connected to pins 8,9,12
8
9
10 - 6v
11 - 6v
12
13 - n/c clock pulsing 5,5v
14 - 12v

Thanks to Steve D., Mark Hammer and all!
Please I want to fix it, but I have no experience with BBDs...
Kleber AG[/url]

[puretube]

pins 10/11 of the 4047 should be pulsating in opposite phase @ half the freq. of pin 1.

[puretube]

turn "gain" trimpot at section1 of the SAD away from ground!

[Kleber AG]

Danke schön!  Puretube

I turned the gain trimpot away from ground but nothing changed, it is still getting so hot...

And pins 10 and 11 of CD4047 have a "stable" voltage around 6V not pulsing at all... :?

*And when I turn the Blend (chorus/vibrato) all the way counter-clock-wise I have no sound at all...

Could it be a fried or bad CD4047 causing all this problems even heating the SAD1024??? Because of the not pulsing 6v at CD4047 10/11 pins?

I must try to find a new CD4047 soon...

Any other sugestions? Please!
Regards
Kleber AG

[puretube]

check, if the 4047 outputs pulsate, when SAD1024 is out of the socket;

if it still does not show clock-pulses, the problem is right in/at the 4047;

if it does show clockpulses when the BBD is out of the circuit, but doesn`t when it is in, then you probably have a SAD-problem;

however, if the SAD is OK, but just doesn`t get clockpulses,
it will not pass on any "sound", and might (??) get hot (especially with that trimpot-wiper at ground.

when it has gotten too hot, it can stop working forever :cry:

[Kleber AG]

check, if the 4047 outputs pulsate, when SAD1024 is out of the socket; if it still does not show clock-pulses, the problem is right in/at the 4047;

Yes even without the SAD it still does not pulse, stable around 6V. I think its good news, isn't it???

however, if the SAD is OK, but just doesn`t get clockpulses,
it will not pass on any "sound", and might (??) get hot (especially with that trimpot-wiper at ground.

Then you're really right, that would explain the SAD getting hot!!!...?

when it has gotten too hot, it can stop working forever

:shock: That would really be sad........... Hope not...

Definately I have to get a new 4047 soon...
Danke Puretube!!!

[Kleber AG]

As almost all of you may know I bought a broken EH Clone Theory, and I've been trying to fix it, help me please!

Today a new 1024 and 4047 arrived from Small B. and I tried with only the "NEW CD4047" in the circuit to check pins 10 & 11 for the pulsating "DC?" voltage.
Pins 10 & 11 are not pulsating they are near 7Vdc :oops:  :cry:  :cry:

Of course I've not tried the "NEW" SAD1024 yet, because I dont want to "cook" it  :?

I searched around the CD4047, "what could be wrong" and I thought the 2818_Jfet (Note that the schem calls for 2N4302) could be bad, then I tried an "equivalent?" MPF102??? But NOTHING changed (I've checked to acomodate the Fet pinout differences)

HELP!!! HELP!!! HELPPP!!! help... help... help :cry:
Regards
Kleber AG

[Dan N]

Have you checked that the lfo is sending the pulses to the fet and the 4047?

[mikeb]

Do you have a changing voltage at the wiper of the depth control (should increase in amplitude as you turn the depth control up)?

Mike

[puretube]

check, if the outputpins of the 4047 show clockpulses,
when you take out the FET.
(it should run at its minimum clockrate, now).

If it does show pulses @ pin 10/11 now,
the pinout of the FET was wrong....

(I don`t have experience with the 4047 [I use the 4046 in similar cases],
but actually, when the "clock-side" is working properly,
the "output" should show the corresponding clock, too).

Don`t put the SAD into the socket, before the clock is working!!
And once it`s working, put in the old chip first...

[Kleber AG]

""WE"" WILL fix it!!! :evil:

Do you have a changing voltage at the wiper of the depth control (should increase in amplitude as you turn the depth control up)?

Yes, exactly as you described. At max it's 4.7Vdc

Have you checked that the lfo is sending the pulses to the fet and the 4047?

Well I "guess" the LFO is the 4558 around "rate" and "depht" pots, if so the answer is yes, as I have the depht wiper sending pulses...

If I change the "rate" pot, this pulsing at the depht wiper also changes the velocity (rate) it pulses...

check, if the outputpins of the 4047 show clockpulses,
when you take out the FET.
(it should run at its minimum clockrate, now).
If it does show pulses @ pin 10/11 now,
the pinout of the FET was wrong....

Nope there's no pulses at 10&11 pins even without the JFET...
BTW: Does these pulses should have great amplitude?

I measured the LFO 4558 pins too:
1) Pulsing from 4 to 9 V
2) Pulsing from 7,1 to 7,2 V
3) Pulsing from 7,1 to 7,2 V (same as pin 2)
4) GND
5) Pulsing from 4 to 10 V
6) Pulsing from 7,1 to 7,2 V (same as pin 2)
7) *Pulsing* I could not read the DMM as fast, but its pulsing
8- 14.3Vdc

I measured the JFET pins too:
Gate = Pulsing from 1,3 to 2 V
Drain = Pulsing from 6,5 to 6,8 V
Source = Pulsing from 7 to 10 V

Should I try changing the LFO 4558 for a new one???

Please, all the suggestions are welcome!!!!!
Thanks everyone!!!
Kleber AG

[puretube]

err.... - wait -

were you talking bout slow (throbbing) pulses at the pins 1, 2, or 3?
That would be the LFO-frequency;
that is not of interest at the moment;

the clockpulses I mean, are somewhere between 20kHz & 100kHz,
and should have almost power-supply amplitude... (at pins 10/11)
you can`t measure that with a multi-meter
(I thought you were looking at it with a scope... :?: )

[with a DC multimeter, it will look like ~half the supply voltage]

:?

the LFO seems to work OK...

[Kleber AG]

ughhh... :oops:
Sorry... as I said I never messed with time-based effects...
I don't have a scope

Now... I don't know what to check next?
Can you guide me with a DMM? :oops:  PLEASE!

One thing I noted, I only have the dry guitar sound when I turn the BLEND(chorus/vibrato) pot all the way up. If I lower it the guitar sound disappears...

I'm with the circuit in front of me now, at my workbench...

Thanks
Kleber AG

[Kleber AG]

ooops...
I guess it's important to remember that the SAD1024 was getting "hot".
What else could cause that???
Should I try the new SAD? Not that I want to take the risk, but thought about ask... :shock:

Thanks
Kleber AG

[Kleber AG]

Thanks everyone!!!
It's fixed! Working!
Well... in the end it was just subbing the SAD1024. I decided to try the new one and CHORUS!

Now how should be adjusted the 3 trimpots? I've messed with 'em a lot... :?

And the last question:::
It's 220Vac and now I need to convert it to 110Vac, I guess i just have to change the transformer...
Or... I have a power supply with a 18vDC out, could I run it to the 78L15 transistor already at the THEORY board?

We're finishing guys  just a little more and it's a big addition to my rig!!!
Thanks
Kleber AG

[Kleber AG]

1) Now how should be adjusted the 3 trimpots? I've messed with 'em a lot... (I don't have a scope)

2) It's 220Vac and now I need to convert it to 110Vac, I guess i just have to change the transformer? I have a power supply with a 18vDC out, could I run into the 78L15 transistor already in the Clone THEORY board?



Regards
Kleber AG

[StephenGiles]

See your PM
Stephen

[Kleber AG]

:shock:
This forum is GREAT!!! Thanks Stephen!  

The bad news is I dont have a scope...
Is there any scope software I could use in place of a real$ scope???
If someone could point me to a url...

Thanks a lot!!!!!
Kleber AG