SAD1024 MN3007 or MN3207 retrofit board?

[jaysg]

I found and studied this thread, but I don't see a couple of things -- a vero layout, or a pcb for sale.   If these exist, can someone help me here?

http://www.diystompboxes.com/smfforum/index.php?topic=78270.0

I have a dead 18V electric mistress on the way.   From what I've gleaned, it's probably a dead bucket brigade chip.

[Dave W]

If you need a PCB, I'm sure you can get somebody here to make you one.
That's what I did. 
Try giving John Lyons a PM. He does nice work.

[jaysg]

hmm...100 views.   I guess it's time to re-invent the wheel.   

[Scruffie]

hmm...100 views.   I guess it's time to re-invent the wheel.   

When i'm not quite so hungover i'll try and get to a Vero layout.

[jaysg]

When i'm not quite so hungover i'll try and get to a Vero layout.

ooo ooo...sounds good.  Drink water!

[Scruffie]

When i'm not quite so hungover i'll try and get to a Vero layout.

ooo ooo...sounds good.  Drink water!

Okay, i've had some water and sleep since then 

Do you have any space constrains you'd like me to stick to? May aswell get this right the first time.

[jaysg]

Okay, i've had some water and sleep since then  

Do you have any space constrains you'd like me to stick to? May aswell get this right the first time.

I don't know how to insert pictures.  That long thread I mentioned contained a PCB layout and pics of it implemented.  It's probably  1/4"  taller than the 4049 chip and 1.5 times that wide.  If that's roughly 1" x 1.5", a vero layout might take 50% more space?

btw, one of the vendors I asked about this, said that if there was a clean pcb implementation, he'd like to sell it.

[oldschoolanalog]

...btw, one of the vendors I asked about this, said that if there was a clean pcb implementation, he'd like to sell it.

Translation: Let somebody else do all the work then STEAL their efforts and capitalize on it.
This personifies why people "show & don't tell".
Nice.

NOT!!!

I'm done here.

[Thomeeque]

 Dave, I think that if jaysg would like to steal and capitalize our effort, he would quietly do it without telling us

IMO he just says "Hey guys, it's not only me interested, there may be market for your PCB", which is interesting information.

T.

[oldschoolanalog]

Whatever.
I just hope you (Tomas) get your due. Considering the fact that you did all the design work.
Besides, the retrofit is about alot more than some daughterboard. Still gotta' get it installed and make the necessary changes to the circuit to get it working.
I wonder who this anonymous "vendor" is.
Have fun y'all!
Later...

[jaysg]

Dave, I think that if jaysg would like to steal and capitalize our effort, he would quietly do it without telling us

IMO he just says "Hey guys, it's not only me interested, there may be market for your PCB", which is interesting information.

T.

Yes...I infered that there was a market for it...no one's getting much more than fun out of it, but there are bucket brigade products out there that in need of help.  I'm still waiting for the EM to arrive and it may not be the SAD1024, but there's a reasonable chance it is.

My deal is that I'm capable of pulling the datasheets and figuring it out for myself, but one of my profs hammered away hard on the intelligence of not re-inventhing the wheel when you don't need to.

[jaysg]

Okay, I have it now.  There was a bad 4558 and Vcc read 1.6V.  After replacing it, it doesn't flange.   I have it on a 16V power supply.  With the 4558 out, Vcc reads 12.65V.  With the 4558 in, it slowly varies from 8.3 to 9.6.   Is that normal?

The LFO circuit puts out nice square waves on pins 12 & 13 of the 4013, fwiw.  They vary with the Rate and Range controls.  I don't see what the switch does yet. (All on a scope with a fixed sine wave input).

Anyone know of a debugging page/significant resource on the net?   I slogged through the archives here, but it's thin pickings.

[Scruffie]

Okay, I have it now.  There was a bad 4558 and Vcc read 1.6V.  After replacing it, it doesn't flange.   I have it on a 16V power supply.  With the 4558 out, Vcc reads 12.65V.  With the 4558 in, it slowly varies from 8.3 to 9.6.   Is that normal?

The LFO circuit puts out nice square waves on pins 12 & 13 of the 4013, fwiw.  They vary with the Rate and Range controls.  I don't see what the switch does yet. (All on a scope with a fixed sine wave input).

Anyone know of a debugging page/significant resource on the net?   I slogged through the archives here, but it's thin pickings.

Dunno but CMOS chips die more often than not, change out that 4013.

Still gunna get on that 1024 to 3007 vero but other stuff has come up for a little while... there's alot more that could go bad before assuming it's that.

[Thomeeque]

Okay, I have it now.  There was a bad 4558 and Vcc read 1.6V.  After replacing it, it doesn't flange.   I have it on a 16V power supply.  With the 4558 out, Vcc reads 12.65V.  With the 4558 in, it slowly varies from 8.3 to 9.6.   Is that normal?

No, V_CC cannot vary this way, it should be stable - either you have very weak power supply (check it's voltage when it's in use) or circuit loads too big current due to some failure (measure total current) or there's something wrong with stabiliser (or you are not measuring it correctly).

First, can you confirm that we are talking about this EM:

http://img210.imageshack.us/img210/9172/18vmistressschmhr5.gif
http://img357.imageshack.us/img357/5590/ehelectricmistressukhq5.jpg

? T.

[jaysg]

No, V_CC cannot vary this way, it should be stable - either you have very weak power supply (check it's voltage when it's in use) or circuit loads too big current due to some failure (measure total current) or there's something wrong with stabiliser (or you are not measuring it correctly).

First, can you confirm that we are talking about this EM:

http://img210.imageshack.us/img210/9172/18vmistressschmhr5.gif
http://img357.imageshack.us/img357/5590/ehelectricmistressukhq5.jpg

The first schematic contains major differences around the supply regulator.  The second is closer to the EM I have.  The board I'm looking at is 5200-1A.  I've found several pics on the net of 5200-1C....close, but who knows what minor changes there are.  Anyway, I'm not going to clip out the LM339 until I have a chip to replace it.  I've replaced the uA741 and the 4558, which was dead.  I don't have a extra 4013 yet, so I haven't swapped it.  Experience tells me that it's likely to be semiconductor that's root cause....and maybe I should shotgun the electrolytics.

After powering up, it draws about 9mA, which seems low considering all the active parts.

Thanks for keeping up with this guys!

[Thomeeque]

http://img210.imageshack.us/img210/9172/18vmistressschmhr5.gif
http://img357.imageshack.us/img357/5590/ehelectricmistressukhq5.jpg

The first schematic contains major errors around the supply regulator.

If you read green values, only difference around the supply regulator is missing 10u tantal over 6V8 zener (first pic probably covers more revisions).

 After powering up, it draws about 9mA, which seems low considering all the active parts.

Well, if you have 16V at input and V_CC varies from 8.3 to 9.6 at this small current, there is definitely something wrong with the regulator, I'd check it's transistor (you can probably try any other general purpose PNP, if you don't have 2N4354).

On the other hand you probably don't have to change 4013, whole LFO and clock seems to work properly from what you have written before..

T.

[jaysg]

If you read green values, only difference around the supply regulator is missing 10u tantal over 6V8 zener (first pic probably covers more revisions).

Well, if you have 16V at input and V_CC varies from 8.3 to 9.6 at this small current, there is definitely something wrong with the regulator, I'd check it's transistor (you can probably try any other general purpose PNP, if you don't have 2N4354).

hmm...I have some 2N4125s...no other PNP's lying around.  I'll give it a try.

[edit]woohoo...12.86V_dc and stable.  Lunchtime...

[Thomeeque]

If you read green values, only difference around the supply regulator is missing 10u tantal over 6V8 zener (first pic probably covers more revisions).

Well, if you have 16V at input and V_CC varies from 8.3 to 9.6 at this small current, there is definitely something wrong with the regulator, I'd check it's transistor (you can probably try any other general purpose PNP, if you don't have 2N4354).

hmm...I have some 2N4125s...no other PNP's lying around.  I'll give it a try.

It should be OK, just be careful about pinout, which may differ.

Btw. you could pull-out this 2N4354 and feed whole circuit thru 7812 regulator, if you have one.

T.

[jaysg]

It works now.  Thank you so much for the help!   Am I a putz if I add an LED to this thing?  (It came missing the footswitch, the output jack, and foam battery holder.)

Also, I keep finding people talking about a unity gain mod, but I can't find the circuit.

[Thomeeque]

It works now.  Thank you so much for the help!   Am I a putz if I add an LED to this thing?  (It came missing the footswitch, the output jack, and foam battery holder.)

Also, I keep finding people talking about a unity gain mod, but I can't find the circuit.

My advice would be:

If you plan to keep it, add LED, unity gain mod and e.g. BBD output signal invertor (to make some use of 2nd half of unity gain opamp) for more instant fun (adds this sound) Other interesting options are clock range switch, feedback capacitor switch..

If you plan to sell it, just fix it and sell it as it is, people want the original most (AFAIK).

Make your choice first

T.