Maestro FZ-1a, or so it says on the box....?

[drummer4gc]

A friend brought by this "FZ-1a" for me to look at and repair, and it looks nothing like any images or schematics I see online. It's only got two transistors, one is marked 2n4141 and the other appears the be unmarked. It has clearly been worked on - you can see the 9v battery snap, and the original 1.5v battery case is missing. I'm just wondering if anyone has any idea what it actually is!

[R.G.]

"... and this axe was once owned by George Washington, the same axe that he chopped down the cherry tree with. It's been maintained, well: it's had three new handles and two new heads."

[drummer4gc]

"... and this axe was once owned by George Washington, the same axe that he chopped down the cherry tree with. It's been maintained, well: it's had three new handles and two new heads."

damn. it's not even the original board, is it?

[R.G.]

Maybe. Can't tell. I don't know the original PCB well enough.

But if it wasn't too expensive, you got a nice eye-catching box.

[drummer4gc]

well, it's not mine. I only have to figure out how to apply the concept of "repair" to this thing   

[brett]

Hi
can you work out the circuit and post a schematic?
We can then advise what some of the voltages should be.
A starting point is that the base of transistors should be about 0.7V higher than the emitter for NPN devices (0.7 less for PNP devices).
cheers

[drummer4gc]

Hi
can you work out the circuit and post a schematic?

A good question, indeed. Here's a go at it:



I've never drawn out a schematic like this, so bear with me, and feel free to question everything I've drawn. Please use my third picture for reference while I try to sort this out:

On the schematic, the ? capacitor that looks to be forming a filter between the transistors is the large brown cylinder in the middle of the board, striped green black purple yellow orange. I've never seen a capacitor like this, so it's just a guess that that's what it is.

I can't read the volume pot, and the second tranny is unmarked. Other than that, I think I've got it right...touch board to trace though, it looks like a kindergartener soldered it.

Thoughts?

[LucifersTrip]

this is my first thought when I see that...Nashville

[Mark Hammer]

Yeah, drawing looks like a Bosstone to me, too.

Some 20 years back, I bought a non-working Shin-Ei Companion fuzz in a New Brunswick pawnshop because it was $20 (maybe even $15).  DPDT stompswitches cost about that much in those days (hell, I couldn't even buy them anywhere where I was living at the time, and there were no online parts places, or ways to order online, in those days), and here I got a stompswitch, jacks, AND a box for the same price.  I stashed the board (since rehoused in a 1590B), and used the box and hardware to make my nephew a 4049-based distortion pedal during his metal-band days.  I think he may have eventually ditched it, or lost it, or given it away, so somewhere out there, somebody has a pedal that looks for all the world like a Shin-Ei fuzz on the outside but is nothing of the sort on the inside.

On the flipside, a buddy gave me a FZ-1S board a couple years ago, and all that was missing was the original box.  The board and pots are stock.  I rehoused it in a 125C and it sounds pretty dang cool.

Books and covers - not always predictive of each other, are they?

[midwayfair]

lol, that's awesome: Someone put a Bosstone in an FZ-1A. No accounting for taste!

[drummer4gc]

Thanks guys, nice pluck!

[Govmnt_Lacky]

Whats with the rubber baby buggy bumper on the face?   

Also, that (what appears to be) resistor in the lower right corner looks like it is begging to be replaced!

Looks like they added the DPDT pot to turn the battery on/off. At least THAT was a decent idea 

Finally, what the heck is that brown glob in the middle of the board? (the one with the green, black, purple, yellow spots) Is that a capacitor??

[Mark Hammer]

Finally, what the heck is that brown glob in the middle of the board? (the one with the green, black, purple, yellow spots) Is that a capacitor??

The color code sugges ta 47pf cap, which I gather is what goes in parallel with the 18k resistor.  Gotta love those older big ceramic caps.  Bumblebee caps?  Tropical fish caps?  Bah!!  Gimme coconut head caps!! http://www.seashellcity.com/homedecor/coconut_heads_1.html

Man, that's one butt-ugly PCB.  Somebody appears not to own a file. 

[Govmnt_Lacky]

OUTPUT jack?? 

[Hemmel]

OUTPUT jack?? 

THAT's why it's not working ! No output !!! 

[drummer4gc]

That single jack actually is the output jack. If you look in the first picture, you can see the grey hardwired instrument cable with a male-male 1/4" adaptor added to it.

I'm terrified to take an iron to this thing, it looks like it might crumble....

[aron]

Poor pedal!

[Paul Marossy]

That single jack actually is the output jack. If you look in the first picture, you can see the grey hardwired instrument cable with a male-male 1/4" adaptor added to it.

What's wrong with it? Did you check out the "input cable"? That cable might be dodgy after all these years...

[drummer4gc]

q1 was no good. replaced it with a 2n2222a and it wails I'm going to put this circuit in another box for the guy though and remake a real fz-a1 on vero for him.

[Paul Marossy]

q1 was no good. replaced it with a 2n2222a and it wails

Nice work. There's not much in this circuit that can go wrong. 

I'm going to put this circuit in another box for the guy though and remake a real fz-a1 on vero for him.

That's the right thing to do.