Maestro FZ-1A

[goatsounds]

I think I need a little help with my Maestro Fuzz FZ-1A clone.

This is the schematic I used: http://fuzzcentral.ssguitar.com/schematics/fz1a.gif

Everything on my PCB is great, and perfectly after the book, all components are great, my hard-to-find very-expensive transistors (2N2613) work, and my 1,5V PSU (1,7V like a new fully charged battery) work great and stabile without hum and noise (I've tried with a 1,5 bat. too).

But inspite of all that, my transistors won't switch "on".  When I set up everything I just get a loud humming noise from the amp.

Does any of you have experience with that kind of guitar pedals?

FYI. The transistors are PNP Germanium

With com on the emitter on the first trans, from base to emitter, I get -1.5mV. In my head I should get around -600mV..
From collector to emitter I get full supply voltage...

I'll post a pic of the schematics with my measurements. Red point is + on my voltmeter, and black points are the com-port.With com on the emitter on the first trans, from base to emitter, I get -1.5mV. In my head I should get around -600mV..
From collector to emitter I get full supply voltage...

I'll post a pic of the schematics with my measurements. Red point is + on my voltmeter, and black points are the com-port.

[smallbearelec]

You say that "everything on my PCB is great" but you don't say whether you made the board or purchased it. If it's a home-made board, maybe there's a problem with a trace. Also, are you sure that all of the transistors are inserted correctly? C, B, and E in their right places?

I did an NPN clone of this thing:

http://diy.smallbearelec.com/Projects/FuzzE-One/FuzzE-One.htm

and my notes on how I lined it up might help you.

[duck_arse]

when you do your measure, put the black lead on the ground connection, then put the red probe on c - b - e. that way all the voltages are referred to ground. can you repost your voltages using this method, please? we'd next ask for pictures of your build, and I should have sent you to read "what to do when it doesn't work", on the "building your own stompbox" index page, but haven't.

and welcome to the forum.

[Quackzed]

isn't the ring connection on the input connecting to ground when a cable is inserted? i'm not good with positive ground wiring tho, but it looks like the + battery lead is connected to ground when a cable is in... maybee its just a naming convention and all the grounds are actually positive... but then wouldn't whatever previos pedal's sleeve ground be connected to the + battery when cable connected... and thus ground the battery?!?
sorry, just something to check... like i said , i don't know positive ground basics, just seems weird to me...

[goatsounds]

smallbearelec:
I made a very fine little PCB at first. No shorts ore anything. When I found out it didn't work, and after hours of trouble shooting I decided to try and make a new PCB (not that great looking, but all right) but with the new PCB I get the same results.
Your build looks very tempting. Do you have any audio-examples?

duck_arse:
Thanks
First trans: E: -27mV B: -28mV C: -1.79V
Sec. trans: E: 0.0mV B: -7mV C: -1.76V
3'rd trans: E: 0.0mV B: 0.0mV C: -1.76V
Pics will follow in a sec.

[goatsounds]

You get links to the big files:
http://imgur.com/XCZtenL
http://imgur.com/T58ccKX

This is the ugly test PCB.
The first was very fine, with beautiful wirering and all. 

[antonis]

You get links to the big files:
http://imgur.com/XCZtenL

It seems to me that you've wired the Input (green cable from tip) straight to the centre lug of Volume pot...!!!
(an the upper lug of the same pot to PCB In...)

[goatsounds]

You get links to the big files:
http://imgur.com/XCZtenL

It seems to me that you've wired the Input (green cable from tip) straight to the centre lug of Volume pot...!!!
(an the upper lug of the same pot to PCB In...)

Hmm. I've wired the input (black plug to the left) to the switch and then to the input on the PCB. Output from the PCB goes to the left lug of the volume pot. Center lug goes in the switch, and then to the output plug (open plug to the right)

[antonis]

Hmm. I've wired the input (black plug to the left) to the switch and then to the input on the PCB. Output from the PCB goes to the left lug of the volume pot. Center lug goes in the switch, and then to the output plug (open plug to the right)

Stereo jack confused me... - thought it served as Input jack

[smallbearelec]

Given those voltage readings, I suspect some error in the PCB pattern. Make a clean copy of the schem. Set your multimeter to continuity. Probe between the Base of Q1 and the hot side of the 1 Meg resistor. If you get the BEEP, mark off on the schem with a highlighter and test another connection; if not, figure out WHY there's no continuity. Do this for every joint and trace on the board, and you will find something that's not right. Also make sure that you have correctly identified and connected Tip, Ring and Sleeve of the input jack and Tip and Sleeve of the output jack.

I'm sorry that I didn't know you when you started this project; making your own PCB has numerous land mines, and the learning curve is steep. I usually suggest breadboarding and then learning to wire on perf before attempting to design a PCB layout.

A number of people have built my version successfully, and it sounds suitably splatty. The schem you have will work if all is wired correctly and the devices are good.

[Riinehart]

Hi all,

Apologies in advance for my inexperience. As this seems to be the most current FZ-1A thread, I thought it might be a good place to ask for help.

I have an old, original FZ-1A that was given to me quite a while back. I haven't used it in a long time, and taking out recently I see that it's ceased to function. When bypassed with the footswitch, signal passes through fine. But when turned on with the footswitch, I get nothing at all.

I have some decent experience with soldering, and have a multimeter, but sadly no real experience troubleshooting a circuit.

Would any of you have any suggestions where to start? New battery, and reading correct voltage at the ends of the battery leads, but that's about as far as I can get.

What are the most likely suspects? Are there any documents anywhere that might note what measurements I should expect at different parts of the circuit?

Sorry again for being clueless. Any help would be greatly appreciated.

Thanks!!

[pupil]

I'm surprised nobody has responded to this yet. I was hoping someone would so I could learn from a more experienced member what the first few steps might be...

Anyway though, the FZ-1A is a simple enough circuit and I think we should be able to get to the bottom of this.

First, I would check that all of the components on the board look connected and that there are no broken solder joints. Especially check that the wires at the jacks and stompswitch look OK. Whew, looking at the guts of some of these old fz-1a right now... those are uggggleeey on the inside. It might take you more than a minute to visually inspect everything.

If it looks that everything is mechanically connected then I suppose that checking the voltages at the legs of each transistor is a good place to go next. Give us these voltage values with the pedal turned on:

Q1Collector
Q1Base
Q1Emitter

Q2C
Q2B
Q3E

Q3C
Q3B
Q3E

hints:

-before you take the readings you will need to (A) locate which transistor is Q1, Q2, and Q3, (for this you will need a schematic) and (B) locate which leg is which according to a datasheet of that specific transistor. It may be hard to find a datasheet and if worst comes to worst just give the values at semi random (use the same order even though you don't know which is collect, base or emmiter) and we should be able to figure something out from that.

-put the black lead on the metal of the enclosure, and the red lead at the specific transistor leg to get the value.

-no value should read more than 1.7 volts

[Riinehart]

Thanks so much for the response. I've been poking around this thing all morning, googling what I can, and haven't had any luck. I've been hoping to learn more about this for a while, and as you said, this seems like a simple enough circuit, so I'm glad to get a chance.

I've visually checked all the connections and haven't found anything amiss yet, as far as I can see.

Regarding the transistors, a disclaimer: I'm very new to reading schematics. I've found what looks like the most reliable schematic online, and hopefully have identified which transistor is Q1, Q2, etc., as well as the relevant legs. But it's definitely possible that I've made a mistake. In any case, here goes ...

Q1C - 0
Q1B - .66
Q1E - .74

Q2C - .28
Q2B - 1.12
Q2E - 1.17

Q3C - .08
Q3B - 1.16
Q3E - 1.17

Thanks so much again -- grateful to have some help!

PS - I have some rechargable AA batteries, and I had a thought that I'd use one of those instead of wasting a battery through all this testing. But I noticed it gets extremely hot, so I've taken it out and gone back to the regular battery. Do you think this has anything to do with the problem, or are rechargable batteries just a no-no for these kinds of pedals?

[Riinehart]

Here's (hopefully, if this works) an image in case it helps.

[Quackzed]

batteries getting hot indicates some kind of short from -1.5 to ground... also you've got -1.17 at q2e and q3e but only -.74 at q1e... thaat spot should be connected directly to - side of the battery, so theres a short somewhere beween q1e and ground...

[Riinehart]

Thanks, Quackzed -- that makes sense. I'll see if I can find anything in that area now. (Also hoping that I didn't incorrectly identify the transistor legs.)

[pupil]

Call me slow, but i'm not sure that what quackzed makes sense to me.

You should be getting 0 volts at Q2E and Q3E b/c they are directly connected to ground. Also you should be getting battery voltage (1.5-1.7v) at Q1C.

Did you accidentally put the battery in backwards?

I'm referencing the Maestro FZ-1A schematic by Jack Orman copyrighted 1995

[Riinehart]

Hmm ... well, the battery is inserted as you can probably see in the photo. Positive to the positive mark on the battery holder and red wire.

Is there any potential harm in trying to reverse the battery to see if that works?

(By the way, I cannot find anything that would cause a short between Q1E and ground, and I get no continuity between ground and Q1E on meter.)

[pupil]

There could be harm, don't do that. Hmmm

[Riinehart]

Could Q1 be bad?

A couple other pictures, closer up, in that area, in case it sparks any thoughts ...