miss piggy - transistor problems

[vdm]

hey guys,

after reading along with the piggybacking trannies thread i was inspired to try and build a miss piggy. so yesterday i went out got all the comps and got home and soldered it all onto some perf.

i turn it on and all i get is very quiet hum.. no sound. then i remebered the trim pots and set them both to about mid way hoping that i had just made a stupid mistake and they werent's getting voltage, but alas no sound.

i got out my audio probe and started poking - the beginning of the circuit was giving signal - but as soon as i got to the first transistor - the sound stopped. i changed the battery to make sure that wasnt the problem, but still nothing. i twiddled with the trim pot some more but no cigar.

i don't have a multimeter and was wondering is there an easy way to see if a transistor (or any component) is getting power?

other than that - does anyone have any suggestions as to what the next plan of attack is?

thanks guys,
trent

[javacody]

If you have any LED's, you can check for voltage by seeing if it lights up.

[RobB]

You really, really, really should buy a multimeter.  

The circuit you want to build looks simple but the concept of piggy backing two si transistors is still very new and experimental.  

I couldn't imagine doing electronics without one.  That would be like a carpenter without a tape measure.  

Save up for one.  In terms of functionality (bang for your buck), they're cheaper than they've ever been.  Get one with a transistor gain tester.  You'll find other uses for it such as automotive electronics,  checking power points etc... (once you learn how to use it).

Have a look at jaycar and dse.

[javacody]

I got one for $5 off of ebay. It doesn't test capacitance but it does test resistance, voltage, and hfe among other things. It also tests for continuity.

[mattv]

First couple of steps, check your transistor pinouts and make sure they're getting power.

[smoguzbenjamin]

I got my relatively accurate DMM for about $10. It measures everythng except capacitance, and up to 600v AC and something like 250V DC. They're relatively cheap, but the price jump from cheap-sortof-accurate-good-enough type DMM's to accurate high-quality DMM's is large.

[brett]

Hi.  I might be partly responsible for this - are the transistors in the right way around?

The Miss Piggy layout suggested using PN100 transistors but I showed the transistors facing the wrong way for PN100s (at least the ones that I got from DSE).  If your transistors are collector-base-emitter when facing you (ie flat side), then the flat side should face *left* on the circuit board (ie the input end).

It's definately worth perserevering - the Miss Piggy is a totally awesome fuzz.  The more I play it and the more I compare it with other circuits the more I realise how very good it is.

Also, get along to Dick Smith - they had multimeters for $10 recently.  Alternatively, the one I use is from Jaycar and only costs $16.  When I started to get into experimenting with circuits I bought an oscilloscope off ebay for $60.  At the time I thought it was a bit over the top, but I use it heaps (especially when stuff doesn't work!).