I have a newer pignose 7-100 and it just up and quit. Neither batteries or ac adapter will power it up. Any known issues I should be looking at? Thanks in advance for any and all help
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No such a thing as "common issues" which if really existed would have been solved at the Factory long ago.
You'll have to troubleshoot it.
You'll need fresh batteries (or a power supply) and a multimeter to begin with.
About the only way I'd call anything common issues would be because these are such simple amps, there are only so many parts in it, so there are only relatively few ways for it to fail.
Does it have a power LED that won't light up, or does it not have one anyway?
When you turn it on, is there a little pop out the speaker? If you max the volume, is there any background sound out the speaker?
We need to determine if it is not powering at all, or if it gets power but can't make sound.
There is a cutout contact in the input jack to prevent the amp remaining powered up when nothing is plugged into the input. If that contact fails, your amp will not come on. Check the power switch, it may have failed. Check to see if the 9v power is getting to any of the transistors.
There is no power at all that I can surmise. No audible pop or hum. The bottom of the pcp looks like it has a lot of residual glue from the casing on it creating a haze which I will clean with alcohol and many of the solder joints dont look great so possibly will reflow those. Thank you for the suggestion of the input cutout contact. I hadnt thought of that. What is the best way to check that?
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Ohm meter.
Thanks so much enzo. Your knowledge is so appreciated on this forum.
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Input switch is good, volume pot is good, continuity across the board is good. I am at a loss. Transformer perhaps?
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can you post or link us to the schematic you are using, and does it match your amp?
So the simple stuff seems OK. Now we troubleshoot, no guessing transformers or whatnot. Plug something into the input to complete the battery circuit. Clip your meter ground to the plug sleeve, or use the preamp out jack ground, they should be the same. Now probe for voltage. With switch off we expect zero volts everywhere.
Turn the power switch on, and the volume half up. Now do you measure 9v at either end of the battery itself? Do you find 9v at the collector of both output transistors? How about the collector of the driver? And do you have a partial voltage at the collector of the input transistor?
If any of those are missing, find out why. If they are all present, input a signal and follow it through the amp. Is signal on the wiper of the volume control? is it at the base of the first transistor? Is signal at the collector of the driver? is it at the bases or collectors of the outputs?
This is the schematic I have been using as a reference
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As well as these
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Thanks, now do the procedures I described.
Ouch !!! the second schematic is 'orrible, where did you get it from?
Plus it's incompatible (silicon NPN) with the first one (germanium PNP),don't understand how both can be used to troubleshoot the same amp.
Please post a couple guts and PCB pictures of the actual Pignose you have.
Quote from: J M Fahey on November 09, 2015, 12:58:38 AM
Ouch !!! the second schematic is 'orrible
A work of art almost in its wonderful obscurity. :lmao: