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Topics - AllThorUp

#1
Hi I have this Pignose 30/60 amp and I was looking at the schematic and also the circuit board and was wondering if anyone could tell me what the purpose of LED1 and LED2 are in this circuit? On my amp's PCB they are labeled but not populated.. I'm just curious about them is all. Thanks
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#2
Hi, folks. I was working on this old amp, and looking at the schematic I was wondering if someone could please explain to me what the 2 diodes marked "LED 1" and "LED 2" are doing in this circuit? Is it a clipping section? Because on my amp they were totally missing...  :o I was wondering what that might be doing to the tone of my amp and what might be expected if I were to stick some new LED's (or maybe some other kind of diode?) In those spaces?  ??? If someone could please take a moment to learn me a little something about something I sure would appreciate it. Thanks!!
#3
The Newcomer's Forum / MPSU07 & MPSU57 alternatives?
September 03, 2016, 08:49:01 AM
Anybody able to point me towards some alternative replacement driver transistors for this pair? (MPSU07 & MPSU57) Those 2 are a little pricey, and apparently arent made anymore, so i was hoping to find an alternative that was a bit more cost effective. Thank you, I appreciate it very much.
#4
The Newcomer's Forum / Pignose 30/60 repair. help!
August 30, 2016, 01:54:18 PM
Hi so I found this forum while google searching about this amp I am trying to fix.  ive been following an old thread as my instructional guide to fix my 30/60.  Ive gotten as far as replacing the transistors and turning it on using the light bulb limiter, which is where the old thread ends because for the OP his started working at this point. Well, as far as mine goes, lets say im not so lucky. So, it no longer immediately blows the breaker when i switch it on but the bulb limiter still glows brightly and im getting what i believe is DC hum from the speaker.  any advice on where to go from here would really be greatly appreciated!!

On a side note it appears someone mucked around with this amp sometime before i got ahold of it, because the 2 most notable things were that LED 1 and 2 which i assume to be a clipping section, have been replaced with a pair of diodes, and the other is that the 2955 transistor was replaced with a different one (whos numbers i cant recall at the moment, and took a bit of searching to find what it was) but the 3055 was there still. Dunno if those alterations could have contributed to it landing in its current state of non op, but figured it was worth the mention.