Pignose Hog 30 bass amp - Guitar amp repair?

Post by **The Robman** » Mon Jun 12, 2017 8:18 am

Anybody here have any experience fixing guitar amps? I have a Pignose Hog 30 bass amp that cut out mid-performance. I've taken it apart and checked the input jacks and they're good. None of the caps looks like they've popped or are swelling and the volume/tone pots all show resistance increase and decrease when the knob is turned. I've read where others have replaced the pots and got their Hogs working again, so I might try that, but if anyone has any others ideas, please share.

http://www.musiciansfriend.com/amplifie ... hog-30-amp

Post by **vickyg2003** » Mon Jun 12, 2017 6:44 pm

I know your wife is a musician. Are you the guitar player or just the financially responsible party?

Semi related: I just streamed an interestong video, "The American Epic Sessions"
from pbs.org about a guy that took 10 years to rebuild one of the early record cutting amp/ lathes. Jack White and T Bone Burnett lead an epic recording sessions using the only working 1920s recording device in existence. The recording device is timed by a weight-driven system of clockwork gears. It was really interesting although the musical style of the recordings sessions might not suit you. Its quite different than the musical group you used to link to. Its only available online till July 7. It rins 2Hrs. You might like it.

Post by **The Robman** » Mon Jun 12, 2017 9:51 pm

Actually both of my kids are musicians too now! Casey (my youngest) is a guitarist and also a bassist, and now Sean (my eldest) has also started playing bass. But this amp is my wife's, I'm just trying to fix it.

I'll look for that video.

Post by **vickyg2003** » Tue Jun 13, 2017 10:16 am

I know you love music, so you must be very proud to be part of such a musical family even if you are just the Roadie!

It looks like there have been lots of versions of this amp. Is there a model number that might help identify the correct schematics?

Post by **The Robman** » Tue Jun 13, 2017 10:17 am

Here are some things that I have found on the web (just to keep the links in one place):

hog 30, broke and fixed:
https://www.squier-talk.com/threads/hog ... xed.56409/

Hog 20 fix ......rewiring circuit board
https://www.youtube.com/watch?v=xaE9mo5plEU

Pignose Hog 20
https://www.ssguitar.com/index.php?topic=1166.0

Apparently the amp is the same one as the one used in the Gorilla GB 30 amp.
https://reverb.com/item/4829581-gorilla ... 2001-black

Pignose shop:
https://pignose.myshopify.com/

Amazon page (for customer reviews):
https://www.amazon.com/dp/B0002D0K00/

Warehouse Speaker:
https://wgsusa.com/8-g8c-20-watts

Post by **The Robman** » Tue Jun 13, 2017 12:14 pm

vickyg2003 wrote:It looks like there have been lots of versions of this amp. Is there a model number that might help identify the correct schematics?

Hmm, not that I'm aware of, it's just the Hog 30, but I'll take another look, and I can post pics of the PCB if you like.

Post by **The Robman** » Thu Jun 15, 2017 3:40 pm

vickyg2003 wrote:It looks like there have been lots of versions of this amp. Is there a model number that might help identify the correct schematics?

Hey Vicky, here's the schematics:
http://www.hifi-remote.com/forums/dload ... e_id=14582

Edit: there is a typo in the schematic, IC2 is really a TDA7240A chip, not a TA7240A.

IC1 is a JRC4558 chip.

Post by **vickyg2003** » Fri Jun 16, 2017 7:01 pm

We all know that I know nothing about electronics, I just wanted to try my hand at googling.

underquark · Post by **underquark** » Thu Jun 22, 2017 5:15 pm

Unfortunately the last time I serviced an amplifier it looked a bit like the one here. All my experience with modern electronics has been with blown power supplies so maybe check the power supply side of the amp? Is it really a 12V DC input and is that from a battery, external power supply or internal transformer/switched mode PSU? It might just be something as simple as a dry solder connection, of course.

Post by **The Robman** » Thu Jun 22, 2017 7:54 pm

It is really 12v, there is an external power supply and there are two 6v batteries (it's a portable amp). This isn't an amp head like yours, this is a small combo amp.

The power supply appears to be working as the LED does light up. I started taking voltage readings but accidentally shorted something and blew the fuse, so I had to order more, which just arrived today. I have ordered replacements for the 2 ICs so plan on trying to replace those to see if that does it.

More info starting at the post here:
https://www.talkbass.com/threads/pignos ... t-20140636

Post by **The Robman** » Sat Jul 08, 2017 5:44 pm

Quick update for anyone following this, I have fixed the amp. The problem was the main "bridge amp" IC chip (TDA7240A). It shows as being discontinued at both Mouser and Digikey so I had to go to ebay to find it. I bought it from this listing from seller polida2008.