Bass Amp Repairs

[KickAxeUSA]

Hi all. I am new to this forum and am glad I found it! I have been setting up, building and customizing electric guitars for some time now and have also biased a few tube amps. I just felt that repairing amps would be the next logical step. What I need is some general coaching and info on amp repairs and have 2 bass amps that I have as "practice" repair amps. They were both given to me by people that felt that these amps were throw aways and they bought new amps. I hope to fix them and learn while fixing them. One is a Crate BT50 and the other is a Fender M-80. What I did find was a couple of burnt resistors and capacitors (that look like resistors). These seem to be on the output board. I am not actually sure what ckt board it is called. But, this is where a good schematic and diagram (block or otherwise) of the amps would help. Any and all help is greatly appreciated!

[Fragger]

A good place to start on this board is a Search.

[KickAxeUSA]

I did search and couldn't find schematics......but it seems that Enzo is the one to ask about schematics..............how 'bout it Enzo.....could I please get some schematics with voltage test points on this? Thanks for your help in advance!!!

[KickAxeUSA]

Found the schematic for the M80 on Fenders website after some searching and rooting around in there. Re-soldered all components and the problem is fixed! Noticed a few posts on the lower end Fender amps needing this done. Didn't do the upgrades though. Still looking for the schematics on a Crate BT50 bass amp....any help would be greatly appreciated.

[KickAxeUSA]

Fragger...........any other suggestions? Seems that no one here can get those schematics including me

[Enzo]

If you call Loud technologies, the folks who make the Crate amps, they would have sent you the drawings.

[KickAxeUSA]

Enzo....thnks alot for your help! It is greatly appreciated!!! I did try calling Loud Technologies Inc. (800-898-3211) tech line and after 2 times on hold for over 45 min. and 1 time getting diconnected (like someone lifted the reciever and then hung up) I thought I would have a better chance via this forum. And you proved that this forum is BETTER. I will and do try to get information through the proper channels when possible. I know that most of you folks here are of the working class as I am and I won't take your time for granted. Again..........thanks to you I will be able to repair this amp. The 2 components burned were R25 and R30. Both are 4.7 ohm resistors.

BTW - Do you know where I might be able to purchase amp schematics on disc. I know that is a broad question (regarding makes and models) but I need to start getting a collection going soon. Maybe even some training videos / books. My day job may dry up here real soon and I will need to be going full time in the guitar / amp business. Hopefully it will sustain life as I know it. Darn economy seems to be hurting alot of people everywhere.....Thanks again and God Bless!

[Enzo]

When you call them or any company, determine when they open in the morning and call then. First thing. Ask the receptionist when customer service opens. Later in the day, the phone backlog grows.

In the case of Loud, I know I cannot order parts after 3PM their time. And I am one of their service centers. I am not sure if there is a morning tome as well, like not before 10AM or something.

SLM used to make a schematic disc, but now the drawings are all online at Loud. Fender makes discs. GK does or did. Yamaha and QSC make discs. Off the top of my head, I can;t think of who else sends out discs. I don;t know if ANY of those are available to the public, they are intended for service centers.

Aspen Pitmans Tube AMp Book, the fancy version comes with a disc full of old schematics. Not sure if there are many that are not also on SChematic Heaven, but it is a handy collection in one spot.

Start your own disc. Download whatever you want and save it. Certainly no shortage of schematic on this forum. The SLM and Fender and GK discs I have I have dubbed onto a flash drive anyway. Not only is it faster to access, but I don;t have to fumble around changing discs in the reader. SO download drawings and park them in a $10 thumb drive.

ANything that comes on a disc is probably easily obtained from the factory anyway.

[KickAxeUSA]

Never thought of using a thumb drive.....I use one for all my backup files though. Does make sense since seek time is faster and you can have alot more on it. Thanks again for your expertise!