For a matter of debate...I have been looking at these 'Torres kits' ...Would this be better than buying my caps ect from my local electronics store.

Quote from: n9voc on February 09, 2008, 12:27:01 AM
:tu: Short and sweet speaker test:

1) remove speaker from circuit (desolder one side, unplug from cabinet .. whatever, just so you can "get" to both terminals electrically without having it interface with other portions of the amp)

2) Get a DMM, put it onto ohms scale of 100 ohms or less.

3) Drop leads across speaker terminals, listen for slight "pop" as you connect and disconnect dmm onto terminals - and note what ohms reading it is.

The "pop" tells you that the speaker is functional, the ohms reading gives you an idea of the speaker impedance (approx 4 ohms, 6 ohms, 8 ohms, 16 ohms ... etc).

Physically examine the speaker cone, if necessary, repair any small tears (small drop of glue with tissue seems to work well for me).  (or use the info gained above to replace with a new one).

Ive attached a zip file with the schematic and layout of the 5F and AA764 versions of the Champ.  You can find all of the Schematics and layouts for the many generations of Fender Champ from various websites. :tu:

Cheers that's a real help....

Cheers for the info....

I got this from a junk shop for 30e and didn't know it was a classic amp.

I normally repairs synths so the recap will not be a problem and i will check everything out and give it a good clean up.

I like to get as much info as possible before i get into this, Maybe this is a dumb question but how can i test this speaker..?

Again thanks for all the advice...

Sam.

Quote from: LJ King on February 06, 2008, 09:32:51 AM

New tubes,
New electrolytics (caps),
New speaker.

Does replacing the speaker make a difference to it's original sound...?

Which are the best brand of tubes..?

I have a mid seventies champ...It's not very clean sounding and kind of distorts.

I would like to give it a service..What should i look for..?

Thank you for the good advice..

I will try to locate some of that spray.

I did go over the board for cold joints but I must have missed something.

Sam.

Update...It seems that if i leave it on for half an hour..It works again.

Quote from: LJ King on January 18, 2008, 07:00:05 PM

Quote from: joecool85 on January 18, 2008, 06:07:40 PM
I knew it wasn't anything kinky, but I know google would think it is.  Thanks for the explaination though, I'd never heard of that.

You don't really need to wet the finger either. Try it on your input cable. (duh)

I didn't have the input cable around as i was looking at the circuit board...

Anyway i went over the board for bad joints ect....As it happens it all started working again.

But after a week it's stopped again...So what's going on.

I need some schematics or advice on where to look next...?

Quote from: joecool85 on January 18, 2008, 03:03:16 PM
What is the "wet finger test"?  I don't dare google that one lol.

It's nothing kinky...If you wet your finger and place it on the opamp on the input stage you get a buzz that can indicate the stage is working...However it started working instead..
The BA before the number just indicates the maker of the chip.
To answer my own question.

Hi ..I am new here so i hope this is in the right section.

My gr50 stopped working...I opened him up and noticed a BA4558 on the input circuit..So i did the wet finger test and it all started working again. Switched off/on and it was not working again.

I have replaced the BA4558 with another 4558...But it's not solved the problem.
Is the BA different than the normal 4558's...?

I can't find any schems...So could someone help here who has experience on these...

Cheers....