May 8th, 2012, 04:51 PM
I've got a73 Pro Reverb and I've got to change the electrolytic capacitors since they are the same ones that have been their since 1973. Could anyone give me any information on which ones to change or where I can find any information on the subject.Thank you.
May 8th, 2012, 07:58 PM
May 9th, 2012, 12:42 PM
WARNING: dangerous voltages present...even when the amp is unplugged.
May 9th, 2012, 01:07 PM
I'll second Wally's very important point.
For what it might be worth, there are a couple of tools that I personally find helpful when working on an amp:
1. A Weber Snuffer Stick (here: https://amptechtools.powweb.com/stick.htm) to discharge the filter caps, and
2. A good multimeter (a Fluke, for example--here's mine: http://www.fluke.com/fluke/usen/digital-multimeters/fluke-117.htm?PID=55996), always used when using my Weber Snuffer Stick to make sure I've taken the caps down as far as I can with the Stick.
Be careful, live long and prosper!
May 9th, 2012, 01:38 PM
I could be wrong here....but when I read a question like catar has posed, I am highly suspicious that it is professional tech time. Ime, anyone who asks this question does not have the experience to get off into trying to repair an amp like a PRo REverb. Ime, there is a lot of reading and studying and perhaps working on simpler circuits to do before a beginner should take on tackling such a job on such an amp. YMMV.......and again...I could be wrong.
May 9th, 2012, 06:31 PM
Thanks everyone for all the great information.
May 9th, 2012, 06:41 PM
2 x 70 or 80mfd/350-450V and 3 x 20mfd/500V filter caps, 7 x 25mfd/25V cathode bypass caps, and 1 or 2 100mfd/100v bias caps depending on what you do to the bias circuit. That is the simple answer.....I didn't mean to offend....just sharing concerns.
Good luck with it.
Danger! Danger! I have to remind myself everytime I get into one of these things.....Danger! for what it is worth, you can drain the caps by hitting a big chord and switching the power switch off while leaving the standby in play position. You will hear the voltage draining away..until there is no signal. Unplug the amp.....and tear into it iif you feel prepared.
May 9th, 2012, 09:41 PM
Does this amp play well now and you just want to change them as a precaution?
Or does the amp have problems and you think recapping it will cure it?
It would be cheaper and far safer to either find a good tech, or if that isn't possible, ship the amp to one of the tech here on this forum.
What you are purposing can be dangerous, and if not done properly can cause more damage.
I'm not a tech, but there are several here that I'm sure could do the job at a fair price. Then your pro reverb may be good for another 40 years.
"Dying ain't much of a living" Josie Wales circa 1865
May 12th, 2012, 04:30 PM
Thanks again for all the great info.