It is currently Mon Mar 16, 2020 9:07 pm

All times are UTC - 7 hours



Post new topic Reply to topic  [ 5 posts ] 
Author Message
Post subject: Champ amp parts location help AA764 cap kit
Posted: Mon Mar 26, 2012 10:59 am
Offline
Hobbyist
Hobbyist

Joined: Mon Mar 26, 2012 10:31 am
Posts: 2
Need some to give me an idea where to get a cpacitor kit for this amp, in circuit shows a esak condition on all caps. Parts list that will that will be up to date would be great Thanks


Top
Profile
Fender Play Winter Sale 2020
Post subject: Re: Champ amp parts location help AA764 cap kit
Posted: Mon Mar 26, 2012 2:53 pm
Offline
Rock Icon
Rock Icon
User avatar

Joined: Wed Mar 31, 2010 12:48 am
Posts: 26417
Location: Tombstone Territory
I've seen 450V 20-20-20-20 cap cans for Champs and Princetons on Ebay, priced from around $40 to $80. You shouldn't have any problems finding one.

Arjay

_________________
"Here's why reliability is job one: A great sounding amp that breaks down goes from being a favorite piece of gear to a useless piece of crap in less time than it takes to read this sentence." -- BRUCE ZINKY


Top
Profile
Post subject: Re: Champ amp parts location help AA764 cap kit
Posted: Tue Mar 27, 2012 12:37 am
Offline
Professional Musician
Professional Musician

Joined: Fri Jun 26, 2009 6:53 pm
Posts: 2252
Location: Harvard IL
CID, http://www.tubesandmore.com should have what you need. BTW what does esak mean? Art

_________________
None of Us are free, if One of Us is chained !


Top
Profile
Post subject: Re: Champ amp parts location help AA764 cap kit
Posted: Tue Mar 27, 2012 11:04 am
Offline
Hobbyist
Hobbyist

Joined: Mon Mar 26, 2012 10:31 am
Posts: 2
bad spelling on my part should read esr reading for caps ( in circuit cap reader)

thanks for all the help
Carl
thanks art and arjay


Top
Profile
Post subject: Re: Champ amp parts location help AA764 cap kit
Posted: Tue Mar 27, 2012 12:08 pm
Offline
Rock Star
Rock Star
User avatar

Joined: Sat Jul 03, 2010 2:18 pm
Posts: 6544
I take it your ESR meter reads that each section of the can had much higher than nominal resistance. Pretty sure your can (well not "your" personal can, but the amp's--- :lol: ) is pretty much dried up. You pull these cans and notice a considerable difference in weight between the old and a new one.

I've been using FP and JJ cans (available from Antique Electronics) for some time now. Both are good. JJ requires a mounting clamp for the chassis. One little blurb. I've always ramped up new or old cap cans, on first fire-up. One of my pecadilloes.

One, to check for shorts. And two, I have yet to have a pre-mee failure in any can I ramped up over a few hours ( usu 3-5). First, be sure you have a direct heated rectifier in the amp (just for this process----such as a 5U4GB in place of an OEM 5AR4/GZ34--- the new can must "see" voltage from zero on up). All power tubes in. Crank the bias to full CCW (all the way "cold"). Speaker(s) connected. No input. Zero volume.

With a Variac between wall outlet and amp, I first set the voltage to around 60VAC. Check for obivous shorts, bad connection. Measure the PS rail (each tap off point: to output tubes, to gain stages, to EFX/tone control tubes, to input tubes). The voltages won't be equal to what is on the schematic. BUT, you should have the relative drop in voltage across each subsequent tap. If the volt don't have a relative drop like they should---say the schemo reads 472, 465, 425, 305 for each tap. You should see similar drop across the taps, just lower voltage with respect to the lower volts being supplied by the Variac (like say, 250, 245, 225, 205)--- turn off the Variac and start looking for mis-wiring, inadvertent shorts, etc.

ANYHOO... ramping up really anneals or forms the cap in a nice gentle manner. And these caps tend to last longer and are quieter, than ones which are plugged right into the wall and pegged from the get-go.

I have recapped quite a few Champs, VC, and Princetons.. as well as Hiwatts and Ampegs this way, even with NOS cap cans (which many say is a no-no). Worked out preety well.

Just my experience. Yours may vary. But, I think most ppl would agree, careful double checking of work while changing the PS parts can pay off in a stone cold reliable unit. Being in too much of a hurry can lead to an early 4th of July. :shock:

Good luck!


Top
Profile
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 5 posts ] 

All times are UTC - 7 hours

Fender Play Winter Sale 2020

Who is online

Users browsing this forum: No registered users and 2 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum

Search for:
Jump to: