It is currently Mon Mar 16, 2020 10:51 am

All times are UTC - 7 hours



Post new topic Reply to topic  [ 41 posts ]  Go to page Previous  1, 2, 3
Go to page Previous  1, 2, 3
Author Message
Post subject: Re: Pro Reverb (pulling my hair out!)
Posted: Wed Aug 10, 2016 4:34 pm
Offline
Amateur
Amateur

Joined: Sat May 25, 2013 10:02 pm
Posts: 197
Installed new Russian 5AR4 and no fuse blow. But, at same time i unscrewed and lifted the small board that the 100v/100uf bias capacitor is mounted on. Is the wire coming off the positive side of that Cap NOT suppose to touch the chassis? it looks like it mounts to a screw on the chassis.


Top
Profile
Fender Play Winter Sale 2020
Post subject: Re: Pro Reverb (pulling my hair out!)
Posted: Wed Aug 10, 2016 5:33 pm
Offline
Amateur
Amateur

Joined: Sat May 25, 2013 10:02 pm
Posts: 197
Amp is running!!!! Set bias at 25MA (it was reading 52!!) not drifting....Fingers crossed!


Top
Profile
Post subject: Re: Pro Reverb (pulling my hair out!)
Posted: Wed Aug 10, 2016 6:00 pm
Offline
Rock Star
Rock Star
User avatar

Joined: Sat Jul 03, 2010 2:18 pm
Posts: 6544
Congrats!!! :D
Yes, there should be two circuit boards. One to solder the components and one below to keep the wiring from touching the chassis.

Your best bias point should be around 35-40mA per tube. The assumed plate voltage ~ 450-475VDC with a healthy GZ34.


Top
Profile
Post subject: Re: Pro Reverb (pulling my hair out!)
Posted: Wed Aug 10, 2016 6:08 pm
Offline
Rock Icon
Rock Icon
User avatar

Joined: Wed Mar 31, 2010 12:48 am
Posts: 26416
Location: Tombstone Territory
BMW2002Ti wrote:
The assumed plate voltage ~ 450-475VDC with a healthy GZ34.


440 VDC for the AA165, 437 VDC for subsequent revisions (excluding the UL variant).

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: Pro Reverb (pulling my hair out!)
Posted: Wed Aug 10, 2016 6:13 pm
Offline
Rock Star
Rock Star
User avatar

Joined: Sat Jul 03, 2010 2:18 pm
Posts: 6544
Arjay,

Those values include today's increased outlet voltages?

Thanks!


Top
Profile
Post subject: Re: Pro Reverb (pulling my hair out!)
Posted: Wed Aug 10, 2016 8:32 pm
Offline
Rock Icon
Rock Icon
User avatar

Joined: Wed Mar 31, 2010 12:48 am
Posts: 26416
Location: Tombstone Territory
They are the published specs found on the original schematics.

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: Pro Reverb (pulling my hair out!)
Posted: Wed Aug 10, 2016 8:44 pm
Offline
Amateur
Amateur

Joined: Sat May 25, 2013 10:02 pm
Posts: 197
You guys might like this ending...when placing the chassis back into the cabinet (old style with screen on the inside as the ground, one of the strands 1/2" was sticking down, and as I slid chassis in it could see it was going to touch the lug of the power switch, could this have taken out my fuse in the first place?


Top
Profile
Post subject: Re: Pro Reverb (pulling my hair out!)
Posted: Wed Aug 10, 2016 8:49 pm
Offline
Rock Star
Rock Star
User avatar

Joined: Sat Jul 03, 2010 2:18 pm
Posts: 6544
Could be. Never heard of that. I have replaced some which were torn to shreds, but apparently not touch live circuitry.


Top
Profile
Post subject: Re: Pro Reverb (pulling my hair out!)
Posted: Wed Aug 10, 2016 9:09 pm
Offline
Rock Icon
Rock Icon
User avatar

Joined: Wed Mar 31, 2010 12:48 am
Posts: 26416
Location: Tombstone Territory
I've had that screen-mesh RF shielding do that a time or two during my career. Use scissors to cut away the offending strands.

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: Pro Reverb (pulling my hair out!)
Posted: Wed Aug 10, 2016 10:55 pm
Offline
Amateur
Amateur

Joined: Sat May 25, 2013 10:02 pm
Posts: 197
Ahhhhh....so it can happen? Wow! I did take tiny wire cutters and trimmed it back just for safety.

Thanks for all the great conversation on this one.


Top
Profile
Post subject: Re: Pro Reverb (pulling my hair out!)
Posted: Wed Aug 10, 2016 11:23 pm
Offline
Rock Icon
Rock Icon
User avatar

Joined: Wed Mar 31, 2010 12:48 am
Posts: 26416
Location: Tombstone Territory
My "career" spans about fifty years and I've only seen it twice. So it's pretty rare. I do make a point of inspecting that screen anytime I open up a vintage Fender amp -- mine or a client's. Just in case......

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
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 41 posts ]  Go to page Previous  1, 2, 3
Go to page Previous  1, 2, 3

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: