It is currently Mon Mar 16, 2020 10:03 am

All times are UTC - 7 hours



Post new topic Reply to topic  [ 3 posts ] 
Author Message
Post subject: 68 custom twin reverb... Needs help...
Posted: Fri Feb 15, 2019 1:25 pm
Offline
Hobbyist
Hobbyist

Joined: Fri Feb 15, 2019 1:01 pm
Posts: 2
Have a 68 custom twin reverb that has multiple issues and need some help. There is a couple resistors that are toast and I have no way of knowing the values to replace. I know everyone says to use the 65 twin reissue schematic for the 68 custom but they don’t match up on values in a lot places in this thing. So I need a real schematic for this amp or someone to put eyes on what’s in their amp. The resistors that I need to know the values of are R67,R68. Any help would be great, as fender doesn’t deem it worthwhile to give me a reply to my support requests. Thanks all...


Top
Profile
Fender Play Winter Sale 2020
Post subject: Re: 68 custom twin reverb... Needs help...
Posted: Tue Feb 19, 2019 11:17 am
Offline
Professional Musician
Professional Musician

Joined: Thu Aug 07, 2014 3:25 pm
Posts: 1023
I would expect r67 and 68 to be the same as the 65 Twin schematic. This is part of the power supply. Its a foundation circuit, not associated with tone or features.
Their values of 1k and 4.7k are probably accurate.
The F.P. designation means flameproof coating. This type of resistor is designed to act as a fuse when overloaded. The 1 watt designation is actually a 1/2 watt resistor rated for 1 watt. So they look small for the job. You can find them at Mouser.
When these types blow, the color codes are gone. You can measure the approximate value by scraping the body of the resistor down past the burnt coating to the spiral resistance element.
Looking with magnification, you can see the point where the spiral is blown. With an ohm meter, measure both ends to the leads. Add these together to approximate the original value.
Find the reason these resistors blew before replacing them. Look for shorted preamp tubes.


Top
Profile
Post subject: Re: 68 custom twin reverb... Needs help...
Posted: Tue Feb 19, 2019 5:48 pm
Offline
Hobbyist
Hobbyist

Joined: Fri Feb 15, 2019 1:01 pm
Posts: 2
Thanks for the info. I did end up using the 65 schematic values. This thing has been a nightmare since new. Eating tubes, noise, toasting componets. So just finished doing a total cap job. And also took negative feedback section back to the 65 reissue specs. I have to say was best choice I made with it. Before had so much idle noise couldn’t stand to be in same room with it and forget even trying to record with it. Now sounds great compared to what it was. And a note to anyone having trouble with their reverb howling and such. Pull the jack for the foot switch and grind/sand the inside of the chassis so it grounds properly. I also pulled every pot and jack and used a Dremel to clean the chassis on every hole. Once again thanks for the info..


Top
Profile
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 3 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: