It is currently Mon Mar 16, 2020 7:17 pm

All times are UTC - 7 hours



Post new topic Reply to topic  [ 5 posts ] 
Author Message
Post subject: Frontman Reverb noise
Posted: Sat Mar 28, 2015 12:21 pm
Offline
Hobbyist
Hobbyist

Joined: Thu Mar 20, 2008 5:21 pm
Posts: 3
I just got hold of a used Frontman Reverb. After a quick cleanup, it was working fine except for the reverb, which only produced a hum. Snugging down the reverb connections to the main board took care of that, but now it produces a hissing/crackling noise.

Here’s what I’ve observed:

1. The noise appears whether a cable is plugged in or not.
2. The noise is independent of volume, and appears even when the volume is at zero.
3. The noise is audible through headphones.

Any suggestions for this?

Thanks.


Top
Profile
Fender Play Winter Sale 2020
Post subject: Re: Frontman Reverb noise
Posted: Sat Mar 28, 2015 7:25 pm
Offline
Professional Musician
Professional Musician

Joined: Thu Aug 07, 2014 3:25 pm
Posts: 1023
Could you be a little more specific about the model 212R.....25R
My first guess is input jack with broken solder


Top
Profile
Post subject: Re: Frontman Reverb noise
Posted: Sun Mar 29, 2015 7:38 am
Offline
Hobbyist
Hobbyist

Joined: Thu Mar 20, 2008 5:21 pm
Posts: 3
TimsAudio wrote:
Could you be a little more specific about the model 212R.....25R
My first guess is input jack with broken solder


The front panel simply says “Frontman Reverb,” but there is a model number on the back, “PR-421.” A little looking around tells me that it is apparently identical to a Fender Bullet Reverb.

I would have thought that if the problem were with the input jack then the noise level would be affected by the volume knob, which this isn’t.


Top
Profile
Post subject: Re: Frontman Reverb noise
Posted: Sun Mar 29, 2015 8:49 am
Offline
Professional Musician
Professional Musician

Joined: Thu Aug 07, 2014 3:25 pm
Posts: 1023
You're right, the input jack normally wouldn't have anything to do with it. But on some models of Frontman, there is a muting circuit that engages when there is nothing plugged in to it. The amp is very quiet until you plug in. Then when the circuit unmutes, its very hissy.
That's why I asked about the specific model. Your's doesn't have this feature.
The tone controls and the channel switch are downstream of the volumes. Cleaning and inspection are the first approach.
So check over the solder on the controls and the power output IC.
Look closely at the back of all the controls. If its the style I think it is, they are prone to damage from pushing sideways on the knob too hard.
There should be a little black nubbin sticking out the center of the back. It provides centering for the wiper of the control. It breaks easily and the control will go intermittent. Sometimes it will not fall out by itself, but check that the nubbins all rotate with the knob
Then look at the brown plastic on the back of the controls for cracks. This is the substrate that the resistance element is printed onto. Pushing too hard on the knob can break this and the control will act funny or not work at all.
If that doesn't help, look over the soldering for cracks.


Top
Profile
Post subject: Re: Frontman Reverb noise
Posted: Sun Mar 29, 2015 8:55 am
Offline
Hobbyist
Hobbyist

Joined: Thu Mar 20, 2008 5:21 pm
Posts: 3
TimsAudio wrote:
You're right, the input jack normally wouldn't have anything to do with it. But on some models of Frontman, there is a muting circuit that engages when there is nothing plugged in to it. The amp is very quiet until you plug in. Then when the circuit unmutes, its very hissy.
That's why I asked about the specific model. Your's doesn't have this feature.
The tone controls and the channel switch are downstream of the volumes. Cleaning and inspection are the first approach.
So check over the solder on the controls and the power output IC.
Look closely at the back of all the controls. If its the style I think it is, they are prone to damage from pushing sideways on the knob too hard.
There should be a little black nubbin sticking out the center of the back. It provides centering for the wiper of the control. It breaks easily and the control will go intermittent. Sometimes it will not fall out by itself, but check that the nubbins all rotate with the knob
Then look at the brown plastic on the back of the controls for cracks. This is the substrate that the resistance element is printed onto. Pushing too hard on the knob can break this and the control will act funny or not work at all.
If that doesn't help, look over the soldering for cracks.

I will have a look at these. Thanks very much.


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: