ARS filter capacitors...

[lespaul6]

there are six of these on the plexi reissues- has anyone ever experienced the tops of the two closest to the power tubes warping from the heat of the tubes? If you press the warped plastic top down the actual top of the capacitor is flat, just the plastic top is warped from what looks like heat (tubes were pulling 50ma of current when I checked it lol)

 

[LP Freak]

That's not caused by the heat of the tubes. That's a sign that your caps are going bad and need to be replaced.

 

[H3000]

Filter cans vent and blister on the ends of the filter can where the terminals are located they do not vent on the other end. if the actual metal chassis of the filter can was bulging you would have a problem but if the can is flat under the plastic then its not venting just heat has distorted the plastic.
venting can be seen as a small raised dome on the black disc at the end of the can where the terminals are located on the end of the can that is inside the amp. the small raised dome that appears is the actual vent bulging hence the name venting

 

[lespaul6]

yes... I thought that might be the case as Ive only seen them blow from the bottom as well. anyone have pics of their can caps blowing from the top??

 

[H3000]

yes... I thought that might be the case as Ive only seen them blow from the bottom as well. anyone have pics of their can caps blowing from the top??

Not seen one in 38 years of owning marshalls....its always the the vent on the bottom of the can starts venting/bulging,
The vent by the terminals is there for a good reason and it actually works as an indicator of failiure and if the vent bulges then it should not be ignored but plastic on the top of the can is just heat causing air to expand and stretch the thin plastic which has become soft and pliable/stretchy with the heat and then when it cools the plastic stays in the dome shape, if the can under the plastic is flat its fine .. but if it it makes you feel safe then you could always change it

 

[lespaul6]

yes... I thought that might be the case as Ive only seen them blow from the bottom as well. anyone have pics of their can caps blowing from the top??

Not seen one in 38 years of owning marshalls....its always the the vent on the bottom of the can starts venting/bulging,
The vent by the terminals is there for a good reason and it actually works as an indicator of failiure and if the vent bulges then it should not be ignored but plastic on the top of the can is just heat causing air to expand and stretch the thin plastic which has become soft and pliable/stretchy with the heat and then when it cools the plastic stays in the dome shape, if the can under the plastic is flat its fine .. but if it it makes you feel safe then you could always change it

thanks again!

 

[SLOgriff]

I concur. My 2002 Bogner Rev2 has ARS filter caps. The tops are raised up(bubbled) a little as well but the amp sounds fantastic. I was concerned so I called Bogner. Charlie said they were fine and should have many years left on them. I also called ARS and talked to the owner I think. Told him the amp I had and the year as well as the bubbled up plastic parts on top.....he said it was nothing to worry about and those caps are high quality and should last 15-20 years.

There is a lot of misinformation out there. Best to talk with the experts. All is well and just heat causing the plastic to pucker a little.

 

[lespaul6]

Awesome guys.. thanks for the replies, may help someone else in the future! Some techs might take advantage of this lack of knowledge

 

[hopkinWFG]

Mmmm but ARS are merely rebranded capacitors... same as what they did for their tubes. perhaps a good leakage test, and good screening over the bad caps..?

 

[lespaul6]

Need an ERS meter right?

 

[TrueTone500]

Some filter capacitors appear bubbled on the top due to the wrap constricting the plastic disc that covers the top of the capacitor. If you push the top down, and it doesn't give like you're pushing a button, then it's probably a bulging can. If you want to be able to inspect the can visually, just remove the plastic disc.

Tip: If you're doing your own solder work, don't use tap water on your cleaning sponge. Tap water contains dissolved solids (calcium/lime) which can contaminate the solder causing noise and cold-joints. Use distilled water only.