[GanjaTron]

Hi everyone,

quick question. Maybe it's just me, but I could swear my Crimson recently emits a smell reminiscent of burnt paper.  It does so just minutes after powering up, and it's gotten quite intense to the point where I had to shut it down.

Note I don't actually see any smoke, and maybe my nose is even playing tricks on me, but there's the nagging doubt...

I'm suspecting the two metallised paper RIFA filter caps on the Power One PSU's primary board. I thought I replaced these when I refurbished the PSU, but the piccies I took as records don't confirm this (I definitely replaced them in my PowerSeries, tho). I've seen a lot of these caps blow recently, and really should have known better back then. Nowadays I replace them outright, cracked or not.

Has anybody had issues with these caps in their PSUs, or should I be looking at something else? I'm really reluctant to haul this thing out from under my desk and spend weeks dismantling it again, only to find nothing amiss...

Thanks  for any hints. Have a good weekend,

--Roland

[robespierre]

I did have a similar experience with a deskside Power Series. Yes, the metallized paper "Rifa" capacitors are almost certainly the cause of the smell.
They can let off sparks or explode too, but they don't always do it.

[GanjaTron]

Hi Robespierre,

Thx for the feedback. I take it that's the Power Series marked "past" in your sig.

I've never experienced a "passive smoker" RIFA, most just blew up outright. I suppose it depends on the circuit (X or Y), with X being by far the more problematic.

The most spectacular instance was in a Grundig VCR PSU; this thing was LOUD! The cap sent shrapnel flying inside the (shielded) PSU, and actually made a dent in the shielding. Incredibly, the force of the blast even catapulted the fuse -- located immediately adjacent to the cap -- right out of its socket! It was a PITA to clean up; the PSU was littered with metallised paper flakes, plus the usual flame retardant gunk covering all the components.

Ok, so it looks like I have yet another project to keep me busy me over the Xmas break...  

--Roland

[robespierre]

At the time I had a Rifa experience with the 4D, I didn't know as much as I do now. Today I probably would have fixed it instead of trading it away (it was not scrapped).
When I tried taking the power supply (an ACDC unit) apart, I couldn't find any vented capacitors. But I was not specifically looking for metallized paper, and I didn't check inside the inlet filter (which may have been a Schaffner for all I know).
The odor was very strong, redolent of about a pound worth of burning hair. It also was very "sticky" and stayed in the corner of the room for over a month after power was removed.
The machine kept running and probably would still have started if I could have handled the smell.

[jan-jaap]

If it vaguely smells like dead fish you may have capacitors leaking their bodily fluids all over your PCBs...

It's hard to explain, but once you've smelled it you'll recognize it.

[GanjaTron]

If it vaguely smells like dead fish you may have capacitors leaking their bodily fluids all over your PCBs...

It's hard to explain, but once you've smelled it you'll recognize it.

Hi JJ,

I'm familiar with it. Been there, done that. I replaced the electrolytics in that thing long ago. Smell definitely more like burnt paper.

I also had a Schaffner IEC mains filter spectacularly blow in my HP Apollo. Instead of a single pop, it let loose a sustained barrage of orange firecrackers under my desk. I was about to grab the fire extinguisher, expecting the rug to catch fire. This was way beyond what I'd experienced with RIFAs, tho I guess it's pretty much the same failure process. Getting a replacement was quite a challenge, as the original part was unusually compact.

--Roland

[vishnu]

I've had a few electrolytics that have blown up over the years, the small ones (15 or so microfarads) go off like firecrackers, the big ones (300 or so microfarads) go off like grenades. Neither is fun...

[GanjaTron]

Well, I dragged it out from under the desk and popped the back off. Peering through the PSU's vents, it's now clear I _did_ replace the Y caps on the primary board with film caps, so I wasn't quite as sloppy as I thought I was.

I let it run for almost 1 hour while periodically sticking my nose in the PSU, and installed patch 1550 while I was at it to finally get my RE textport back. Lo and behold: didn't smell anything funny. That said, I ran it directly off the outlet rather than the power strip all the other crap is on.

So either the power strip and/or cable is dodgy (the extension does get pretty warm), or it's kicking up some crusty dust from under the desk. Maybe I should stick air fresheners inside?