Yikes! :siren:

76Trans Am · Post by **76Trans Am** » Sun Jul 12, 2009 4:12 pm

Ok,
So, I was doing some amp testing today...
Verify working condition and a bit of SQ listening..
First amp up was the ZPA 0.3 I just got,
Fired it up everything was fine and sounded great.
Did a few other amps and was going back to the ZPA
And when I hooked up the power to it I got a puff of smoke from one of the caps and things started to glow.
I quickly removed the power and checked all my connections
Everything was fine.
Hit power to it again and the same cap started up again.

So I guess this one is ready for a cap replacement.
Does it damage anything else if you catch it quick?

This sucks...I just got this amp

Think I should hit the seller up about this?

Thanx,
Jeff

Post by **Jacampb2** » Sun Jul 12, 2009 5:54 pm

Bad caps can do other damage. in some cases very serious damage if it was not found in a reasonable amount of time. Whether or not there is collateral damage on your amp is unknown. The somewhat ambiguous answer is it is certainly possible and possible that there is not. You will have to check it thoroughly.

Should you hit the seller up? IMO, no, not unless it was sold as already having had the caps replaced. If they are original, and no one told you otherwise, then it is a crap shoot when they are going to go. The amp is a minimum of 10 years old, wet caps have a finite life span, both in cycles, and as in shelf life. A new old stock cap that has sat on a shelf for 10 years can be just as bad as one that has been in circuit for ten years. If you had asked any of us on here, we would have recommended cap replacement regardless of if there were any early signs.

Small wet caps tend to last much longer than their larger brothers. What cap shorted on you? The typical problem areas are the power supply input caps (high likelihood of problems) and the rail caps (lower likelihood, but still possible). If it were any of the little bypass caps or other small wet caps, then I would suspect there is more wrong with the amp then just a bad cap.

Good luck,
Jason

76Trans Am · Post by **76Trans Am** » Sun Jul 12, 2009 6:17 pm

I was right there when it started and killed power right away.
It was one of the 16v 2200Uf caps.
I have taken the covers off and inspected the board.
I see no visible damage.

Looks, Like I will be ordering a few...
I have another 0.3 a 0.5 and 2 MS 275's

So, I should replace all of the large caps?
Bigger is better right? as long as they fit and have the temp rating.

Post by **ttocs** » Sun Jul 12, 2009 6:38 pm

yes you will want to replace them all.

76Trans Am · Post by **76Trans Am** » Sun Jul 12, 2009 7:35 pm

Ok,
I was thinking of replacing the 16V 2200Uf caps with these.
http://search.digikey.com/scripts/DkSea ... 93-1545-ND

And the 35V 4700Uf with these.
http://search.digikey.com/scripts/DkSea ... e=P6658-ND

What do you think ?

Post by **Jacampb2** » Sun Jul 12, 2009 8:28 pm

There is no reason to go with a higher Working Voltage cap. Stick with the same WV, and find higher capacitance. The second ones you show are 22mm diameter, probably a bit too large.

Take a look at these, I just bought a shed load of them for my ZPA0.8 projects and I am happy with them, as well as the price. Nichicon Radial Aluminum Electrolytic Capacitors - 105 Degree 10000uF 16V 105c 18x35.5 20% 7.5LS

Make sure you pay close attention to the height and diameter, The above caps worked in my project, but I built a custom case, so I had more room to work with.

So, short answer, use the largest caps (in uF) that you can afford that will fit in the allowed footprint. Use the same WV or higher, but there is no benefit in going to a higher WV if the original engineers did their job correctly. Use the same or better temperature range, specifically watching the high end of the range for our purposes. For PS input caps, IMO, there is not much more to be concerned with.

Later,
Jason

76Trans Am · Post by **76Trans Am** » Sun Jul 12, 2009 8:53 pm

The second ones are for replacing the 6 other large caps in the amp. (Rail caps ?)

The originals are 35V 4700Uf and the larger size.

76Trans Am · Post by **76Trans Am** » Mon Jul 13, 2009 7:49 pm

Or do you think these would be a better replacement for the rail caps.
Stock are 35V 4700Uf

http://mouser.com/Search/ProductDetail. ... IQnTlhM%3d

LMK What ya think.

Thanx.

76Trans Am · Post by **76Trans Am** » Wed Jul 29, 2009 6:11 pm

Ok Repair guru's
I received the new caps today and replaced them in this ZPA 0.3
Now when it powers up the thermal light comes on.
If I brush my finger gently on the back side of the two vertical boards next to the crossover slot I get some pops thru the speakers.

If I catch it just right it will switch from thermal to power on.
It plays great once it is on.
But if I power down, and reconnect it goes back to thermal.
What do I check?

Thanx,
Jeff

knightrider358 · Post by **knightrider358** » Wed Jul 29, 2009 6:13 pm

sound like something is loose maybe a thermal sensor or something that deals with that