Question about White Oak bulk storage caps.

[Wayne G.]

I see on the WO website they offer (for the PL400) pwr supply caps ranging from 13,600 mf 100v to 18,800 mf. What would you
consider when choosing one capacity over another? Also do these need to be formed prior to install or are they good as received.
My PL400 has the orig. 5900 mf 85v units held in with the double sided foam tape. They both test ok. Is this a worth while upgrade?

 

[Northwinds]

There is no substitute for cubic inches and that holds true with reseve capacity power. Bigger is better and only a few bucks more!

 

[laatsch55]

Yes, those caps are old . They are subject to failure at any time, and the electrolyte is drying out...

 

[NavLinear]

Wayne,

The power supply capacitors are old and age tends to be a problem with electrolytic caps. One of my PL 400s had the double sticky tape holding them in place and when I removed them I also removed the tape. I installed the 18,000 uF caps and used the included WO bracket with fastener to hold the new ones in place. If you do replace these capacitors I would recommend the higher capacity ones. Another consideration would be replacing the full wave bridge rectifier. The surge current increases with larger capacity capacitors and replacing the BR with a new one rated at 25 or 35 amps (@400 V or so) is commonly done. One other recommendation with this upgrade/modification is to add snubber caps across the four diodes. I believe that an optimal value for this is 0.022 uF and you'll want a rating of about 400 V or so.

This is one of the easiest upgrades you can do - just remember to take photographs before you start and carefully label any wires you remove/desolder and all should work out well.

BTW - The capacitors from White Oak are preformed and measured for leakage so they are ready to be dropped in place and put to work.

Nav

 

[laatsch55]

What he said....

 

[Northwinds]

The Naughty Nurse rules

 

[premiumplus]

The Naughty Nurse rules

Ain't nuthin' naughty about nurses noway, 'specially NavLinear's...

 

[Wayne G.]

Wayne,

The power supply capacitors are old and age tends to be a problem with electrolytic caps. One of my PL 400s had the double sticky tape holding them in place and when I removed them I also removed the tape. I installed the 18,000 uF caps and used the included WO bracket with fastener to hold the new ones in place. If you do replace these capacitors I would recommend the higher capacity ones. Another consideration would be replacing the full wave bridge rectifier. The surge current increases with larger capacity capacitors and replacing the BR with a new one rated at 25 or 35 amps (@400 V or so) is commonly done. One other recommendation with this upgrade/modification is to add snubber caps across the four diodes. I believe that an optimal value for this is 0.022 uF and you'll want a rating of about 400 V or so.

This is one of the easiest upgrades you can do - just remember to take photographs before you start and carefully label any wires you remove/desolder and all should work out well.

BTW - The capacitors from White Oak are preformed and measured for leakage so they are ready to be dropped in place and put to work.

Nav

Many thank guys, I am on it. Will be ordering those today. My ex wife was a nurse but did not look like yours!

 

[Wayne G.]

Ok, got the kit from bulk storage cap kit (18,600mf) got it installed (no issues at all). Seems a really big difference in low frequency output. Much more robust low end. Low frequencies can now keep up with or match highs as volume goes up perhaps a little cleaner throughout. What a great upgrade.

 

[laatsch55]

Done the driver board and backplanes yet??

 

[Wayne G.]

Done the driver board and backplanes yet??

No sir not yet, I had just had the whole thing rebuilt recently, he replaced almost everything on the driver board, all the output transistors
everything but the bulk storage caps which he said tested "good". I still plan on this at some point however, the PL4000 has to be sorted out next.
Buy the way how much approximately are your suggested upgrades Lee?

 

[laatsch55]

I think the backplane boards are 125 a set with all components, you have to assemble that. The "D" driver board is 175.00 fully assembled and tested...plus 14.00 if the 1304's and 05's are not available for salvage...