Electrolytic Cap replacement in old pro mixer PSU

[oc disorder]

Hi

I have a power supply with 6 x Philips PCB mounting 10,000uF 40v cap which need replacing.
As I am poised with a drill over a double sided 3mm thick PCB a moment of doubt crept into my mind
like it would with a router poised over a '59 Strat!
The Philips caps have 5 prongs or solder tabs 2 for the connection and an additional 3 that go to isolated
pcb pads for mounting stability.
"They don't make them like they used two"!
The spacing for the original active pins is approx 25 mm wheras the modern replacement snap in type
spacing is approx 10 mm.
As far as I can tell the through plating is still intact after wrestling with hot irons, solder suckers
and solder wick .. no I don't have the luxury of a vacuum solder station.
I would like to do this as neatly as possible and figure I have two choices assuming that the original type
of cap/mounting is no longer available.
It was assembled in '94.
Choice one is to secure one terminal (maybe ground ? ) in one hole and 10 mm away in a vacant space,
drill a hole allowing me to connect back under the board to the original pad with a large jumper -no kangaroo jokes please !
Choice two - as the new ones are shorter, is to make up a small vero board adapter for each cap with
two pins in the exact position of the pcb layout .
This may require bucket loads of hot melt glue!
Any suggestions welcomed.
It is one of two supplies to power a 48 channel desk which has spent more time powered up since it was made-
rather than powered down!
Of course while the supply is out of service the studio cannot operate so its also a rush job :-(
which makes choice 1 attractive.
As I write this the replacements are being "air bagged" to me.

I am hoping another tech has already "been there - done that" .

[Enzo]

Caps have indeed shrunk over the years. So your new 40v caps have smaller spacing on the leads. WHat if you looked at 63v caps? Maybe find some larger ones? And how many of those 6 caps are in parallel? Two sets of three? Three sets of two? Other? Instead of replacing two parallel 10,000uf caps, perhaps look for a single 20,000uf cap, or even larger.


Having serviced many older PV power boards from the 1980s, they used these large blue can caps, which became obsolete. So instead of the 5000uf 55v can caps with solder tabs, they now send 4700uf 63v snap-ins. Exactly what I would have chosen for myself. The leg spacing doesn;t fit the trace art, so I do indeed drill new holes. I can reuse one hole and drill just one new one for the cap. Always be careful what you are drilling through. Especially on two-sided boards. The PV boards were one sided.

Option 3 - use contact cement to glue the new caps upside down to something, and run wires back to the pc board from their upturned legs.

[oc disorder]

Hi Enzo and thanks.

I have ordered some 63v caps. The spacing is a little strange and not symmetrical.
I do have a 100v version and that also has 10mm spacing.
The tracks underneath luckily are the same potential as the top ones hence the through plating on the holes.
Probably worth building a spare to avoid down time although it also has a 5v rail with remote sensing .
As usual the main aim is for a clean supply not a work of art on the board that no one will see except for the next tech!!!

As long as I use heavy gauge wire I don't think the supply will notice the difference.!
Cheers and good to see you back on deck .
Regards
O.C.

[jrfrond]

Very often, older gear will require creative retrofitting and perhaps a bit of "reptile dentistry" to repair. You have to do what you have to do.

[diagrammatiks]

they still make 5 pin caps.

kemet bhc has them as an option.