8 Sep
2019
8 Sep
'19
4:42 p.m.
Has anyone replaced the capacitor in a ferroresonant power supply with much
success? My current understanding is that the capacitor and transformer are
mated as a pair, so replacing just one of them would require careful
consideration.
The PDP-8/I I'm working on has a 704A in it, with a GE 8uF 660V capacitor.
It measures a couple of nF on my capacitor meter, and I was told by the
previous owner that it's dead.
Any advice?
Thanks,
Kyle
8 Sep
8 Sep
4:54 p.m.
Hi Kyle,
On Sun, 8 Sep 2019 18:42:06 -0500
Kyle Owen via cctalk <cctalk at classiccmp.org> wrote:
Has anyone replaced the capacitor in a ferroresonant
power supply with much
success? My current understanding is that the capacitor and transformer are
mated as a pair, so replacing just one of them would require careful
consideration.
The PDP-8/I I'm working on has a 704A in it, with a GE 8uF 660V capacitor.
It measures a couple of nF on my capacitor meter, and I was told by the
previous owner that it's dead.
We recently replaced the ferroresonant capacitor in a power supply on the CHM's
PDP-1. They do fail (thankfully, not often) - and they are not super-critical
as to value. If the one you're replacing has the same marked value, you should
be fine.
Cheers,
Lyle
PDP-1 Restoration Team, CHM
--
73 NM6Y
Bickley Consulting West Inc.
https://bickleywest.com
"Black holes are where God is dividing by zero"
6:38 p.m.
At 04:54 PM 8/09/2019 -0700, you wrote:
Hi Kyle,
On Sun, 8 Sep 2019 18:42:06 -0500
Kyle Owen via cctalk <cctalk at classiccmp.org> wrote:
Yes, that's right. Find something with the same marked capacitance value.
The rated voltage can be the same or higher.
Be aware these are non-polarized caps, NOT electrolytics. They are typically
paper, foil and oil. Best to find a new replacement, as many old-old oil-
insulated caps will contain PCB (polychlorinated biphenyl) oil, which is
severely carcinogenic. Banned, and must be disposed of as contaminated waste.
Guy
Has anyone replaced the capacitor in a
ferroresonant power supply with much
success? My current understanding is that the capacitor and transformer are
mated as a pair, so replacing just one of them would require careful
consideration.
The PDP-8/I I'm working on has a 704A in it, with a GE 8uF 660V capacitor.
It measures a couple of nF on my capacitor meter, and I was told by the
previous owner that it's dead.
We recently replaced the ferroresonant capacitor in a power supply on the CHM's
PDP-1. They do fail (thankfully, not often) - and they are not super-critical
as to value. If the one you're replacing has the same marked value, you should
be fine.
Cheers,
Lyle
PDP-1 Restoration Team, CHM
7:41 p.m.
On Sun, Sep 8, 2019, 20:39 Guy Dunphy via cctalk <cctalk at classiccmp.org wrote:
I can't seem to find motor caps that meet the voltage spec of 660V. 8uF
doesn't seem like a problem, but the combination together isn't looking
good. Are there any specific vendors I should be looking at? My usual
suspect of DigiKey isn't looking good.
Thanks!
Kyle
We recently replaced the ferroresonant capacitor in a power supply on the
CHM's
PDP-1. They do fail (thankfully, not often) - and
they are not
super-critical
as to value. If the one you're replacing has
the same marked value, you
should
be fine.
Yes, that's right. Find something with the same marked capacitance value.
The rated voltage can be the same or higher.
8:54 p.m.
On 9/8/19 7:41 PM, Kyle Owen via cctalk wrote:
I can't seem to find motor caps that meet the
voltage spec of 660V. 8uF
doesn't seem like a problem, but the combination together isn't looking
good. Are there any specific vendors I should be looking at? My usual
suspect of DigiKey isn't looking good.
What capacitance do you require? For motor start/run capacitors, I
tend to stay away from Chinese ones--they just don't seem to last.
Try googling for "660VAC capacitor". They don't seem to be terribly
difficult to find. Amazon even sells them.
--Chuck
10 Sep
10 Sep
8:18 a.m.
On 9/8/2019 9:54 PM, Chuck Guzis via cctalk wrote:
On 9/8/19 7:41 PM, Kyle Owen via cctalk wrote:
Try here.
http://www.surplussales.com/
I can't seem to find motor caps that meet the
voltage spec of 660V. 8uF
doesn't seem like a problem, but the combination together isn't looking
good. Are there any specific vendors I should be looking at? My usual
suspect of DigiKey isn't looking good.
What capacitance do you require? For motor start/run capacitors, I
tend to stay away from Chinese ones--they just don't seem to last.
Try googling for "660VAC capacitor". They don't seem to be terribly
difficult to find. Amazon even sells them.
--Chuck
8:44 a.m.
It's good that these caps are so readily available.
But on the other hand, I don't have any sort of power supply
at all, for either of my two PDP 8/S machines. Sob.
Being in a 240VAC mains country doesn't help, since I understand
the original DEC supplies were 110VAC input only.
But I'm not complaining. It's an easy problem to solve, once I get to it.
Guy
8 Sep
8 Sep
9:18 p.m.
m?ndag 9 september 2019 skrev Kyle Owen via cctalk <cctalk at classiccmp.org>:
On Sun, Sep 8, 2019, 20:39 Guy Dunphy via cctalk
<cctalk at classiccmp.org>
wrote:
Mouser has CDE 8 uF 660 VAC. 11 are on order from the manufacturer.
https://www.mouser.se/ProductDetail/Cornell-Dubilier-CDE/SFA66T8K475B-F?qs=…
I have replaced several of these capacitors in PDP-8, LA30, PDP-9.
/Mattis
>
>We recently replaced the ferroresonant capacitor in a power supply on
the
CHM's
I can't seem to find motor caps that meet the voltage spec of 660V. 8uF
doesn't seem like a problem, but the combination together isn't looking
good. Are there any specific vendors I should be looking at? My usual
suspect of DigiKey isn't looking good. PDP-1. They do fail (thankfully, not often) - and
they are not
super-critical
as to value. If the one you're replacing has
the same marked value, you
should
be fine.
Yes, that's right. Find something with the same marked capacitance value.
The rated voltage can be the same or higher.
Thanks!
Kyle
9 Sep
9 Sep
7:24 a.m.
On Sun, Sep 8, 2019 at 11:18 PM Mattis Lind <mattislind at gmail.com> wrote:
Mouser has CDE 8 uF 660 VAC. 11 are on order from the
manufacturer.
https://www.mouser.se/ProductDetail/Cornell-Dubilier-CDE/SFA66T8K475B-F?qs=…
I have replaced several of these capacitors in PDP-8, LA30, PDP-9.
Thanks! Someone else pointed me to Mouser as well. Was hoping to find
something in stock, but I guess I can wait and go with Mouser; after all,
the PDP-8/I has been waiting well over 30 years for a new capacitor!
Kyle
1:02 p.m.
Amazon is your friend:
https://www.amazon.com/Capacitor-Motor-Quick-Connect-Snap/dp/B00HRNKI9Q/ref…
$13 bucks. Cheep.
Marc Howard
On Sun, Sep 8, 2019 at 7:41 PM Kyle Owen via cctalk <cctalk at classiccmp.org>
wrote:
On Sun, Sep 8, 2019, 20:39 Guy Dunphy via cctalk
<cctalk at classiccmp.org>
wrote:
>We recently replaced the ferroresonant capacitor in a power supply on the
CHM's
I can't seem to find motor caps that meet the voltage spec of 660V. 8uF
doesn't seem like a problem, but the combination together isn't looking
good. Are there any specific vendors I should be looking at? My usual
suspect of DigiKey isn't looking good.
Thanks!
Kyle
PDP-1. They do fail (thankfully, not often) - and
they are not
super-critical
as to value. If the one you're replacing has
the same marked value, you
should
be fine.
Yes, that's right. Find something with the same marked capacitance value.
The rated voltage can be the same or higher.
2:06 p.m.
BTW, Genteq is a reputable brand. It is the former GE capacitor division,
hence the name Gen(eral Electric)teq(technology).
On Mon, Sep 9, 2019 at 1:02 PM Marc Howard <cramcram at gmail.com> wrote:
Amazon is your friend:
https://www.amazon.com/Capacitor-Motor-Quick-Connect-Snap/dp/B00HRNKI9Q/ref…
$13 bucks. Cheep.
Marc Howard
On Sun, Sep 8, 2019 at 7:41 PM Kyle Owen via cctalk <cctalk at classiccmp.org>
wrote:
On Sun, Sep 8, 2019, 20:39 Guy Dunphy via cctalk
<cctalk at classiccmp.org>
wrote:
>We recently replaced the ferroresonant capacitor in a power supply on the
CHM's
value.
PDP-1. They do fail (thankfully, not often) - and
they are not
super-critical
as to value. If the one you're replacing has
the same marked value, you
should
be fine.
Yes, that's right. Find something with the same marked capacitance The rated voltage can be the same or higher.
I can't seem to find motor caps that meet the voltage spec of 660V. 8uF
doesn't seem like a problem, but the combination together isn't looking
good. Are there any specific vendors I should be looking at? My usual
suspect of DigiKey isn't looking good.
Thanks!
Kyle
3:55 p.m.
On Mon, Sep 9, 2019 at 4:06 PM Marc Howard <cramcram at gmail.com> wrote:
BTW, Genteq is a reputable brand. It is the former GE
capacitor division,
hence the name Gen(eral Electric)teq(technology).
On Mon, Sep 9, 2019 at 1:02 PM Marc Howard <cramcram at gmail.com> wrote:
Awesome! That's much cheaper than I was expecting. I'll make an
update when
I get it installed. It is physically much smaller than the previous one, so
I'll have to come up with another mounting solution. Maybe I'll find some
material to wedge underneath the cap to make it around the same height,
assuming the width is the same; should be able to use the same mounting
brackets that way.
Kyle
Amazon is your friend:
https://www.amazon.com/Capacitor-Motor-Quick-Connect-Snap/dp/B00HRNKI9Q/ref…
$13 bucks. Cheep.
8:05 p.m.
I don't know your location, but the surplus electronics/electricals
vendors here in the US tend to have lots of the the older oil caps (no
PCBs).
e.g.
https://www.electronicsurplus.com/capacitors/oil-filled-capacitor/page/2
10 Sep
10 Sep
6:49 a.m.
On Monday (09/09/2019 at 05:55PM -0500), Kyle Owen via cctalk wrote:
On Mon, Sep 9, 2019 at 4:06 PM Marc Howard
<cramcram at gmail.com> wrote:
If you were looking for a taller one than some have found, perhaps this
style fits better,
https://www.alliedelec.com/product/genteq/27l6016/70103256/
--
Chris Elmquist
BTW, Genteq is a reputable brand. It is the
former GE capacitor division,
hence the name Gen(eral Electric)teq(technology).
On Mon, Sep 9, 2019 at 1:02 PM Marc Howard <cramcram at gmail.com> wrote:
Awesome! That's much cheaper than I was expecting. I'll make an
update when
I get it installed. It is physically much smaller than the previous one, so
I'll have to come up with another mounting solution. Maybe I'll find some
material to wedge underneath the cap to make it around the same height,
assuming the width is the same; should be able to use the same mounting
brackets that way. Amazon is your friend:
https://www.amazon.com/Capacitor-Motor-Quick-Connect-Snap/dp/B00HRNKI9Q/ref…
$13 bucks. Cheep.
1702
days inactive
1704
days old
13 comments
8 participants
participants (8)
-
bfranchuk＠jetnet.ab.ca -
cclist＠sydex.com -
chrise＠pobox.com -
cramcram＠gmail.com -
guykd＠optusnet.com.au -
kylevowen＠gmail.com -
lbickley＠bickleywest.com -
mattislind＠gmail.com