I have a 6W ceiling light with 30x 2835 LEDs in series, the driver is
externally mounted and is on the blink (flashed for a while, now mainly
nothing, occasional flicker) no bulgy looking capacitors, PCB seems to
be a reference design for a bright power BP3133A chip.

So I need a replacement CC driver that will provide 60mA @ 90V, but I
don't seem to be finding such a thing, anyone?

On Saturday, 21 April 2018 16:28:44 UTC+1, Andy Burns wrote:
I have a 6W ceiling light with 30x 2835 LEDs in series, the driver is
externally mounted and is on the blink (flashed for a while, now mainly
nothing, occasional flicker) no bulgy looking capacitors, PCB seems to
be a reference design for a bright power BP3133A chip.

So I need a replacement CC driver that will provide 60mA @ 90V, but I
don't seem to be finding such a thing, anyone?

Fairly trivial to make a CR ballast.


NT

wrote:

Fairly trivial to make a CR ballast.

would that be non-isolated from mains? if so I wouldn't fancy it for the
lamp part itself ...

On Saturday, 21 April 2018 18:12:09 UTC+1, Andy Burns wrote:
tabbypurr wrote:

Fairly trivial to make a CR ballast.

would that be non-isolated from mains? if so I wouldn't fancy it for the
lamp part itself ...

yes they're not isolated. I take it your LEDs are touchable then.


NT

wrote:

Andy Burns wrote:

tabbypurr wrote:

Fairly trivial to make a CR ballast.

would that be non-isolated from mains?

yes they're not isolated. I take it your LEDs are touchable then.

not touchable, but the LED strip (unusually all in series) is only
separated from the aluminium case by a strip of some tape, the LED part
is 3m distant from the driver, with just two single insulated cables for
+ and - to it, no earth available ...

The other thought is to replace the LED strip with more conventional 12V
LED strip that's cuttable every nth-LED and use a more easily obtainable
driver.

On Saturday, 21 April 2018 18:44:04 UTC+1, Andy Burns wrote:
tabbypurr wrote:
Andy Burns wrote:
tabbypurr wrote:

Fairly trivial to make a CR ballast.

would that be non-isolated from mains?

yes they're not isolated. I take it your LEDs are touchable then.

not touchable, but the LED strip (unusually all in series) is only
separated from the aluminium case by a strip of some tape, the LED part
is 3m distant from the driver, with just two single insulated cables for
+ and - to it, no earth available ...

The other thought is to replace the LED strip with more conventional 12V
LED strip that's cuttable every nth-LED and use a more easily obtainable
driver.

You can make isolated CR PSUs by starting with 2 mains transformers back to back. But really if it runs on 90v it should use earth & proper insulation.


NT

wrote:

You can make isolated CR PSUs by starting with 2 mains transformers
back to back. But really if it runs on 90v it should use earth &
proper insulation.
I hadn't appreciated what voltage it must have been running at until it
died and I dismantled it (30 white LEDs in series at ~3V each) no
markings on the PSU, but I notice the output smoothing cap is only 50V
rated, so probably explains why it only lasted a couple of years.

On 21/04/18 18:04, wrote:
On Saturday, 21 April 2018 16:28:44 UTC+1, Andy Burns wrote:
I have a 6W ceiling light with 30x 2835 LEDs in series, the driver is
externally mounted and is on the blink (flashed for a while, now mainly
nothing, occasional flicker) no bulgy looking capacitors, PCB seems to
be a reference design for a bright power BP3133A chip.

So I need a replacement CC driver that will provide 60mA @ 90V, but I
don't seem to be finding such a thing, anyone?

Fairly trivial to make a CR ballast.

C plus a FW bridge is all thats really needed.

NT



--
"What do you think about Gay Marriage?"
"I don't."
"Don't what?"
"Think about Gay Marriage."

On Saturday, 21 April 2018 19:10:07 UTC+1, The Natural Philosopher wrote:
On 21/04/18 18:04, tabbypurr wrote:
On Saturday, 21 April 2018 16:28:44 UTC+1, Andy Burns wrote:

I have a 6W ceiling light with 30x 2835 LEDs in series, the driver is
externally mounted and is on the blink (flashed for a while, now mainly
nothing, occasional flicker) no bulgy looking capacitors, PCB seems to
be a reference design for a bright power BP3133A chip.

So I need a replacement CC driver that will provide 60mA @ 90V, but I
don't seem to be finding such a thing, anyone?

Fairly trivial to make a CR ballast.

C plus a FW bridge is all thats really needed.

NT

If your name isn't bodgit & scarper you need a series R to limit inrush current to a value the LEDs will survive, and to act as a fuse when/if the C shorts. You'll also want a discharge R across the C.


NT

In article ,
Andy Burns writes:
wrote:

You can make isolated CR PSUs by starting with 2 mains transformers
back to back. But really if it runs on 90v it should use earth &
proper insulation.
I hadn't appreciated what voltage it must have been running at until it
died and I dismantled it (30 white LEDs in series at ~3V each) no
markings on the PSU, but I notice the output smoothing cap is only 50V
rated, so probably explains why it only lasted a couple of years.

What makes you think the LEDs are a single series chain?
Often there are two or more series chains on the tape,
connected in parallel, so the driving voltage is lower
(or variations such as adjacent LEDs paired in parallel).

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

Andrew Gabriel wrote:

What makes you think the LEDs are a single series chain?

Well ... I thought I'd looked closely enough to see it zig-zag as a
single run (this tape has no cut marks or resistors) but looking more
closely they are in series runs of 5 LEDs, with 6 groups in parallel.

Often there are two or more series chains on the tape,
connected in parallel, so the driving voltage is lower
(or variations such as adjacent LEDs paired in parallel).

Yes, even still constant 60mA @ 15V drivers seem rare ...

Andy Burns wrote:

even still constant 60mA @ 15V drivers seem rare ...

Oh silly, of course now I'm looking for 300mA and there seem to be
plenty of those ...

In article ,
Andrew Gabriel wrote:
In article ,
Andy Burns writes:
wrote:

You can make isolated CR PSUs by starting with 2 mains transformers
back to back. But really if it runs on 90v it should use earth &
proper insulation.
I hadn't appreciated what voltage it must have been running at until it
died and I dismantled it (30 white LEDs in series at ~3V each) no
markings on the PSU, but I notice the output smoothing cap is only 50V
rated, so probably explains why it only lasted a couple of years.

What makes you think the LEDs are a single series chain?
Often there are two or more series chains on the tape,
connected in parallel, so the driving voltage is lower
(or variations such as adjacent LEDs paired in parallel).

I had a GU10 LED explode. It was definitely series wired.

--
from KT24 in Surrey, England
"I'd rather die of exhaustion than die of boredom" Thomas Carlyle

Andrew Gabriel wrote:

What makes you think the LEDs are a single series chain?

Apart from the zig-zag track, the other thing that fooled me, was that
unlike other tapes which have + and - connections at both ends, this one
has + at one end, and - at the other ...

I was just thinking the same. 90 v that is a little odd. Are we sure the
leds all still work and that a short somewhere in this sticky insulator is
not what has done for the psu in the firs place?
Lossless droppers using capacitors are generally only used in cases where
you cannot actually touch the cable at all, I used to have one in a pifco
torch that was rechargeable, eventually the capacitor went leaky and filled
the room with orrible smelling smoke.
Yuck.
Brian

--
----- -
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please!
wrote in message
...
On Saturday, 21 April 2018 18:44:04 UTC+1, Andy Burns wrote:
tabbypurr wrote:
Andy Burns wrote:
tabbypurr wrote:

Fairly trivial to make a CR ballast.

would that be non-isolated from mains?

yes they're not isolated. I take it your LEDs are touchable then.

not touchable, but the LED strip (unusually all in series) is only
separated from the aluminium case by a strip of some tape, the LED part
is 3m distant from the driver, with just two single insulated cables for
+ and - to it, no earth available ...

The other thought is to replace the LED strip with more conventional 12V
LED strip that's cuttable every nth-LED and use a more easily obtainable
driver.

You can make isolated CR PSUs by starting with 2 mains transformers back
to back. But really if it runs on 90v it should use earth & proper
insulation.


NT

Brian Gaff wrote:

Are we sure the leds all still work

yes, the LEDs give the occasional flash and flicker
Lossless droppers using capacitors are generally only used in cases where
you cannot actually touch the cable at all

It's one of your favourite SMPSUs, and I've ordered a replacement 300mA
12 to 24V constant current one for it, the 90V was a red herring.

On Saturday, 21 April 2018 21:05:06 UTC+1, Andy Burns wrote:
Brian Gaff wrote:

Are we sure the leds all still work

yes, the LEDs give the occasional flash and flicker
Lossless droppers using capacitors are generally only used in cases where
you cannot actually touch the cable at all

It's one of your favourite SMPSUs, and I've ordered a replacement 300mA
12 to 24V constant current one for it, the 90V was a red herring.

If the herring had 90v across it I'm pretty sure it's a dead herring now


NT

On Sat, 21 Apr 2018 16:10:06 -0700, tabbypurr wrote:

On Saturday, 21 April 2018 21:05:06 UTC+1, Andy Burns wrote:
Brian Gaff wrote:

Are we sure the leds all still work

yes, the LEDs give the occasional flash and flicker
Lossless droppers using capacitors are generally only used in cases
where you cannot actually touch the cable at all

It's one of your favourite SMPSUs, and I've ordered a replacement 300mA
12 to 24V constant current one for it, the 90V was a red herring.

If the herring had 90v across it I'm pretty sure it's a dead herring now

Whereas a Torpedo fish would simply have claimed it was recharging its
batteries. :-)

--
Johnny B Good