Re: Help, SMPS Question
Hi.
I replaced C1-C8 (original caps Jamicon 85deg with
Chong 105deg 50v. Not sure if any of these are low-esr.
rievax_60: will recheck points you mentioned later.
Thanks.
Alembic
Member
Last Activity: 10-17-2015, 06:07 AM
Joined: 03-13-2010
Location: Scotland
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Re: Help, SMPS Question
Hi All.
Using a standard brushless 12v/0.12amp as a load
(not ideal I know) I register the following readings:
On load +ve output of between 19v - 22v
Off load -ve output of around 35v
On load -ve output of between 19v - 22v
Off load +ve output of around 33.9v
These readings rise and fall between those points.
I rigged a LED across the outputs to get
some kind of visual feedback and it`s pulsating.
Some components get a little warm but nowhere
near as...Leave a comment:
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Re: Help, SMPS Question
Hi.
Point taken. What would be a good dummv load
to test this type of supply?
Thank you.Leave a comment:
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Re: Help, SMPS Question
Hi.
In reply.
R2 should have been fubar: R2 reading ok =22 ohm.
FET was ok. However made a standard re-check of FET
i.e. G,D,S check, appears to be ok.
What are the Wattage: One is 55w the other is 21w (It`s what I had
available to hand)
What are the cold resistance of these two lamps? approx. 0.4
Thanks.Leave a comment:
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Re: Help, SMPS Question
Hello everyone.
Responded to your suggestions re
components to check.
As it stands, I replaced the UC3842N as I felt
it could be defective.
I then decided to attach a dummy
load of two 12v auto bulbs to the secondary
+and- outputs and powered up.
The bulbs are pulsating and light dimmly this
is also accompanied by a light ticking sound (approx
5 ticks a second) Re-checked board for open/dry joints
but seems ok.
R13 and D6 do get warm but nowhere near as warm as...Leave a comment:
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Re: Help, SMPS Question
what about D5, C20 and R15? D5,R15 reading ok.
What is the exact model of this SOUNDCRAFT? E8 series mixer.
Thanks
Incidentally I came across the following text file.
Seems I`m not alone.
===============
When I saw the first couple of these mixers with catastrophic PSU failure, I thought of them as random events. Now I've seen at least half a dozen I'm beginning to think there's a design flaw. The PSU is a bog ordinary switchmode, and the failures are all the same - high ESR caps around the 3842...Leave a comment:
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Re: Help, SMPS Question
What components did you replace? R13,D4 D7 D6 Fet1,ic1
R13 Value read was ok but replaced anyway due to visible
appearance it does get WARM.
Line voltage: 240AC 50Hz
Proper Multimeter settings used re: AC/DC
eccerOr: D2 ok but I replaced it with same component make.
Will replace C1,C8 - unable to check capacitors properly as
I do not have cap tester.
D6 gets hot very quickly. i.e. in the time it takes me to
take a few quick measurements and then, if left
long enough,becomes u/s....Leave a comment:
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Re: Help, SMPS Question
Sure thing. just added them. should be
there by now.Leave a comment:
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Help, SMPS Question
Hi everyone
I am attempting to repair a PSU from a
Soundcraft eSeries mixer.
The issue is this: It appears to have gone
massively overvoltage. According to the schematic
the voltage across the reservoir cap should be 170Vdc
I am reading just over double that. Visual inspection
of the board clearly shows excessive heat around some
resistors. I replaced a few suspect components and
managed to achieve +and- 15v on the output but
that didn't last for long. Back to square 1.. struggling.
Q: What part of the design... -
Re: Mirage Electronics AD-1700 REV:F Problem
Hi PlainBill
Series used: EXR 105°C - vent 9L10.
[I]Using an external power supply for the inverter isolates the
logic card and display from this noise:[/I]
The external supply
is purely powering the CCFL`s. The original Power/Invertor
board is powering the Logic/main board.(with the exception
that the CCFL`s are disconnected.)
Interesting point about supply noise though. As I pointed out,
in the original post, of there being a slight interference along...Leave a comment:
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Re: Mirage Electronics AD-1700 REV:F Problem
Hi
Only on the power supply / inverter, I figured the fact the display
is steady and stays on firing the BLights from an outside source
would rule out any issue with the logic board.
The only cap I did`nt change was the 100uf 400v.
I checked the Voltage across that cap in "fault mode" and it
is steady at (if memory serves) 339Vdc.
Replacements used: Hitano 105deg
Thanks for reply.
Alembic.Leave a comment:
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Mirage Electronics AD-1700 REV:F Problem
Hi Everyone
Hope someone can help.
Troubleshooting the AD-1700 Mirage board
at the moment.
The fault is as follows: Screen fires up for approx
3-4 mins - although this period can be shorter- then
cuts out and can flash on randomly.
When screen is on there is also a slight vertical jitter and
a hint of interference.
I suspect some kind of thermal issue but not too
sure.
Changed all the caps,changed the 12v Reg as I felt it
was getting pretty hot.
Disconnected the BLights and powered them from another...
No activity results to display
Leave a comment: