Re: HP CP1025 faded mirror
yes. flat mirror
it placed 45^ angled in the laser assembly. after acrylic lens...
pavithra_uk
Member
Last Activity: 09-12-2024, 03:18 AM
Joined: 11-09-2010
Location: SRI LANKA
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HP CP1025 faded mirror
This is what happened to 45 degree angled mirror of laser assembly. mirror surface coating is almost completely etched away.
what can be the possible solution for this?
Printer - HP colour laserjet CP1025
Symptoms - faded printouts... -
Re: Surge protection
For small power adapters or other equipment without ground connection, I use 1 varistor (470V usually) after fuse.
L ---- FUSE ----+-- To adapter
MOV
N --------------+---To adapter
if adapter have no ground connection, but it has wires long enough or connected with other ground, arcing can occur between AC input and DC low voltage rails. in this case, you must add 2 varistors and ground them.
for power adapters like you mentioned, 3 varistors to protect LN, LE, NE and make PSU case grounded properly...Last edited by pavithra_uk; 09-07-2022, 10:51 AM.Leave a comment:
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Re: Checking an oscillating fan motor
if cap failed, you can turn the motor by manual start.
in this case, I think either power is not getting to motor or internally disconnected winding.
first check if power is getting into motor.
there is a thermal fuse in some motors. it is placed touched with winding. if it failed (this usually happen if motor stall for long time)Leave a comment:
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Re: Hello, do you know what is this component pls of Nikon D800 camera shutter?
Chip can be FMG11A Dual N transistors
if so, capacitor may be 0.1uf - 1ufLeave a comment:
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CRT Oscilloscope repair
I received two GW Insteak GOS-622G 20Mhz Analog CRT oscilloscopes to repair. both have shorted transistors and fried resistors in Y plate drive circuit.
since both have same issue, I want to find if this common issue with this scope or any other cause. here I attached schematic of Y output circuit.
C2570 Transistor. this is Gigahertz range low power transistor (VCBO-25V, VCEO-12V, 50mA) for use in VHF/UHF range. but, that transistor here in the circuit of 160V supply. both scopes have both this transistor fried.
Transistors with heatsink - 2SB648A,... -
Re: SB190 rectifier diode alternative
I found several LED backlit monitors with LED supply voltage less than 20V but using 200V schottkey diodes in power supply rail. and they failed after some time. this can be the cause. but don't know why they use high voltage diodes....Leave a comment:
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Re: SB190 rectifier diode alternative
SB1100 is perfectly fine.
it is same diode as SB190 with higher voltageLeave a comment:
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Re: APC ES 400 UPS boardview needed
May be I can get photos of ES500 UPS. seems ES 350, 400, 500 have same boardLeave a comment:
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TNY27x thermal shutdown issues
Few years ago I found a PSU (Delta, 500W) that works fine few minutes and then turn off itself. later I found that standby 5V (and ~12V to controller) ic TNY279 overheats and then shut down. replaced with new one and problem solved.
and I found few other PSUs with same problem. two mobile USB power packs too. all these had TNY278, 279
Anyone here had similar experience ?
How these chips fail such a way? looks like internal mosfet on resistance increase or current sense element failure.. -
Lubricating plastic wheels in geared motors
What can be used for lubricating plastic wheels in small geared motors ?
General purpose automotive grease
Motor engine oil
Motor Gear oil
Silicone lubricating spray
Rubber grease (used to lubricate orings in break calipers)... -
Re: J107 Tantalum cap burning inside a USB hub?
I once saw macbook air with burnt tant (cpu vcore) anyway not pcb or nearby parts burned...Leave a comment:
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Re: recap help AcBel PSU
This PSU is for my use. so I can periodically check status of capacitors....Leave a comment:
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Re: recap help AcBel PSU
12V rail have only 1 cap (1200uF 16V)
All others including 5Vsb have 2 caps with series inductor.
Stock caps are Ltec LYZ 8x20mm 1000uF 10V ESR rated for 0.040-Ohms
1200uF 16V 10x23mm ESR 0.021-Ohms
Teapo SC 3300uF 16V 10x35mm ESR rated for 0.026-ohms...Last edited by pavithra_uk; 06-29-2021, 07:04 AM.Leave a comment:
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Re: testing voltage of unknown SMD caps
examine pcb before cap desolder. we can get idea of how much voltage on these caps. for example, caps connected with 12V line, at least rated for 16V.
voltage test I think useless. ceramic caps have no sharp voltage margin like tantalum.
I've tested processor vrm output smd ceramic caps (1205, 10uF, vcore of less than 1.5v) with 24V. nothing happenedLeave a comment:
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Re: recap help AcBel PSU
Thanks for the information.
So.. Teapos are the solution. they are relatively newer, have 0.03 ESR came with PSU.
what you think about capacity? stock 12V rail was 1, 1200uF 16V. I can put 1500,2200 or even 3300 there....Leave a comment:
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Re: recap help AcBel PSU
Why higher ESR ? any reason for using high ESR caps for smps?
I tested those caps for ESR randomly. with component tester
KZG 3300uF have 0.01Ohms...Leave a comment:
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recap help AcBel PSU
I found used PSU AcBel PC6001 ~250W from IBM thinkcenter Core2Duo system. Almost every output rail caps were bulged except 12V rail single cap. caps were Ltec
12V - 1200uF 16V
5V - 1000uF 10V before coil 1000uF 10V after coil
3.3V - 1000uF 10V before coil 1000uF 10V after coil
5Vsb - 1000uF 10V before coil, 470uF 16V after coil
Since I have no access to buying new branded caps, I'm going to replace caps with used caps I pulled from dead PSUs and Motherboards.
I need cap experts ideas about it.
This PSU will... -
Re: Motherboard repair manual electronic
Are motherboard manufacturers published their board repair manuals ?????Leave a comment:
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Re: Dell 2408WFP Vertical Lines
may be Column drive flex cable has bad connection with panel glass (this is stick with glass & conductive lines)
Check that area flex cable with pressed with finger as soon as cold start display (have to dissasemble panel from base)
it problem gone.., try to glue that area might helpLeave a comment:
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