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Leopard replied to Mitsubishi Melservo MR-J2S-100A alarm: AL.E9

in Troubleshooting Power Supplies and Power Supply Design

11-27-2018, 10:57 PM
Re: Mitsubishi Melservo MR-J2S-100A alarm: AL.E9

Thanks for the response. Nice to hear that the failure mode has been consistent.

We've luckily had spare units for the ones that have been acting up, but apparently this model is outdated and hard to get nowadays.

I'll order some optocouplers and will see if these can be brought back to life. ...

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Leopard replied to Mitsubishi Melservo MR-J2S-100A alarm: AL.E9

in Troubleshooting Power Supplies and Power Supply Design

11-26-2018, 11:21 PM
Re: Mitsubishi Melservo MR-J2S-100A alarm: AL.E9

Hi Per,

Sorry about the thread necro, but anyway:

We are slowly starting to get failures of these Melservo units at work.

What were the initial error codes & symptoms?

We have two units which show AL.33 (overvoltage) and two units which had a hard time getting to a working state, initially showing AL.16 or AL.E9. Once they warmed up, they would work normally, but this took longer and longer as months passed.

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Leopard replied to Viewsonic VX724 troubleshooting

in Troubleshooting Computer Displays

08-18-2012, 07:35 AM
Re: Viewsonic VX724 troubleshooting

I decided to test the BYV32-150 in place of the Schottky. The monitor fired up and it works like new now. I'll get the (proper) replacement next week but I wanted to test it to narrow down any other possible faults.

9 caps and one rectifier later, success. Parts cost around 12€.

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Leopard replied to Viewsonic VX724 troubleshooting

in Troubleshooting Computer Displays

08-17-2012, 01:20 AM
Re: Viewsonic VX724 troubleshooting

I went to my local electronics store this morning. They had a BYV32-150 in stock. It is a dual rectifier with the same TO-220 case and also a positive centertap like the MBR10100CT. It is rated for 18A and 150V.

Can I use that as a replacement? Or does it absolutely have to be a Schottky rectifier?

[url=http://www.datasheetcatalog.org/datasheet/diodes/ds30028.pdf]MBR10100CT pdf[/url]
[url=http://www.datasheetcatalog.org/datasheet/GeneralSemiconductor/mXuuutr.pdf]BYV32-150 pdf[/url]Re: Viewsonic VX724 troubleshooting

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Last edited by Leopard; 08-17-2012, 01:59 AM. Reason: added pdf links
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Leopard replied to Viewsonic VX724 troubleshooting

in Troubleshooting Computer Displays

08-16-2012, 11:14 AM
Re: Viewsonic VX724 troubleshooting

Removed the Schottky dual diode, both of the diodes are ka-pooff (other measures open in both directions, I cannot get a measurement from the other which indicates that it is probably shorted). The short was removed from the +12V rail. Also the base of the Schottky (where it was soldered) measures no short now - this probably indicates that the transformer is working! I'll get a replacement next week, but I have a good feeling in my gut at the moment - this will probably get the monitor up and running.

About the caps that I used,...

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Leopard replied to Viewsonic VX724 troubleshooting

in Troubleshooting Computer Displays

08-16-2012, 07:13 AM
Re: Viewsonic VX724 troubleshooting

Back with pictures of the overall areas.

If you need pics of specific spots please tell.

I am getting stable voltage at the mains cap (around 330V which sounds correct since we have 230VAC here in Finland)

I was thinking - what would cause the Schottky to fail? Heat, high ripple current from the primary side since the mains cap was a goner?

And (in circuit - havent desoldered it yet) the Schottky measures open in all directions (from both anodes to cathode and from cathode to anodes) - that...

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Last edited by Leopard; 08-16-2012, 07:29 AM. Reason: more info
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Leopard started a topic Viewsonic VX724 troubleshooting

in Troubleshooting Computer Displays

08-16-2012, 03:34 AM
Viewsonic VX724 troubleshooting

Hey all,

I have a VX724 monitor which is giving me a headache. I've replaced all electrolytic caps on the power supply / inverter board (including the mains cap which had leaked and the positive lead had corroded off - good job CapXon) and 3 caps on the logic board with fresh Panasonic FR/FM/FC series caps.

Symptoms are pretty straightforward, it will not turn on (no power light) and the power supply is ticking - it is trying to start but there is a short somewhere. One day it just silently went out and didnt have any signs of life.

The caps in the Royer...

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Leopard replied to P4SD - case LEN

in Troubleshooting Desktop Motherboards, Graphics Cards, and PC Peripherals

05-28-2010, 09:45 AM
Re: P4SD - case LEN

I cannot see any pictures in the first post. They would help a lot in this case.

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Leopard replied to Help identifying caps on this video card

in Troubleshooting Desktop Motherboards, Graphics Cards, and PC Peripherals

05-11-2010, 03:47 AM
Re: Help identifying caps on this video card

Polys do not usually have vents - they were most probably Sacon FZ electrolytic caps. (Metal can without plastic sleeve, blue marker on top)

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Leopard replied to VX922 help...

in Troubleshooting Computer Displays

04-28-2010, 04:00 AM
Re: VX922 help...

Check the transformer solder joints, I fixed a VX922 which had bad caps (CapXon) and broken solder joints on the large transformer.

EDIT: Also the cap next to the "GP" logo should be replaced if it is one of the original caps.

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Leopard replied to Video adapters - bad caps

in Troubleshooting Desktop Motherboards, Graphics Cards, and PC Peripherals

04-04-2010, 05:40 PM
Re: Video adapters - bad caps

That is a common problem especially on Nvidia 8800 and 9800 series cards. This happens due to BGA joints going bad/cracking due to heat stress beneath the GPU. There is a certain "oven trick" which has worked for many owners of those cards. Google it, I think I found it on [H] forum a while back.

E: Depends on the card though, I had a Radeon 9250 card which displayed random garbage and suffered from video corruption and it was due to bad caps. (Licon)...

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Leopard replied to Intel D101ggc

in Troubleshooting Desktop Motherboards, Graphics Cards, and PC Peripherals

03-31-2010, 09:22 AM
Re: Intel D101ggc

Some boards have silkscreening done the opposite way (white stripe is actually +voltage instead of ground). Check the polarity with a multimeter.

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Leopard replied to Yamaha TA-20 guitar amplifier.

in Troubleshooting Audio Equipment

03-16-2010, 06:40 AM
Re: Yamaha TA-20 guitar amplifier.

It could be a bad solder joint, though an hour seems an awfully long time for solder-related problems to appear.

You could try replacing the resistor - odds are that its value has drifted from its' original value over the years anyway.

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Leopard replied to Antec Earthwatts 380W +5VSB failure, wont turn on

in Troubleshooting Power Supplies and Power Supply Design

03-13-2010, 07:04 AM
Re: Antec Earthwatts 380W +5VSB failure, wont turn on

The latter, 2 x 1000uF 16V and 2 x 1000uF 10V....

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Leopard replied to Antec Earthwatts 380W +5VSB failure, wont turn on

in Troubleshooting Power Supplies and Power Supply Design

03-13-2010, 06:02 AM
Re: Antec Earthwatts 380W +5VSB failure, wont turn on

Took some overall pictures - I can get better pics if needed.

Yeah I know the Nichicon is a bit old, but it tested good with an ESR meter.

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Leopard replied to Antec Earthwatts 380W +5VSB failure, wont turn on

in Troubleshooting Power Supplies and Power Supply Design

03-11-2010, 07:03 PM
Re: Antec Earthwatts 380W +5VSB failure, wont turn on

Yeah I tried to run the supply without a motherboard. (Wont turn on via jumpering green wire + ground, purple wire to ground is 1.2-1.8V mentioned earlier)

The PC this supply was in has already got a replacement supply (A Corsair unit) and it is working fine.

I'll return with pics later....

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Leopard started a topic Antec Earthwatts 380W +5VSB failure, wont turn on

in Troubleshooting Power Supplies and Power Supply Design

03-11-2010, 12:31 PM
Antec Earthwatts 380W +5VSB failure, wont turn on

Got a problem with one of these units.

The power supply is visually fine, no broken / damaged solder joints, no burnt components or bulged caps. Caps are OST throughout the unit, except for the mains cap which is a Nippon Chemi-con.

Symptoms are:
Low +5VSB, below 2V
The +5VSB voltage is very jumpy (changes rapidly from about 1.2V to 1.8V and also values inbetween)

I changed the 3300uF 10V cap for the +5VSB but this didn't change anything.

Any idea what could cause such symptoms if we rule out the caps and solder joints?...

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Leopard replied to Repairing a FSP250-60GTV (PF)

in Troubleshooting Power Supplies and Power Supply Design

11-24-2009, 12:16 PM
Re: Repairing a FSP250-60GTV (PF)

All right, I'm working on this again. Going to order replacement caps at the end of the week.

I have a "gutless wonder" power supply lying around. I was thinking if I could replace the Fortrons +12V schottky rectifier with the +5V schottky rectifier of the gutless supply. The part number is of the SB3040PT.

Datasheet

Fortron part SB1660 datasheet...

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Leopard started a topic ZyXEL P-660H-D1 recap

in Troubleshooting & Designing Networks

10-21-2009, 12:08 PM
ZyXEL P-660H-D1 recap

I will be doing a recap on my ADSL modem soon, since hosting Skype conversations and game matches has become nearly impossible due to lag issues and random drop-outs for me. Hopefully this is a capacitor issue and even if it's not, this will be a preventive recap.

The modem in question is a ZyXEL P-660H-D1. Maximum capacitor height in this unit is 18mm, but 20mm caps could be used without problems. Any higher than that will require drilling holes to the plastic cover.

See attached pic.

[SILKSCREEN MARKING] # [CAPACITOR BRAND / SERIES] # [CAPACITANCE...

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Leopard replied to HP F1503 Non-Functional

in Troubleshooting Computer Displays

10-19-2009, 11:10 AM
Re: HP F1503 Non-Functional

Caps are also be found in wall warts and they are just as likely to go bad inside them. Open the supply up and post pics.

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Viewsonic VX724 troubleshooting

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Antec Earthwatts 380W +5VSB failure, wont turn on

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ZyXEL P-660H-D1 recap

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