Hotchip ODT-4000HD bad caps in PSU

[japlytic]

Yesterday, I received a Hotchip ODT-4000HD (readged Zinwell ZDT-420HD) made in Taiwan, from an eBay seller for $35 (including postage). The fault was not as serious as I thought .

All of the capacitors on the +5V rail have bulged. Replacing all of the capacitors fixed the problem completely. EC5, EC11 and EC22 (Jackcon) on the logic board from DC/DC converters were replaced as a good measure.

The power supply is made by Fairway Electronic Co. Ltd. , model VA3100-2.

Does anyone know about the CTC and TK brand capacitors?

Also, does anyone else have stories about digital terrestrial set-top boxs with bad capacitors? The digital tuner mandate happens in the US in 36 days and counting...

[dahogg]

Re: Hotchip ODT-4000HD bad caps in PSU

Found C15, C16, C19 and C12 all bulging. Replaced them. Still no go.
Replaced ALL electrolytics in the power supply.
Found useful circuit diagram on the web which suggested replacing EC5, EC11 and EC22 on the main board. Didn't do this as they checked out OK on ESR.
Finally found the problem caused by these bad capacitors. ALL three overvoltage protection zeners, ZD1, ZD2 and ZD3 were short circuit. The circuit diagram doesn't say what these are and they're too small to read. Replaced ZD1 with 5.6v, ZD2 with 13v and ZD3 with 27v zeners. (tried lower values but they fire the protection SCR).
BINGO. All working.
Many thanks for previous posts.

[Vonnie]

Re: Hotchip ODT-4000HD bad caps in PSU

Yesterday, I received a Hotchip ODT-4000HD (readged Zinwell ZDT-420HD) made in Taiwan, from an eBay seller for $35 (including postage). The fault was not as serious as I thought .

All of the capacitors on the +5V rail have bulged. Replacing all of the capacitors fixed the problem completely. EC5, EC11 and EC22 (Jackcon) on the logic board from DC/DC converters were replaced as a good measure.

The power supply is made by Fairway Electronic Co. Ltd. , model VA3100-2.

Does anyone know about the CTC and TK brand capacitors?

Also, does anyone else have stories about digital terrestrial set-top boxs with bad capacitors? The digital tuner mandate happens in the US in 36 days and counting...

Hi I also have a VA3100-3 PSU and found that it generates a soft slow clicking noise, with no output whatsoever. It appears as if the power Mosfet (2SK2645) is not doing its thing. I have taken out the Fet and tested it (as best I can) and am not sure whether it is faulty. The driver IC (KA3842A) could also be faulty. But, after reading your comments I wonder if it isn't only the caps that are causing it to malfunction and failing it to start up?

[gonzo0815]

Re: Hotchip ODT-4000HD bad caps in PSU

Bad caps can cause this problems easily.
You would avoid much trouble, if you replace any crap cap before going further in troubleshooting.
Those zener diodes are usually the over voltage protecting circuit, as they get shorted, if there is a longer over voltage present.
This would trip the OCP circuit and avoid damaging the load.
So you have to check them always if bad caps are in the circuit.

Sutch small SMPS are widely used in Sat boxes, dvd players, digital terrestrial boxes and any similar device.
I have had a few of them fixed, but the last Denon DVD Divx player had a shorted DSP board too.

[starfury1]

Re: Hotchip ODT-4000HD bad caps in PSU

That psu almost looks like the old grey playstation one (different I know )
but similar probs etc with zeners.

If you look up the liberty 620w post Japlytic you find web address of the manufacturers of those CTC's
(think its them from what was worked out, posted)
post, page

https://www.badcaps.net/forum/showth...7&page=2&pp=20


http://www.0759.com/CECWEB/index.aspx?lang=en


seems Enermax builds are using them
(looking to be another great crap cap)

BTW if you did write it down.
what was the chip number on that 8 pin Dil IC ?
Just wondering...thks

HTH cheers

[ogarek123]

Re: Hotchip ODT-4000HD bad caps in PSU

Hi
The little 8pin IC on the PC Board is: UC3842B
I hope that helps. I'm about to replace all of the caps, and the Zenners.
I do hope that will fix my problem

Thanks

[ogarek123]

Re: Hotchip ODT-4000HD bad caps in PSU

I have the same problem as Vonnie. There is a slow clicking noise coming from the power supply.
I did change the caps and the three zenner diodes, as it seamed the easiest to do, but it did nothing to fix the problem. I found a replacement for the IC and changed it to UC3842BNG, but with no success.

Question to Vonnie:
Did you by any chance get to fix your PSU?
I'm afraid that shortly I would have changed everything on that board.

Many Thanks

[Vonnie]

Re: Hotchip ODT-4000HD bad caps in PSU

Thanks for your advise. I did change most of the electrolutics (5 as far as I can remember) until it started working! 3 of them showed signs of leakage. So I guess they just dried up or something. You saved me a lot of unneccesary troubleshooting time. I guess at the end of the day it doesn't cost too much too change all the electrolutics first - especially on switchmodes.

[severach]

Re: Hotchip ODT-4000HD bad caps in PSU

That clicking is easy to find when scorched earth electrolytic replacement doesn't work. Put a plastic straw in your ear and run it around the board.

[father_fixit]

Re: Hotchip ODT-4000HD bad caps in PSU

Does anyone know about the CTC and TK brand capacitors?

I have a Western Digital External HDD that kept faulting. It is powered by a REXON AC-005 power brick that supplies 5vdc and 12vdc. I think it was the 5 volt line (can't remember) that would be ok if no HDD was attached to the enclosure. It dipped way down when a HDD was plugged in. I cracked open the PS and found two bulging, slightly leaking CTC 1000uF 16v capacitors. I swapped them with some from a dead desktop psu and it works fine now even though they were junk Jamicons. I am going to order some good ones to recap the whole thing along with several other needy mobos and psu's.

[japlytic]

Re: Hotchip ODT-4000HD bad caps in PSU

The Toshiba HD-S23 and a Sharp box were also rebadges of the ZDT-420HD as well. In this month's edition of Silicon Chip (Serviceman's Log), there was mention that the repairers were told that they were non-repairable devices (no support, no circuits, no spare parts ) and if under warranty - replacement, otherwise, it becomes landfill (for something that actually can be fixed!)

Actually, the power supply boards can be replaced in many boxes or at least be repairable (I replace all electrolytics with Chemi-Con KY units, with the 400/450V unit being a Chemi-Con KMG or snap-in KMH if the mounting holes and board space permit it)

Also mentioned in that issue of Silicon Chip was a Toshiba HD-S23 (Zinwell ZDT-410HD) with an insensitive remote control sensor (range was down to one metre, even with good batteries) caused by noise due to faulty bypass capacitors near the IR sensor.

When are manufacturers going to wake up and install quality as standard in the electrolytics department???

[PCBONEZ]

Re: Hotchip ODT-4000HD bad caps in PSU

CTC is a Taiwan brand and known leakers.
http://babelfish.altavista.com/babel...abcde.html#ctc

TK is a Japanese brand since 1950 - Toshin Kogyo CO., LTD
http://www.toshincon.com/toshin-e/INDEX.html

.