Samsung DTB-H260F HDTV Tuner

[bluto]

I have a Samsung DTB-H260F HDTV Tuner that is not working. When the power button is pressed the blue power light comes on for 1/4 of a second and then goes off. Cracked the case open and found one bulged Samxon 1000uf 10v cap on the power supply board. Replacements for all the electrolytic caps on the psu board are on the way from digikey. Will update on the status of the patient once they come in. See attached image for the problem cap.

[japlytic]

Re: Samsung DTB-H260F HDTV Tuner

If replacing this capacitor makes the set-top box work again, replace all of the capacitors on the secondary side of the power supply board with Nippon Chemi-Con KY Series.
Are we still losing faith in Samxon?

[Wizard]

Re: Samsung DTB-H260F HDTV Tuner

That poor samxon was overheated in that hot spot. Not the Samxon issue.

Cheers, Wizard

[Krankshaft]

Re: Samsung DTB-H260F HDTV Tuner

Nope it's not about heat that's Samxon GF series the series is pure crap they bulge regularly in hot LCD inverters. This is the Nichicon HM series of Samxon the one where they dropped the ball.

Just get a decent series from any of the top companies like Panasonic FCs for example and you'll be fine. Replace any other GFs you find too.

Better yet just replace all the secondary caps to start on a clean slate.

I see you already order from Digikey as long as the caps are low ESR then you'll be fine.

My Cablecard set top box PSU is full of Samxons too. I peep in through the vent holes regularly and see no hunter green Samxons (GF series) or bulging whatsoever so I'm exempt from the GF plague .

This is why I still don't trust Samxon to the same extent I trust Panasonic, UCC, and Nichicon. They in my opinion are still new kids on the block.

[Wizard]

Re: Samsung DTB-H260F HDTV Tuner

Samxon; I use GC and GD in these. If need long-life, use GT. GF is not very tolerant of heat and switching compared to GC/GD.

Cheers, Wizard

[bluto]

Re: Samsung DTB-H260F HDTV Tuner

Good news, the patient lives! Replaced the 1000uf and 470uf caps with new Panasonic FC caps and the filter cap with a Panasonic TS-ED series cap. The other three were replaced with some Panasonic NHG caps that i had lying around. Plugged everything in and it came right up. Another $200 device saved from a 10 cent cap!

Thanks for the replies and thanks to TC for this great resource!

[Krankshaft]

Re: Samsung DTB-H260F HDTV Tuner

Nice job!

Pana FCs are used to being baked they have a non-aqueous electrolyte they're troppers in hot PSUs.

[bluto]

Re: Samsung DTB-H260F HDTV Tuner

Kinda wish the manufacturers would give you the option to pay $5 more and get the good caps right from the start

[just2view]

Re: Samsung DTB-H260F HDTV Tuner

Thanks for your help. I'm an electronics novice but I do know how to use a soldering iron. With your information I was able to save my only high-def source by replacing the failure-prone 1000uf capacitor.

[bluto]

Re: Samsung DTB-H260F HDTV Tuner

Glad to see that my post is helping others fix their tuner. To make it easier to order new capacitors, here are the digikey part numbers for all the caps on the power supply.

All are Panasonic FC except the filter cap.

P10224-ND 1000UF 10V (qty 2) replace these two caps at the minimum
P10221-ND 470UF 10V (qty 2)
P11258-ND 330UF 50v (qty 1)
P10320-ND 33UF 50v (qty 1)
P10312-ND 1UF 50v (qty 1) polarity not marked on board, note before removing
P11695-ND 82UF 450V (qty 1) the large filter cap, replace this while you are at it

total cost should be no more than $15 with shipping

[PCBONEZ]

Re: Samsung DTB-H260F HDTV Tuner

.
Troopers
.

[MJA28]

Re: Samsung DTB-H260F HDTV Tuner

if this works with my tuner you guys will save me $250.i have the same tuner with the same issue(blue light just last 10sec)

[bluto]

Re: Samsung DTB-H260F HDTV Tuner

Glad to help. I am sure you won't be the last!

[MJA28]

Re: Samsung DTB-H260F HDTV Tuner

by the way. I thought bad caps look like a popcorn shape foam on top of the cap .lol

[Wizard]

Re: Samsung DTB-H260F HDTV Tuner

Fortune timing, I have a question how are these DTB-H260F tuner box fares on SD channels upconverted to 1080 in terms of picture quality? Better than built in scaler of TVs?

If one don't know, this is rare few models from some few makers that have NTSC and ATSC tuner with HDMI output

Cheers, Wizard

[Krankshaft]

Re: Samsung DTB-H260F HDTV Tuner

I like the picture what kind of stupid engineer would put caps that close to the V regs?

Using the PCB ground plane as a heatsink to boot what a stupid design. Unless you're using low wattage SMT parts that won't generate much heat there's no excuse for this. At least a dedicated heatsink can have fins and more surface area.

[Wizard]

Re: Samsung DTB-H260F HDTV Tuner

Krankshaft,

This two regulators are not linear regulator (LM2576) and have inductor coil for each and run cool. Some makers used poor capacitors that's all.

http://www.national.com/mpf/LM/LM2576.html#Overview

On this Samsung DTB.... box, these are not regulators, these are diodes. One have heatsink, while other one without.

Cheers, Wizard

[Wizard]

Re: Samsung DTB-H260F HDTV Tuner

Update: Googled bit more, now I found the answer. spit. :P

That box is ATSC only box and passes through NTSC to the TV. POINTLESS. Majority of plasma/DLP/LCD/rear proj CRTs now have ATSC tuners built in for last 3 years. Second, the most older units also don't have DVI or HDMI prior to this time (4 years or older RCAs and few other brands had DVI longer but is not HDCP compliant.

The KEY is there are people who are not happy with built in scaler doing very lossy processing on the 480 (SD via NTSC tuner) to fit 768 or 1080 panels.

I'm still looking and I plan to fix this NTSC scaling picture quality problem as I'm acquiring Sharp (backlit LED LCD 40") once I have money together say next month or so.
Reason we still have NTSC channels is we're in Canada and slowly getting few digital channels. Canada's switchover to digital is Aug 12, 2011, long way off.

Around 1970-1990 we had fantastic NTSC picture quality that is comparable to DVD literally before broadcaster ruined NTSC with overcompressed channels to pack more into limited bandwidth before reaching their head end that splits them and distributes them to subscribers after 1990 but quality is still better than built in TV's scaler.

Cheers, Wizard

[bluto]

Re: Samsung DTB-H260F HDTV Tuner

I think you are off a bit on your understanding of this box. The DTB-H260F receives either ATSC or clear QAM signals and outputs a high-def signal on either its HDMI or Component Video terminals (the latter of which all of the early HD-ready TV sets should have). I don't think HDCP is required due to the lack of any 'broadcast flag' rules ever taking hold. Output resolution is selectable for 480/720p/1080i. Optical and RCA L/R outputs are provided for sound. The s-video and composite video outputs are almost useless because the on-screen menus/channel numbers are not visible through them. I use this box with my projector (HDMI to DVI adapter) and it functions quite well in that role.

I don't think you are going to find a stand-alone tuner that can receive both ATSC and NTSC and pipe it out on HDMI/Component. As you point out, most TVs have this already built in, so the market for these type of devices was very small. Your NTSC broadcast (either ever fewer OTA or analog cable channels) receiving duties are best left to the TV or an old VCR. And of course this box is not to be confused with a 'coupon' converter box that can receive ATSC and output it to Composite/S-video or NTSC ch 3/4. On those beasts, Hi-def output was prohibited as a condition of being coupon eligible.

[Milt99]

Re: Samsung DTB-H260F HDTV Tuner

Hey guess what?
Went to turn on my H260F last night, same thing.
LED blivits and goes out.
My DIY bro is visiting and had a cap to replace the Samxon.
Replaced the cap and all is working.
Ordered 2 sets of the caps listed as I have another H260F feeding the projector in my HT room.
HDTV OTA tuners are getting harder to find and more expensive.
Thanks much for the great info!