2001 Sanyo DS27510 -Horozontal Line

[ZackN920]

Any one know where I could find a schematic and/or help me out with this TV. Usually I work on older stuff but since this is our main set, and it just keeled over, I told my dad that I'll give a whack at it before we go out and buy a new fancy flat screen. (which I'm against because I don't like the picture's)

Anyway's we've had this tv it's whole life and with 8+ hours every day for roughly the last 14 years, I'm surprised it never needed servicing years ago.
Earlier this week I noticed a Horozontal line appeared at the top of the screen with the portion right above it looking compressed. We thought it was a glitch because if shut off (and left off) for 5 or more min, it would be gone. But everyonce in awhile it would slowly come back while on. This evening though it came on fine, but within 2 minutes the screen suddenly jumped into that classic horizontal line... Vertical section of circuts has apparently failed. Not sure exactly though if it'd be just a cap/filter cap or some other issues. I don't know much when it comes to these newer televisions. Hell, I could use more knowledge when it comes to the vintage one's too.lol

Those of you that know these sets, please help me out.
Thanks

[rca2000]

You have a vertical failure.

Almost surely needs a couple of capacitors and the vertical chip. Possibly just bad solder connections, but sounds like by now the chip is bad.

Should be mounted on one of the larger heat sinks on the chassis. It will hav e from 5 to 12 pins or so on it. #'s such as LA7832, LA7838, or such, possibly something different, but likely available on ebay.

There should be a capacitor off of that chip, rated at 35 volts or maybe 50 volts, and 100UF or so, it WILL be bad. Replace this and the chip--and see if that helps. It is possible that the fuse resistor from the SMPS or flyback has opened--when the chip failed, and if toy have a meter, you can check and see of the 25 or higher voltage supply is there for this chip when power is on. If it is NOT there--a resistor off of either the SMPS power supply, or the flyback has opened, this will be a low value resistor, 10 ohms or less.

Sams has a manual, photofact # 4526

[radiotvnut]

What usually happens with Sanyo TV's from this era:

1. Cold solder connections on the vertical output IC (the IC will be a stand up IC that's mounted on a heatsink). Resolder the IC connections before doing anything else (you might get lucky).

2. Vertical boost capacitor fails and takes out the vertical IC and possibly the B+ feed resistor and the B+ diode. This capacitor will likely be either a 100uf or 220uf and it should be replaced, even if all you had to do was solder the connections. The symptoms of this capacitor going bad are lines and foldover at the top of the screen. After awhile, the condition of the capacitor will get worse and it will burn up the IC.

I don't have a schematic for this set; but, you should be able to google the part number of the IC and get a pin-out diagram. Once you have that, determine where the B+ voltages enter the IC and check those voltages (with the old IC removed). If the voltages are missing, trace the circuit back until you find the resistor and diode that supplies these voltages (usually off the flyback transformer). More than likely, the resistor and/or diode will be bad. When working on the set in this condition, do so for as little as possible to prevent a line from being burned into the CRT. Or, unplug the CRT socket or turn the G2 control on the flyback down.

Sanyo CRT TV's are usually pretty good and once you fix the vertical issue, it will probably last you for several more years.

[Username1]

hmmmm.... I have a Sanyo DS25390, I got it from my sister who bought it new....
She sent it to me for a buzzing sound it would make while on.... Turned out to be a
common problem with a bad cap on the standby supply that would run the relay
when the set is on.... Yesterday while watching the set I saw the picture fold up from
the bottom for a few seconds, then for the rest of the evening it returned to full size.
But you could see very tight compressed scan lines at the bottom..... I guess it's a cap
since the buzz was a cap, and I found many of this type of problem on the internet...
I imagine most Sanyo's are the same, and that if this cap goes bad completely it
will take out several other components....? Correct...? I guess I'm better off taking
this set out of service and replacing caps in the vertical...... When I got the set, it also
had the white glue on the convergence magnets dried and let go, I did a full convergence
on this tv, It has an outstanding picture, So I'm very interested in keeping it....
I have several back-ups....

.

[radiotvnut]

Resolder the vertical IC and replace the capacitors, especially the one I mentioned.

[ZackN920]

Hey guy's,
Thanks for the help so far. Honestly I didn't know these tv's had a chip, that dedicated to the vert. circuits.
Well, anyway's after work and some stuff I had to do, I tore the back off in the living room... WOW! This thing is DUSTY! Im a little surprised it never smelled(like when tubes burn dust). Also shocked at how small the board is for all the functions this tv has.
After some searching I found the Vertical Chip. It's a LA7841 chip with 7 pins.http://www.audiolabga.com/pdf/LA7841.pdf I found that one of the pins(#2) does have a bad soldier joint. Looks like it even broke loose, but looking at the surrounding board, it looks as if that pin's overheated some...idk. I also easily found that 35V 220uF cap too, that was close by.
Honestly I think it did kill the chip, like what radiotvnut said in#2, the cap likely went bad and took out the chip, because it did have an issue at the top of the screen before it went.

So basically, replace that cap and the Vert. chip/IC and see how it goes from there?

I was also wondering, how do I go about discharging the crt/high voltage in this set safely? without destroying anything. Normally, I would short it out on the chassis, but this don't have a full metal chassis.
Can I also disconnect all the wires that i can to pull the board out easily, without worring that i may destroy its programming(since these newer sets all have menu's instead of actual knobs that controll the settings)...like i said, I dont know that much about these newer one's
I havn't decided yet on the schematic. Sam's wants $22 for a copy and that sounds kind of expensive.
I got a few pics down below.
Thanks very much so far guy's.

[colectorad]

Originally Posted by ZackN920

So basically, replace that cap and the Vert. chip/IC and see how it goes from there?

Re-solder and test the current IC.

Originally Posted by ZackN920

I was also wondering, how do I go about discharging the crt/high voltage in this set safely?

Use the grounding strap that surrounds the CRT (look for the long spring).

Originally Posted by ZackN920

I havn't decided yet on the schematic. Sam's wants $22 for a copy and that sounds kind of expensive.

Use this. The schematic is on the last page.

[Marco-nix]

When the parts are not well ventilated, dust heated parts often .. I hope you gonna remove the dust Zack....Yesterday I found a 2001 Toshiba and the set was very dusty and she was dying because of it. I opened it and it was about 1/4 inch of dust .. I removed all the dust and now it works fine

[Username1]

That is pretty dusty.... I take the back off all my daily use sets once a year and
give them a vacuuming out..... Don't want that dust to make it easy for a short
to develop in the humid summers we have here..... You got a few years worth
of dust in there.....

.

[Marco-nix]

Yes indeed Username1..

[radiotvnut]

Also, the HV will attract dust. I can generally tell if a set is low hours or high hours by the amount of dust inside.

Concerning the vertical issue, replace the 220uf capacitor and resolder the IC. If that does not do it, replace the IC. If it still does not work, check the B+ voltages going to the IC and investigate from there. That vertical IC should be cheap; so, might be a good idea to order 2 or 3 of them for future use or in case you blow one up.

As for discharging the CRT, clip one end of a clip lead to the CRT ground strap, clip the other end of the lead to the metal portion of a good insulated screwdriver. While holding the handle of the screwdriver, gently slip the blade of the screwdriver under the HV anode cup and repeat several times. If the CRT is fully charged, you may hear a loud SNAP when it discharges.

You should be able to unplug the chassis without fear of losing any memory. As far as what unplugs, you have the degaussing coil, speakers, deflection yoke, the CRT socket board will unplug from the CRT, the HV connector, and there will be several ground connections that go between the CRT ground strap and both the CRT socket and chassis.

[Marco-nix]

You're right Radiotvnut concerning if a set is low or high hours.. 2 days ago i found a Toshiba : year: 2001 and when I removed the back, the circuit and the CRT was like new..I ask to the owner if he had this set since longtime and he said to me he bought new in 2001 but never played more 2 or 4 hours a day.. he has a new flat screen now..Anyway the Toshiba is heavy weight for a 27'

[radiotvnut]

I wonder if it's a real Toshiba or one of the Orion-built sets?

[Marco-nix]

Originally Posted by radiotvnut

I wonder if it's a real Toshiba or one of the Orion-built sets?

I can't say but the CRT is made by Orion yes.. so is it good or not ? I can't say . what do you think about Orion ?

[ZackN920]

Hey guy's, just a quick update.

It's BACK!!!! Thank ya'll very much! I'll get back to ya in awhile when I get on one of the PC's.