Need help with convergence problem

Sounds like you have hardware failure in the convergence circuit. Some combination of the IC's, fuses, and/or resistors has failed. Repair cost is $250-$400 parts & labor.

Hammer

AKAI rptv is basically a Samsung that's been rebadged. The entire board could be replaced quite easily by a non-Tech as long as you be careful to do it when the set is unplugged and get the wires plugged back in exactly where they came off. A full manual convergence should be done afterwards.

The problem will of course be getting your hands on the board as a consumer. Only suggestion is try Samsung directly or http://www.ptscorp.com/television.html . The board you want is usually called the Power Board, you don't want the Main Deflection or Signal Board(s).

Hammer

Sorry I don't have adequate documents to supply you with a part number for the board. Full convergence will be easy. Many places to find codes and help, starting with http://www.keohi.com/keohihdtv/brand...sung_tips.html

Hammer

The board will come complete with the IC's. PTS re-manufactures boards. Not sure about the part numbers & price differences, have to contact that dealer and ask.

Hammer

Apparantly I have the same problem. Same model tv. Were you able to fix yours?
The red has a severe bowtie shape. I actually saw the change happen. The user convergence menu control has no effect on red but does move the blue. From information in this thread and elsewhere on the web, it sounds like the STK392-40's are a common failure causing this kind of convergence problem. I have ordered (2) STK392-40's, some pico fuses,and some heatsink grease. We'll see what happens
The TV's about 4 years old and this is the first problem.

When I first got this Akai PTH5498 tv I ordered a service manual which came from Samsung. The manual is the worst service manual I've ever seen. It looks to me like there must be some other manual(s) and this one is just some supplamental information. There are schematics and block diagrams but it's incomplete and theres not enough information to tell how it all fits together or whats on what board. There is a partial schematic which will tell me which STK392 affects the red. I'm gonna try changing just that one first.

Web addresses found for PTS don't work. Are they still in business?
John

No, that's sounds like a typical Samsung manual alright. Try figuring out their parts list. Now those are a doozy.

Ok, The parts are not here yet but I have confirmed the fuse to one of the STK's is blown. Would I be nuts to try replaceing the fuse without changing the STK. In a STK392 convergance circuit, is it ever just the fuse?
John

You can try it. Most of the time the fuse blew for a reason.

It's fixed. I tried the jumpering a new fuse first and it blew instantly. Changed one STK392-40 and it's blown pico fuse. Red was shifted to the right but was corrected with the user convergence menu. I probably need to do the 56 point convergence but SD looks ok for now. Haven't looked at a HD source yet.

Thank you all.
John

Purchased The Akai/samsung Pth5498 4 Years Ago. I Have The Same Issue, However I've Had A Tech Out And He Said It Was The Crt Socket Gone Bad. The Part# Is Aa41-00406a. He Told Me They Purchase From Tri-tronics And They Didn't Have The Product. Does Anyone Know Where I Can Purchase This Product? And Did You Get Yours Fixed?

did anyone have any luck with replacing the board? I'm having the same problem with my TV. Samsung HCM422w

johnd393,
You know where this fuse it located. I replaced the STK 392-040 and the 3.9 ohms resistor RZ145 and RZ144 by RED Convergence plug was open. Any reason why this openned.

I sent a PM. The fuse that blew on mine is between a couple heatsink fins. I guess i was lucky I didn't have a bad resistor. I never found them to check. Apparantly when the STK chip fails it takes out the fuse and sometimes the resistors.

I am also lost in the land of Samsung/Akai. Because of your comments I have located the convergence chips, but am unable to find the fuses mentioned. Since I live in a one horse town I would like to get all parts necessary on one order, (shipping, mad wife, time, mad wife, must be my fault). Not worried about a couple of extra $$ for fuses, please give Newark part, # so I can order with chips. I did find the resistors that were mentioned but mine are undamaged. nothing resembling a fuse between heat sink fins, but I am old and might not know what a modern fuse looks like.

The fuses are very small and look more like 1/4 watt resistors than fuses. If you search the web for "pico fuses" you should find some pictures.

Wow, you guys are great. Found the fuses right away after you told me what they look like. One of them is blown on the red circuit, Now the onlest problem I have is the fuse size. It looks like FD 1018 is printed on the board

Belay the last. Was able to read the fuse size after I removed it from the board. For anyone else out there looking for this information they are 3.f amp pico fuses.
---Jack---

I am having the same convergence problem.. i checked the fuses by the STK 392-040's and none of them where blown... could this just be a problem with my convergence module then? PN AA95-01799G

Hello Everyone,

This post is pretty far down the thread, but I hope someone is out there. I have the infamous AKAI PTH5498 with similar convergence issues. Convergence cannot be adjusted for either color. I can select between the RED & BLUE, but I can't adjust anything. I have some electronics & neat soldering skills, but I am no wizard here. One thing I have noticed about this issue is that there are many posts in many different sites & forums for this same issue with many Samsung/AKAI sets.

Another thing is that many people seem to be pointing to the STK-392-040 ICs as the culprits and/or the many surrounding resistors located on the center of the three main circuitboards. Though this may be the problem in many situations, many people seem to be confusing this center board with these huge ICs on heatsinks as being the convergence module board, when the convergence module is actually located on the LEFT of the three boards when viewing the set from the opened back. The convergence module is inside one of those metal boxes perpendicular to the circuitboard, part# AA9501799G available at www.partstore.com. It plugs into the main board similar to the way a small PCI card would plug into a computer.

Anyway, here's my situation: I have carefully replaced both STK ICs and checked all the surrounding resistors. I found all resistor values to be fine. There seem to be very many resistors in this area ranging from 1 watt to as small as 1/8 watt. I could not locate the PICO fuses that others have found to be blown. Any clue to their exact whereabouts would be greatly appreciated (maybe grid coordinates if possible). I put everything back together and the set functions exactly the same way as outlined in the first paragraph with both brand new STK-392-040, no change in function at all.
I guess it's better than SMOKE, but I have gone exactly nowhere after many hours of work. Any help here would be greatly appreciated.

Thanks to the research gathered from this and other online threads I was able to sucessfully repair my AKAI PTH5498 54" HD projection TV. It was a very frustrating road and I almost lost hope. If anyone has the same problem feel free to contact me. I am not a tech, but I do have some soldering & testing skills. One thing I would advise is to make sure that the convergence circuit with the large ICs STK-392-040 is good before purchasing the $100 convergence module like I did. Chances are that the convergence module is NOT the problem. I would try testing both 3.5A pico fuses located under each of the large heatsinks which support STK-392-040 ICs. If needed, I would replace these with their SLOW BLOW PICO II equivilant. I would also check the surrounding resistors in the circuit. Replacing the STKs is a tedious task. Soldering MUST be precise and clean. If you have a bad fuse, replace it and try it in the set before replacing the ICs. The fuses may be your only problem. Since the IC run so hot I am going to look into cooling fans for this area GOOD LUCK!!

shademasters (or anyone who can help),

I think I need to replace my convergence module for my Samsung HCL4715w, would you mind taking a peak at my thread (pictures) to confirm this is indeed what I need to get to fix it: My Samsung HCL4715W Broke

Any advice on the best route to go with this?
I found my part number for sale online: AA95-01799G

Is there any soldering requirements for replacing the whole board?
Also you mentioned the pico fuses, whats the best way to test these?
Also I assume I am going to need to get the service manual, you know of any places where I can get it cheaper then what ServiceManuals.net is charging ($23.99 for the HCL4715WX/XAA)?

Thanks,
-BassKozz

Hello BassKozz,

From your photos, your TV looks exactly mine did. I wouldn't waste money on the convergence module for $100 approx until you do some testing on the circuits surrounding the 2 large ICs attached to the large heatsinks they are very easy to locate, and they are probably located on a different board than your convergence card is. We have different TV models, but my ICs are STK-392 040. My ICs are located on the center board, while my convergence module is located to my left viewing the set from the opened back.

With mine, I tried purchasing that AA95-01799G part looking for an easy fix, but it didn't change a thing.

If you can post me some photos of the inside of the set I can help you locate the parts you need to check. you can email me mrshades@comcast.net.

Good luck,
shademasters

Actually thanks to this thread, I found out the same, it wasn't the AA95-01799G board I needed but instead it was this board AA95-01846D:


(Click to see larger picture)

I've already gone head and purchased this board from partstore.com: Here for $84.82

The problem I've run into now is removing/placing my current board...
I've already purchased the servicemanual (use-less), and I've cracked open the front of my TV (where the speakers grill is)...
Main
Left/Center/Right
(Click to see larger picture)

The AA95-01846D board is located in the center:

(Click to see larger picture)

In the picture you'll notice that where the RED ARROWS are pointing there seems to be a lip of plastic stapled to the bottom blocking the tray from easily slid out of the enclosure. If you notice where the BLUE ARROW is pointing, there seems to be a clip holding it down, I can't tell if there is one of these clips in the back as well? Also there are screws holding the board down as well (not pictured).

I am trying to figure out if I need to remove the back of the TV as well? Or should I be able to remove/replace this board from the front (speaker grill)?

Thanks for your help,
-BassKozz

hey basskozz,

i was curious how you made out with the parts that you purchased. i hope that you were successful. i am having more issues with my pth5498 akai. i replaced the convergence ics stk392-040 as well as pico fuses with success. the convergence was repaired and everything worked fine for about 2 months. then the tv would start cycling on and off, but not fully turning on- all the while making a squealing noise and relay click as if trying to turn on. this can only be stopped by unplugging the tv. on occaision, the tv will come on fully during this process. finally the tv did this routine one more time and came on, but now the sound is gone completely and i have to use the surround sound amp to hear the tv. other than this everything works fine and has had no problem other than the sound. no more cycling anymore. what could be the problem here? could there be a short that i wasn't aware of during the repair? could there be a problem with me substituting slo-blow pico II instead of the originals? I noticed in another forum a guy had used the slow-blow pico IIs and had a sound problem shortly thereafter. what board controls the sound? should i be happy that the tv works at least and forget the sound? can anyone help? also does anyone know if it is feasible to connect a cooling fan to this unit to keep those stk ics running cooler? if i used a regular computer fan where coudld i connect it within the mainboard circuitry?