CurtPalme.com Home Theater Forum

[PaulB]

Hi,
Tech Bulletin TB98-02 refers http://www.curtpalme.com/docs/ElectrohomeMarqueeTechnicalBulletin_Tb98-02.pdf

Just what resistor is supposed to go here? It mentions a 10k resistor but no mention of wattage or tolerence (Or am I just being stupid!).



This is the resistor in question, photo from Jaehong Lee's site.

Many thanks
Paul

[tse]

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=PPC10.0KXCT-ND

is the exact part. The part isn't critical, though. Any 10K resistor would do the job.

Scott

[PaulB]

Thanks Scott, thats just what I needed to know!

Paul

[Nashou66]

It also depends on what board you have Paul. you may not need it. Make sure you check the bullitin for what boards are affected.
And while your on that board you might as well put in the TLE2074 chips in. lower noise and chaep upgrade to the MC34xx chips which were the component that would fail on those board and cause a short on the +/-15 rail. Then you wont have to worry about that resistor and have a lower noise floor for the focus modual.

Athanasios

[Nashou66]

Also on that board change out the 6 470uf electrolytic caps with 1000uf same voltage or maybe a bit higher. this tightens up the focus a bit. I changed almost all the caps. the two 470uf power rail caps same value higher volt and temp, the 3 2.2uf 250 volt to 2.2 305 volt, and the 6 22uf(some have a 1uf cap) to a higher voltage and temp same value.

Athanasios

[PaulB]

Hi Athanasios,

Excellent information as usual and noted for future use

However my soldering skills are less than zero at the moment due to my total incompetence and inability to tin a tip! Having said that, how did you remove the old MC34xx chips, one leg at a time or the whole lot at once? I'd imagine the whole lot using flux - I know the theory, been watching lots of soldering video's the past week, still can't tin that tip though!
Paul

[Nashou66]

I bought a desoldering iron that is great for through hole parts like those op amps. i just go from the underside put the hole in the iron over one of the pins of the chips and release the compressed bulb on the iron, then I squeeze the bulb once more over a metal dish to expel the removed solder( Make sure you do this before you compres the bulb over the board I spewed out hot solder all over once ). I never tin my tip. For resistors i stick the leads into the flux and then heat it up to burn it off then i just put it where i want it and use the thinest solder i have . I heat the lead and touch the solder to the lead not the iron. this way the solder flows right on to the part and doesn't glob up on hte iron. I do the same with the chips, but don't stay to long on a chip pin i try to line it up touch the pin with the iron then touch the solder to the pin and pull both away. and then retouch the pin one more time with the solder to make sure it flows down the pin to the pad. No longer than 5- seconds on the pin with the iron. i use a 30 watt but some times i switch it to 15 if i need to stay on a pin longer but it doesn't flow as well that cold.

Athanasios

[PaulB]

[Nashou66]

I watch in between mods, this way I assure some sort or reliability to what I have done. So far so good. no smoke anywhere yet I am still waiting on the resistor change for the HVPS i think they finally shipped the 680kohm Ohmites to try in place of the 560k's. we'll see how that goes.

Athanasios

PS. for gods sake yes watch it! half the fun of improving the beast is to be able to quantify if the changes you make do actually improve the image quality....but i know most of this is for reliability though;) yeah right !!

[JustGreg]

[PaulB]

[JustGreg]

Thanks Paul!

Greg

[Nashou66]

yes TI will give you 5 free chips as samples if i were you fill up your entire available parts request withy these chips as they allow you up tom 8 part requests.
TLE2074 14 dip(FCM) any type, TLE2074 14 DW{(wide body)CLM and VIM 2035-03p)} Opa4134(CLM, VIM) TLE2072 8dip(VNB) TLE2072 8soic (2006-03p Vim.s)
TLE2071 (Vim ) Opa2134(vim) Opa134( vim). look at your boards and decide if you need the DIP or the SOIC and some have the wide body SOIC chips like on the newer CLM,VIM's, so you can get 40 chips for free!!!! I said i was a repair man and used the chips as possible upgrades but needed to test. you need a profile to set up.... the opax134 series dont come in dip any longer but are the better chip.

hope this helps

Athanasios

[JustGreg]

It helps alot. Thank you. I noticed recently while cleaning the lenses, with the 8500 powered on but no source turned on, that I have alot of noise (?) in the blue and green tubes. The red is fine. The noise is in the form of slightly downward angled horizontal lines that aren't moving up or down...just sitting there. The raster however is really noisy.

As it's only the green and blue would that help anyone here pinpoint where the possible problem area is? (such as HVPS, VIM, or neckboards)
Again, thanks for the info. That list represents a heap O' soldering for sure.

Greg

[Nashou66]

Hmm? Not sure about the wavy lines i never had that problem. The blue And the green always have that mosquito noise. Or the sparklies. The vim and the neck boards can be helped a bit with once again those lower noise chips and the ceramic resistors in the neck board to replace those carbon composition ones. Beefing up the de coupling caps on the vim can also help. I added 4.7uf tantalum(A case) and a 100pf silver mica cap on those decoupling caps for the rgb op amps but i also changed the amp itself,and i changed out the 100nf cap with a .1uf tantalum cap(A case) Added inductors to the power rails for the +/- 5 and 15 volt rails and some other cap upgrades on that board(2005-03P). I ahve another theory on the noise on the blue and the green and why the red is always sharper and cleaner than the other two tubes. The HDM has high voltage that i think cause's some kind of emi or rf noise that affects them. I read some where that one marquee owner noticed that the image improved if he kept the quad board installed even though he doesnt use it. the HDM is directly above the VIM if this board is not there. The board act's as a EMI RF blocker since it is predomanantly copper in the pcb. he also had removed the ability of the VIM to access the quad board . I cut a pice of sheet metal out to the size of the vim and applied some carpet tape to one side and then some copper flashing i got from home depot . I didnt notic anything but if there is some noiuse this shold help block it. I plan to add the copper flashing to the HDM housing as well in an effort solve the sharper red than green or blue and reduce the noise. Also the green tube has the HV splitter sitting right ontop of it. I will also try to shield that with copper on the underside of the plastic that mounts it to the tube. I might even cover the outside of each plastic tube housing with the copper. Its very thin so it might need a few layers not sure. Thsi is all just part of my quest to lower the noise floor of my marquee. I should start a new thead with all this stuff. its all scatterd around on both forums. what do you guys think?

Athanasios

[CRT_Ben]

[9kids]

[AnalogRocks]

I sugested a stickey for the mantinence threads to make them easy to find.

Curt's responese was:

[AnalogRocks]

I sugested a stickey for the mantinence threads to make them easy to find.

Curt's responese was:

[9kids]

I think Athanasios's is boarding on more than just maintenance & upgrades and into the mild mods and tweaking. I would love to be able to have a open discussion thread about what he is trying. I guess he should just start the thread and see if anyone objects.

[Nashou66]