Quick opinion needed on Super Neo 29 monitor - Pics included!

[lessthancj]

Hi everyone it's been a while since I've had time/money to work on my cabinet but now I'm back at it. Unfortunately after turning the cab on for the first time in a while half of the monitor is dark. I think it's because I accidentally broke the brightness adjustment knob somehow but I'm not 100% sure. Also I disconnected and reconnected every plug to the power supply and all the button wires so I wonder if that may have caused this.

Here's a picture of the monitor....
http://img132.imageshack.us/img132/6626/sn850504.jpg

And here's a picture of the brightness knob that I broke  D*=
http://img44.imageshack.us/img44/5239/sn850505.jpg

If anyone can recognize what this problem is I'd really appreciate some advice on what to do and where to look for parts. Thanks in advance!

[MonMotha]

Well, I'd start by replacing the brightness pot.  Seems like an obvious thing to do.  If you don't have the one you broke off handy to read the value from, I can check mine this weekend.

[lessthancj]

Thanks for the offer but I do have the brightness pot and it reads "J202 G". What websites do you recommend for spare parts? Also how do you reattach a single brightness pot? It looks to me that it might be easier to replace the whole row of pots, but I'm not sure.  :/

[MonMotha]

Sounds like that's probably a 2kohm pot.  If it's not destroyed, you could measure it.

To replace it, find a suitable one, remove the old pieces from the board, and solder in the new one.  You'll have to find a replacement that's mechanically close enough to fit in some way.  Places to look for spare parts will vary with your location.  In the USA, check the various "hobbyist arcade suppliers" such as Bob Roberts as well as full-line electronics distributors such as Digi-Key and Mouser.

[lessthancj]

Thanks a lot for the advice. That doesn't sound too hard to replace. Now I just have to spend some time to find a replacement. I wish I didn't pile things so carelessly into my cabinet while I wasn't using it-then all the pots would be fine. If anyone on the boards knows off hand where to get replacement pots let me know.

[lessthancj]

Nm I found some 2k ohm pots that I think will work from Bob Roberts website. I'll hopefully post some pics of a working tekken tag in the future.

[Unholyknight]

Just so I don't start a new thread on the same topic:

I just moved my arcade machine and when I got it setup in its new home the monitor wasn't working.  Upon inspecting the inside of the projection system I found that the H. Size and V. Size pots had been broken off.  The monitor doesn't seem to want to do anything for a game, but when in convergence mode shows a single white line along with a red circle / a blue circle / and a green circle, in a straight horizontal line above the white line.  I'm assuming since it isn't getting any sort of horizontal or vertical value from the H. Size and V. Size adjustments that it is simply freaking out.

These pots are on the 41" Mutsubishi projection monitor inside of my Megalo 410.

Any ideas as to what sort of resistance I need for the following pots?
J202 t - V. Size :: is this going to be a 2k ohm pot as well?  I don't know if the t and g signify drastic differences. According to Mouser, the J202's in general are 2k ohm pots.

J103 (looks like delta) - H. Size :: All I have to go on here is that Mouser has all the J103's listed as 10k ohm pots.

[MonMotha]

The reference designator on the board (the Rnnn number) has nothing to do with a part number.  They are assigned, usually sequentially, but the designer of the device.

You'll have to find out what the resistance is supposed to be from the old ones, a manual, or somebody who has one.  Make sure you replace it with a linear taper model, not an audio (logarithmic) taper model.

[Unholyknight]

The reference designator on the board (the Rnnn number) has nothing to do with a part number.  They are assigned, usually sequentially, but the designer of the device.

You'll have to find out what the resistance is supposed to be from the old ones, a manual, or somebody who has one.  Make sure you replace it with a linear taper model, not an audio (logarithmic) taper model.

The numbers aren't the assigned numbers on the board (which are RE27 and RE14 on the circuit itself), they are printed on the pots themselves.  The numbers printed on the board are, as you said, in a sequential order on the circuit board itself.  I asked an IC supplier and they told me the numbers on the potentiometers were in reference to their resistance and validated those numbers (the 2k ohms on J202 and the 10k ohms on J103).  I'm assuming the numbers are not there to throw you off, especially since resistors have a method of reading their resistance in their 3 digit number.

Here is a picture for reference:


I found 2k ohm and 10k ohm pots on Bob Robert's site and they look identical to what is broken on the PWB for the monitor.  From looking at that picture do you think I still need to get in touch with another megalo 410 owner and have them measure the resistance or do you think I've got the right information?  I want to be as sure as I can with these pots, but if they don't fix it I have a backup plan that requires a bit of elbow grease.

Thanks again for the help, let me know if I'm wrong! I can be a little stubborn at times, haha.

[MonMotha]

Ah, I see.  Those numbers are usually in a specific format.  The first 2 numbers are the two significant digits, and the last number is the multiplier (aka number of zeros to follow).  So, a "202" is 2000 ohms, or 2k ohms.  A 103 would be a 10000 ohm or 10k ohm pot.  You get the idea.  If the pot isn't totally broken, you may still be able to measure it to confirm if you can't read or there are no markings.

[Unholyknight]

Ah, I see.  Those numbers are usually in a specific format.  The first 2 numbers are the two significant digits, and the last number is the multiplier (aka number of zeros to follow).  So, a "202" is 2000 ohms, or 2k ohms.  A 103 would be a 10000 ohm or 10k ohm pot.  You get the idea.  If the pot isn't totally broken, you may still be able to measure it to confirm if you can't read or there are no markings.

202 is shot and and measuring it was pretty much not possible, I tried the 103, by attempting to put it back together or bridging it back together, but that failed as well.  I do have a backup project in mind if the monitor doesn't come back to life so the cabinet won't be a waste either way.  I think my best option is going to be to go forward with a 2k and 10k assumption and cross my fingers.

If the monitor never comes back to life it'll be scrapped and I'm going to make an attempt at an LCD swap instead. A fun project, but definitely the more expensive route.

Just a quick edit, this is what the monitor looks like currently when in convergence mode:


The single white line is the compressed convergence grid, and the red/green/blue dots are the current brightness levels (usually show below the grid), but since the h and v size's are shot they're just mashed down into the center.  I've seen the picture shrink to a single line on a monitor before when just the h size went out and this looks about the same. That TV was under warranty, got a repair, and was right back to normal.

[Unholyknight]

Just a follow up post.  Thanks for your advice MonMotha.  I finally got the board soldered with new 10k and 2k pots and the monitor is up and running once again!