Sanyo 20EZ / Soundboard Question

[FrizzleFried]

Alright...I have a DK Jr. with a Sanyo 20EZ in it.  I ordered a Cap Kit from Bob Roberts (the real one mind you) as well as a Cap Kit for the Nintendo sound board.  This question is in regards to the sound board...but being that these two devices sort of go hand in hand,  I am posting the question here in the monitor forum.

Part of the Cap Kit for the soundboard includes two components with 3 prongs on each,  squarish with a hole in it.  It is fairly obvious they are to replace the two identical components on the sound card that is attached,  with a screw,  to the two metal plates which I assume are heat sinks...there appears to be THERMAL INTERFACE MATERIAL between these devices and the heat sinks.  Am I correct in my assumption?   When i replace these two components (please...what are they called?),  I am guessing I should add new thermal interface material,  right?  I have some Arctic Ceramique around as well as Arctic Silver...I imagine the Ceramique would be better as it is non-conductive.

Can someone confirm my assumptions or correct them?   

I was surprised at how easy it was to remove the monitor, frame and all from the cabinet.  I was also surprised at how much of a pain in the ass it was to remove the chassis from the frame (in comparison to the G07's i'm used to working on).

Also...when i am completed with this job,  can I leave the flyback metal "cage" off the chassis?  It covers the screen and focus knobs and I just assume leave the damn thing off.

Finally,  as I was taking the monitor out of the cabinet,  all the screws had a turquoise material in them that broke off as I unscrewed the frame bolts from the cabinet,  am I correct in my assumption that this monitor has never been removed and that those blue "glue" marks were put there by the factory?

[Ken Layton]

Those sound like transistors. In all my years of fixing monitors, I have NEVER had any transistors go bad on the sound board on Nintendo Sanyo monitors. Of course the capacitors on that board go bad though.

In general some transistors need "silicone heat sink grease" applied between the transistor and the metal bracket for proper heat transfer. Radio Shack # 276-1372 Heat Sink Grease is made for this purpose. You might also need the mica insulator for your transistor which Radio Shack also sells as # 276-1373.

On the Sanyo monitor be sure to put the metal flyback cover back on. It is needed for mounting the video inverter board on and for your own safety in case the flyback develops a crack in which high voltage 'leaks' out. Instead of leaking to your hand and killing you it'll arc over to the metal cage.

The turquoise stuff on the screws is simply locktight to keep the screws from working loose.

[FrizzleFried]

Thanks Ken,

I don't have an inverter board (it's hooked directly to a Nintendo DK Jr. PCB)... but I will replace the cage per your recommendation...I supposed I better adjust the screen and focus before doing so.

Would you recommend NOT messing with the transistors?  I only ask as they came with the cap kit sent to me from Bob Roberts...i'd just as soon replace the CAPS only.

[Ken Layton]

Don't bother installing those transistors.

[FrizzleFried]

Thank You Ken for your advice.   You are a invaluable source for information,  as is usually the case.  Have a great weekend.

[FrizzleFried]

It was my understanding that a CAP KIT usually included ALL new EL Capacitors?   I completed a cap kit last night on my Sanyo 20EZ using a kit purchased from Bob Roberts and there are roughly 7 old capacitors still sitting on the board?!

Is that normal with this chassis?   Do those CAPS not dry up?

EDIT:  His site lists the 20EZ at $5.00 then he has this under it:

20-Z2AW Color - Basically a 20EZ +
9 more caps as ordered by some folks   $7.00

I assume those 9 caps are what I am referring to?   Should I contact him and ask for those 9 caps (at an additional cost of course) or are they "usually" not bad?

It would suck to put this back together only to have to pull the damn thing out again to re-cap those 9...

EDIT #2:  I am attaching a picture from Bob Roberts Website identifying my chassis as a 20EZ.  I have circled 3 of the caps that DIDN'T get replaced...when I do a search for 20-Z2AW,  I get a number of hits indicating that this chassis IS a 20-Z2AW... which confuses the hell out of me because the picture attached,  from Bob's site,  what matches my chassis exactly and includes caps that I didn't replace in the same positions as my chassis,  identifys it as a 20EZ.

Now,  I guess they two can be one and the same?

Help!

[Ken Layton]

I have found those caps are indeed going bad from old age and I replace ALL the electrolytics on this chassis. Considering what a pain in the ass it is to get all those boards out to work on anyway, I replace 'em all.

Yes the 20EZ and 20Z2AW are generally the same, but I understand the flyback is different part # and comes standard with the video inverter board mounted on the flyback cage. The 20-Z2AW also has a red "push-to-degauss" button mounted on the chassis frame.

[FrizzleFried]

I don't have a push to degauss button...well now poop.  I am disappointed this cap kit DIDN'T come with all the caps.   What in the hell should I do now.  The only "electronics" store in my area is Radioshack which is a friggin' JOKE.

ARGH....

EDIT: I have a G07 cap kit sitting around somewhere...I wonder if I could use any of those caps to replace some of the Sanyo's...

It's OK to use a higher voltage CAP as long as the uF rating is the same,  right?

[grantspain]

correct you can use a higher volt rating,your only problem may be physical size

[FrizzleFried]

Alright...so I complete the CAP KIT and install the monitor.  I fire it up and GOOD NEWS...the geometry issue is resolved...no longer is the left side of the picture squished to a line.  Color is vibrant... good stuff...

BUT...

I still am getting a shimmer...its a very very very tiny wave going from left to right (top to bottom if the monitor was sitting horizontally)...it appears to cover most of the screen but it seems a little worse toward the bottom.   I have only had time to adjust the monitor a little,  but it seems that I MAY be able to adjust it out...last night I got it to be a little better,  a little less noticeable,  but it was still there.  I also curse this friggin' monitor as getting to the horizontal width coil while the monitor is in operation is next to impossible, if not completely impossible.   

Now,  the powercord is jacked up and missing the ground pin (yes...i've been careful while it was on)... and I plan on replacing it tonight...do you think this may have something to do with the shimmer.  Listening VERY close to the backside of the unit,  i THINK i can here a slight fast wavy sound....but not 100% sure...

[grantspain]

picture wobble can be caused by many things;
mains interference(no mains filter fitted) or problem with mains transformer
bad/missing earth
cap fault
mains transformer too close to yoke
interference from flo tube
i would start by disconnecting your signal input to see if your monitor displays this interference,disconnect any marquee lights,meter continuity of your earth from the input plug to the monitor frame/tube braid/neck card

[FrizzleFried]

OK...i replaced the power cord so the cabinet is now correctly grounded.   I still have the bloomin' "wave" issue.  I can adjust it out and it will look fantastic,  but then after a level or two it will come back.  I've even had it occur,  I then go around back and get ready to adjust,  pull out the trusty mirror and low and behold...no FRIGGIN' wave...so I go up front and take a look...sure enough...everything looks great...after a minute or two,  the wave re-appears.   After adustment it goes away only to re-appear again.

This wave is SO SMALL that my wife didn't even notice it.  I DO though and that is what counts damnit!   

Adjusting the Vertical hold will speed the wave up and slow it down... I am almost positive I've even REVERSED the wave direction with adjustments as it is now going from bottom to top (right to left on this vertical monitor) and I am damn near positive it was going to opposite direction yesterday.

Bob Roberts told me it may be a powersupply issue?

It's maddening as the rest of the picture looks so damn good.  With the smoked plexi on you can't even BEGIN to see the ever so slight burn-in on the monitor...the colors are fantastic, etc.

BTW:  Are Nintendo games supposed to take up the full monitor vertically?   I can't seem to adjust the horizontal coil to where it takes up the full screen...there is about 3" of monitor real estate top/bottom and I can't seem to stretch it any further?   It looks fine though and with the smoked plexi you can't see the monitor dimensions anyway.

[grantspain]

i have also seen this occur when the grounds of the jamma/psu are not linked,if you are using a switch mode psu you could try linking the mains earth and the ground connections

[FrizzleFried]

It's the stock Nintendo boards in there...no JAMMA...and it's in the stock configuration with the stock power supply (which is not a switcher,  right?).

Thanks for the suggestions though.

[modessitt]

Waves are usually a sign of an iffy power connection somewhere.  You usually see these referenced as a "hum bar" in Pac-Man machines, although I've seen them in other games as well.  Here are the steps to remove it in Pac-Man.  Maybe they will help you.

But first, remember that the Nintendo monitor should be plugged directly into the 110V outlet on the power supply.  Nintendo monitors don't run on 120V like normal monitors, so I would double check that first by reading the voltage at that plug (there should be several so make sure it's plugged into the right one).  (Just in case Ken hasn't already mentioned this.  I forget.)

The next step would be to replace all your fuses with new fuses (if you haven't already) and make sure that they are mounted securely.  Clean the fuse contacts with a bit of sandpaper or cardboard emery board while you have the fuses out.  A lot of times, this will remove your wave.

Then you should try gently "flexing" your edge connector while someone who knows what the wave looks like watches the screen.  If the wave goes away, then you might want to a add a little solder to your power and ground tabs to get a better connection.

If none of these options work, you should gently tug or "rock" all the connectors, both on the power supply and game board as well as to the monitor (i.e. degauss connector, video input connector, etc.) and see if anything causes your problem to go away (or get worse).  If you find a culprit, inspect the solder joints for needed touchup and the pins for any discoloration which should be cleaned off.  Any connection that isn't perfect can cause a wave to appear on your screen.

Hope this helps.

[FrizzleFried]

OK...I turn up the screen pot to max...I can now see the vertical lines...if I unplug the board power the vertical lines are static...when I plug the power back in,  the vertical lines jump around a bit...not really a wave,  you can't see any kind of picture enough to determine a wave...but the vertical lines DO move a bit...

...should I assume the problem then IS in the PCB...likely the power somewhere?   I did a quick check of the one fuse I could find (at the back of the cabinet where the powerswitch/cord are.   I also disconnected and reconnected all the power connectors...

...no go.

[Ken Layton]

It's very possible that the main (largest) filter capacitor on your monitor is going bad. It's not included in capkits and I've seen them all dying of old age now.

Also the original Nintendo gameboard power supply (gold box at bottom of machine next to the power outlets) is of the age where it's capacitors need to be replaced also. It is indeed a switching regulator power supply, but it's an early more primitive type than the Peter Chou types.

[FrizzleFried]

Hi Ken,

Any suggested plan of action?   I see that I can get a modern switcher with conversion kit for $45 from arcadeshop,  but i'd hate to buy that only to find my problem still remains.  Is there a way I can isolate this issue without another Nintendo board or PS to switch with? 

I guess I should pull the darned monitor out again,  pull the chassis,  find out the filter cap spec and order one from somewhere (I an in Idaho and there isn't any electronics parts stores aside from Radioshack which is a joke)...

That'd probably be my least expensive plan of action I am guessing...

I was hoping someone would tell me "Yah,  when you turn up the screen pot,  the vertical lines (on a vertical monitor) shouldn't be moving as they are when you unplug the PCB...which would point me toward a power supply issue (which is what Bob Roberts thought it may be as well).

I am torn right now because I am trying to decide on if I should just MAME the damn thing and run only the 3 Donkey Kongs on it and convert it to a "Multi Donkey Kong"  (it would be much cheaper to MAME it than to use arcadeshops programmable JAMMA board).  My other option would be to buy a 48-in-1 since it too has all 3 Donkey Kongs...but I dunno...it's going to be a for my game room only...not on site...so....ARGH...

My wife thinks I am being entirely too anal.  She can BARELY see the wave but it does nothing but command my attention every time I look at the damn monitor.

I can adjust it out...it looks GREAT for about a level or two then it comes back.   It is affected (the speed of the wave mostly) by the vertical hold pot.   Hell, I am almost positive i've switched the waves directions before...

All this points me toward a bad PS,  but then again,  I am an electronics newb..

 

[FrizzleFried]

ARGH...the entire screen is now showing a slight "viberation"...but it's more pronounced when the "wave" has been adjusted down...I am at my wits end with this.  I double checked all connections...no fix.  I wiggled all connectors...no change.

>cries<