Recent rash of 20EZV failures

Dokert

Well-known member
Joined
Jun 3, 2007
Messages
12,751
Reaction score
141
Location
Arlington, Washington
Lately there has been a rash of 20EZV failures, all with the same symptoms. It would seem that all of the same parts have been replaced. There is a common element here that is being missed by all of us, and I am not sure just what it is at this point. After stepping back and taking a closer look, let's start here....

1. The Sanyo 20EZV needs to be run through a 100vac isolation transformer. (Will it work just plugging it into a 120vac wall outlet? Sometimes it will, and sometimes it won't. Will it fail running it on 120vac, even with an iso? Yes, it may work great for 6 months or 6 seconds but it will fail) What failed because I used a 120vac outlet? Who knows, looks like you will need to go back to the beginning and start over.

2. Donor chassis' are great to have around, but some things should not be used from a donor chassis to effect a repair. Pulling the C606 filter cap from a donor chassis is a bad idea, because there is no true way to verify that it is good. The same can be said for pulling IC601 from a donor chassis. D601-D604 is a different story, because they can be proved to be good. So in short if it can't be proved good, don't pull it from a donor chassis and install it in the chassis that you are trying to repair.

3. IC401 & IC601 both have very small traces, and it is very easy to crack/break one of the traces when replacing these chips. In addition it is also very easy to get solder splash across more than 1 trace, creating an unwanted solder bridge. Don't be afraid to put these sections under the magnifying glass to verify your work.

4. The flyback replacement can cause a lot of grief. Some people unknowingly "Man-Handle" the old fly when trying to remove it from the chassis. The problem is that flexing the board to much can cause cracked/broken traces anywhere within the area of the fly. The fly should come off the board with minimal force, if not you need to go back and remove more solder. Another problem that I have seen is people not marking the flyback wires, and hooking them up backwards. How does this happen? Doorbell rang, kids were fighting, dinner is ready, buddy called, etc. Mark the old wires, and the new wires to make sure that they will go to the correct locations.

Sorry if this seems like rambling, just trying to shed some light on the subject.
 
I know I'm guilty of plugging mine in without the isolation transformer when I was rebuilding the chassis on my bench, I thought I would set the B+ while it was out and all easy to get at.. I wondered why the voltage was so jumpy when the brightness was turned up.
It's nothing like that when it's not at 120v input, it simply didn't occur to me at the time. Damn them for putting that plug on the power cord anyway lol.
 
One more thing of note.... (Thanks for reminding me)

5. Never ASSUME that the B+ is good after a cap kit on a Sanyo or a Sharp. Verify, Verify, Verify, that it is at 108vdc. Esepcially if you have installed a new Flyback whether it is "New" or "Used" from a donor chassis.
 
It doesn't matter who is guilty of what? We are all guilty of leaving what we individually consider minor details out of our "help" posts. We are all guilty of assuming that each of us remembers the basics of a specific piece of gear that we are trying to repair.
 
They do seem to "feel" cheaper than a wells or something else. Just the thinness of the board screams cheap. I always pick them up with 2 hands to keep them from flexing too much, and try not to flip them around too much when doing a cap kit.
 
1. The Sanyo 20EZV needs to be run through a 100vac isolation transformer. (Will it work just plugging it into a 120vac wall outlet? Sometimes it will, and sometimes it won't. Will it fail running it on 120vac, even with an iso? Yes, it may work great for 6 months or 6 seconds but it will fail) What failed because I used a 120vac outlet? Who knows, looks like you will need to go back to the beginning and start over.


Here's my experience...

http://forums.arcade-museum.com/showpost.php?p=933260&postcount=12

Edward
 
Back
Top Bottom