Sanyo 20EZ Picture Weaving

Sanyo 20EZ Picture Weaves

by Bob Roberts

Once something is posted to the internet it stays there forever & is continually referred to over & over again. Just when you think it is dead it rears up again to prove it was never buried. I've had my share in several cases. When someone cannot find their problem they jump to it's a defective part. I've been hunting for a defective part for over 50 years & have not been lucky enough to find one yet.

First it was power supplies which are tested here before they ever ship out & I've yet to find one bad from the get go, but still test them all. At first, I allowed several to be shipped back for retesting. I opened one & found everything fried inside! Contacted the person & got the story of lightning hitting a transformer outside & frying all his appliances in his home. That's not a defect in the power supply?? Another had 120VAC hooked up to the 5VDC output... turns out that wires were transferred from the old one position for position without regard to the label. Power supplies are not universal in their terminals... 5VDC may be the top terminal on one while being the bottom terminal on another, or anywhere in between. You have to arrange connections accordingly. This is why we hand wire all of our linear PS to switcher adaptors... you can hook them up to any power supply & are not obligated to buy one certain power supply with corresponding terminals. Defective power supplies to date: none.

The next case was the 7905 regulator that was posted as being defective. Turns out that most of the cases reported did not even use the -5 volts for the game leaving the reg unloaded under power. Did a page on that one & still it comes back at least once a year. Defective 7905s to date: none.

Then it was flybacks... I was shocked to see that monitor repair shops were jumping in on this defective internet legend. When several of the community repair services said that flybacks they had installed did not work I had them send them back to me for testing. I grabbed one of the $15 parts chassis' I had on hand & tossed the first one in thinking I was going to have to do other repairs to the chassis just to check the flyback. To my surprise it fired right up & survived a 24 hour burn-in after being told the flyback was dead. I had no sooner returned it when the second came in.... popped it right on that same chassis & although it was reported dead it too fired up & passed burn-in. After doing this several times I had to put a stop to it... no defective flybacks were found & it was a waste of time & postage. The first thing you need to do after installing a flyback & coming up dead is to check over your work & be sure that there are no cold solder joints & that even the good solder joints have continuity to the next component in line. Many times in pulling the old one out a trace will get a hairline crack breaking continuity from the flyback terminal to other components in the circuit. Defective flybacks to date: none.

That brings us to the last one that keeps returning on a regular basis.... the LA5112 regulator found in the Sanyo 20EZ. Way back in the last millennium when someone could not find the cause of the weave on their monitor someone suggested it was a defective component from us. I covered this one more than any other rumor because it turned up more than the others combined due to the fact that this monitor is prone to that problem & has several natural causes & a few man-made ones. I've ordered from no less than 3 sources & different batches & still it persists. I've tried them in monitors & they work find. I've had 2 that were diagnosed by shops as definitely bad returned & tested & they both survived 48 hour burn-ins with flying colors. Outside of all the extra work & steps I took was the fact that many reading this for the first time went to the trouble of buying replacements at double the price & ending up in the same condition after installing them & those who spent time in pulling OEMs off other chassis' & installing them in the questionable one only to find no difference. Defective LA5112 to date: none.

Your 20EZ has a slight weave to the pic then in order:

  • Cap Kit
  • More often than not this will take care of your weave.

  • B+ Filter
  • If bad easily spotted, but weak from declining value just a slight weave.

  • Regulator LA5112
  • Care should be used in replacing this in-line or your work could be a problem.

  • Current Limitter 2SD1090
  • This is a less likely suspect, but nevertheless it has been found to be the source of a weave.

  • Flyback Xformer
  • The only way we have proved out this cure is by substitution.

  • Pic Tube
  • Heater to cathode short. 50/50 using a CRT restorer. Anywhere from unsalvageable to 1 year up to multiple years after booting.

Toss this list out the window if you created a man-made problem such as shorting something with a screwdriver, forgetting to cut spews from a cap before reinstalling, shorting something while trying to adjust pots or any other thing that goes pop or produces a spark display.