20EZ : B+ 163v!

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Hi,
I checked the forums for a solution and went through all the suggested solutions to no avail, (still need to check the horizontal pot).

Here's the rundown of the current situation.

When I got the game, the monitor (20EZ) was dead. I performed a completed cap job and also replaced the HVT.

When I fired it up, I had a display but the B+ was at 114v. The pot was glued so I shut it down and cleaned it up. Then when I powered it back up, the voltage jumped right up and could not be controlled by the pot. Tested the pot and one leg was open so replaced the pot with a new one.

Then tried again. Voltage shot right up and still could no be controlled by the new pot.

Ordered (from Buffett), received and installed a new IC601 and tried again. Voltage shot right up!

Even though TR901 tested good, I replaced that and tried again. Voltage shot right up!

Checked for cold solder / cracked traces and none found.

I took a reading at the base of TR901 and received 163v, I do not know what that is supposed to be but it seems to be high.

Can anyone tell me what that reading should be (base of TR901)?

Any ideas of how to proceed / what to check next

Thanks
Jeff
 
Have you replaced the electrolytics in the VREG circuit? Bob's base kit I don't believe contains those caps, not sure on the deluxe. If you ordered from pretty much anyone else you should have replaced it. 300mA fuse still intact? It sounds like you have replaced all of the critical parts (2SD1090 and LA5112N, POT) Might be time to just start voltage probing various nodes to see whats going on. Would be worth checking the base of the d1090 and the other side of the 30 ohm resistor that drives the base.
 
I'll echo what Ian said.... leave no electrolytic unreplaced in the B+ section. I made the mistake of using an older (less complete) kit... and a small (seeminly insignificant) 1uF cap (if memory serves me correct), was borderline (tested ESR good when cold), and I had all sorts of voltage reg problems (low though, not high) after it was on for 20 or so seconds.

If you've done all the caps, something seems fishy about the old pot/new pot change... have you traced the pot traces back to their destinations, and used a DVM to see that the center to left and center to right resistances vary when you move the pot ?

Good luck, I know my little 1uF cap kept me hunting on and off for about 3 weeks. I now have little faith in any old caps... although the really large ones generally survive.... but if I can, I replace every cap now after that little 1uF one stole hours of my life :)
 
Hey Guys,
Thanks for the suggestions....

I did in fact purchase IC601 from Buffett, I wanted to be sure that I got a genuine part....

ALL electrolytic caps were replaced - All of them......

After changing the pot, I did check to be sure that it was functioning correctly and there was change when turned on the one leg.

I took a voltage reading at the base of the 1090 and received +163v and do not know if that is supposed to be that high but I don't think it should be, does anyone have the correct voltage what it supposed to be???? I will check that 30 ohm resistor and see what it reads.....

Thanks
Jeff
 
The base should be 109ish
measure the emitter too since the base should always be .7-1.4V above the collector. it sounds like there is 1, no load at all on the supply to bring it down, or 2, the IC is bad, or 3, that 30 ohm resistor is somehow bad.
 
OK, I got a copy of the schems with voltages shown and then realized that I had been using the incorrect Iso X-former. It was putting out 127vac.
I pulled the powerbrick from the game and using that got 110vac to the monitor and have the following voltages:
From the 1090:
B= 141v
C= 150v
E= 142v
The HV runs up to about 26kV and then shuts down.....
Using the B+ adj pot while in shutdown, I can modulate the voltage from 142v to 145v
I tested R612 (33 ohms) and although it tested good, I replaced it and still NG........
 
110V is still 10V too high for the 20EZ.

It may be able to get setup to run on 110V ok, I'll let anyone experienced with that comment.

If not, you'll want to pick up a transformer from any of the nintendo games.... they'll take and give you the 100V the monitors wants.
 
I used the powerbrick from the game that the monitor came from.
It is a Pacmania game and it had worked in that cab since it was built....
I carefully inspected all caps pulled and compared them to my parts sheet during the rebuild process and all were as expected, none were subs.....
There were no modifications to that monitor and it had run on that voltage for decades.
Of course, with my luck, once it was rebuilt, it now wants the 100v and will not settle for anything less........(or more for that matter!)
 
I believe you have a Sanyo EZY monitor it is made to run on 110-120volt.. Those came in dragon spirt arcades, pacmania, I here dig dug and Crystal castles. They are intended for American ISO 110-120v. The Nintendo cabs were the lower 100 volt ISO transformers..

Correct me if I'm wrong here but pretty sure as I've seen them in many Atari cabs, and I own a shit ton of nintendos with 20 ezv models

http://forums.arcade-museum.com/showthread.php?t=296292


http://arcarc.xmission.com/PDF_Monitors/Atari Monitor TM-311 1st Printing Sanyo EZV 19in .pdf[/QUOTE]

Manual and above link

Sanyo 20-EZY. Almost the same as the Z, but non-inverted video, no flyback cage, and no sound amp.

The easiest way to tell the difference, the filter cap. EZV's use a 470uf at 160 volts.......the EZY uses a 330uf at 200 volts.
 
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I guess mine is the 20EZV as it has the filter cap at 470uF 160v... also has the amp, HVT cage and inverter PCB......
The spec sheet (thanks for the link) states 100v (+10%) so I guess I am within parameters..... but why the heck does it keep shutting down?!?!?

Like I said, once I rebuilt it - it worked, just that the B+ was at 114v....... Once I replaced the pot - BAM!

I checked 10X and the pot (Bourns) is stamped 502 which equals 5K...

Thanks again for the info....
Jeff
 
Something weird is going on here.......

I hooked up the monitor to my variac and had to supply 80vac to the chassis to get a reading of 98vdc on the B+ and the pot only had a range of 97.3 - 98.0 vdc.....

So it looks like something is bumping up the voltage a bit!

I adjusted the screen with a test pattern going to the chassis and only got a green line and raster which did not change when I changed the input from the pattern generator. (see attached)

Any ideas of what is going on here!?!?!?!!?

Thanks
Jeff
 

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All I see in that circuit is an inductor and diodes, I guess I'll pull it apart again and check those out.
 
I checked everything out and it looks like the VR I got might be bad......

There is nothing else left to check - is there>>>>>>>?
 
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