Dokert
Well-known member
Test diodes D601-D604, and see if one of the four are bad.
Sanyo 20EZ HV shutdown...
- Thread starter RetroHacker
- Start date
Test diodes D601-D604, and see if one of the four are bad.
Zork2
New member
Forward voltage running about .5v on each, reverse voltage indicating OL!
Dokert
Well-known member
sorry, test them with no power using the diode setting on your meter.
modessitt
Volunteer: Encyclopedia Submission Moderator
From the readings he mentioned, I assumed that's what he did. Remember, the meter sends some voltage through the diode during the diode test.....
Dokert
Well-known member
Got it, didn't read it correctly.
Turn VR301 (Sub-Brightness) all the way to one side and attempt to set the B+. Turn VR301 all the way to the other side and attempt to set B+ if it did not work on first try.
Zork2
New member
Yeah, that was with no power, chassis is on my bench. I will give that a try tonight when I get home from work. You think the 134v B+ and the fact that I have no neck glow are related? Or are we looking at 2 seperate problems here?
At 134 volts, that Sanyo monitor is going into x-ray protection shut-down. Long story short....the flyback is being disabled. IIRC, the heater voltage comes from the flyback. So, no flyback running...no heater voltage.
Edward
Zork2
New member
Hmm makes sence. What is the most common casue for X-ray protection shut down? I think I'm getting HV, the screen has a static "crackle" to it, and when I pull the anode cap, I'm getting a nice pop from the tube discharge?! That mean the flyback is working right? It is a brand new Flyback.....
Dokert
Well-known member
Each make and model is a little different in what causes HV shutdown. In this case it is usually the regulator IC601 or a bad B+ pot.
I suspect that your new fly is working just fine from the sounds of things.
Zork2
New member
Dokert, I adjusted VR301 all the way to one side, attempted to adjust B+ voltage, no change. Adjusted VR301 all the way to the other side, attemped to adjust B+ voltage, again no change, still hovering around 135v.... what next?
Zork2
New member
Not sure if it matters, but I did this with the Degussing coil unplugged? That B+ pot is brand new, so is my IC 601! Very frustrating!
Dokert
Well-known member
Start checking traces for cracked or broken traces. Check continuity from point to point on the traces in the 600 section.
Zork2
New member
DOKERT YOU ARE THE MAN!!! Bad Solder joint on PS601. Oviously cracked away from the board, no conductivity from joint to board. Resoldered. Turned B+ pot down and VR301 down, BINGO!! From that point I was able to get B+ right to 108v. 3 weeks of PURE FRUSTRATION TURNED TO BLISSFULL GLEE!! YAHOOO!!!
I can't believe I missed that before? I have probably spent 10 hours over the past couple weeks looking over every inch of that board, front and back and didn't catch that! I guess when you have a general area to be looking, it really helps! On to my next problem, got DK3 to sync up, but DK would NOT??! Different problem differnt day, different thread. HEY I appologize for completely hijacking this thread, but maybe my problem will help someone else! Thanks to all, and once again Dokert, YOU ROCK!!!
I can't believe I missed that before? I have probably spent 10 hours over the past couple weeks looking over every inch of that board, front and back and didn't catch that! I guess when you have a general area to be looking, it really helps! On to my next problem, got DK3 to sync up, but DK would NOT??! Different problem differnt day, different thread. HEY I appologize for completely hijacking this thread, but maybe my problem will help someone else! Thanks to all, and once again Dokert, YOU ROCK!!!
Dokert
Well-known member
Good deal Zork.
Only kept working with you in this thread in hopes that the others in this thread find it useful.
We can continue in this thread for the OP and others or take it straight back to the OP's problem.
Only kept working with you in this thread in hopes that the others in this thread find it useful.
We can continue in this thread for the OP and others or take it straight back to the OP's problem.
RetroHacker
Well-known member
Well, as an update to my original problem, I replaced the current limiting transistor and still the same problem. Still waiting on my (backorderd) voltage regulator from Bob Roberts.
-Ian
-Ian
spoonman
Active member
So far on the hit list has been:
New Filter Cap
New B+ pot
New voltage regulator
New Flyback
Monitor had been fulled capped less then a year ago and worked fine till my flyback died (does not mean much i guess)
I can get a pic at 106vdc and it has a flag wave to it, i played it for maybe 30 min before the monitor shut off. i have done that test now twice.
My monitor bounces around +- 1vdc and i can get it to over anywhere from 104.9vdc to 106.9 vdc and as i approach 107vdc it will spike to 134vdc and turn the monitor off. So i am able to adjust the B+ with my new pot it is just once it hits around 107 it all goes down hill
Strange things i have noticed are that if i turn the brightness down the B+ reading will go up upwards to 106.9ish and if i turn the brightness way up then the reading will go down to say 103 vdc. The same is true when i adjust the power from the flyback. or when i mix and match.
I went over and made sure all the diodes D601-D604 were reading fine one way. I then went around the 600 series as suggested looking for a break between points but all points passed continuity tests.
I did the same in the area of the flyback i installed as well.
I have another known working chassis coming in the mail but do not really wanna give up on this one.
Whats next?
I noticed with in a short period of time several people on this board have had pretty much the same issues pop up, is it possible that we all ordered from the same bad batch of parts when we started fixing these?
New Filter Cap
New B+ pot
New voltage regulator
New Flyback
Monitor had been fulled capped less then a year ago and worked fine till my flyback died (does not mean much i guess)
I can get a pic at 106vdc and it has a flag wave to it, i played it for maybe 30 min before the monitor shut off. i have done that test now twice.
My monitor bounces around +- 1vdc and i can get it to over anywhere from 104.9vdc to 106.9 vdc and as i approach 107vdc it will spike to 134vdc and turn the monitor off. So i am able to adjust the B+ with my new pot it is just once it hits around 107 it all goes down hill
Strange things i have noticed are that if i turn the brightness down the B+ reading will go up upwards to 106.9ish and if i turn the brightness way up then the reading will go down to say 103 vdc. The same is true when i adjust the power from the flyback. or when i mix and match.
I went over and made sure all the diodes D601-D604 were reading fine one way. I then went around the 600 series as suggested looking for a break between points but all points passed continuity tests.
I did the same in the area of the flyback i installed as well.
I have another known working chassis coming in the mail but do not really wanna give up on this one.
Whats next?
I noticed with in a short period of time several people on this board have had pretty much the same issues pop up, is it possible that we all ordered from the same bad batch of parts when we started fixing these?
Dokert
Well-known member
IMO, it is not bad parts but rather rough handling of the chassis during repairs.
There are 3 brightness pots on a Sanyo 20EZV...
1. Front brightness next to the other adjustment pots
2. Sub brightness in the center of the chassis
3. Main brightness on the fly
Try this out and see what you get... Center all 3 brightness pots, fire it up and adjust your B+ to 108vdc.
spoonman
Active member
It is totally possible i could have rough handled the chassis and not even known it I am just grasping at straws, i am 98% there though 106/108
I see two pots near the middle of the chassis one you turn from the top and one from the side. Which one should i be adjusting and what is a sub brightness? Better question what do both of these pots do?
Dokert
Well-known member
one is h hold, and the other is the sub-brightness
Most people don't even realize that that have rough handled a chassis. It happens a lot of times when replacing the fly. Flexing the chassis just a hair too much can lead to broken/cracked traces.
Most people don't even realize that that have rough handled a chassis. It happens a lot of times when replacing the fly. Flexing the chassis just a hair too much can lead to broken/cracked traces.
spoonman
Active member
Well I out every pot on half way and it just shoots up to 134vdc. i think if i left it for a bit i will be able to go back and plug it back in and it would come one. then i might be able to fine tune adjust
I did not find any broken traces in the 600 series like you mentioned to someone before. Maybe i am not testing it properly or maybe i am missing something
I did not find any broken traces in the 600 series like you mentioned to someone before. Maybe i am not testing it properly or maybe i am missing something
