Problem Sanyo EZ20 Dead?

[jerryspaghetti]

I have a Junior cab that's showing zero signs of life from the monitor. I have audio from the game but there's no neck glow, no hum and no static from the screen at all.

The two glass fuses are both good and there's no obviously blown or leaking caps and no flyback leakage to note.

I thought it might have been the internal 100v socket but ruled that out as I am getting audio so the sound amp in the monitor must be getting power. I can also adjust the volume.

The neck board is connected well and everything else looks normal in terms of connections. The horizontal test switch is in normal position also.

I'm at a loss to work out what it is without investing in a flyback from the US and a full cap kit but I really don't want to pour money into a monitor that's dead. It has a fair amount of DK Jnr burn too whereas I might pour a bit of money in if the tube was really nice.

Is there anything obvious i'm missing?

 

[K1ngarth3r]

What reading do you have on B+

 

[jerryspaghetti]

What reading do you have on B+

Gonna have to test that, will report back.

 

[jerryspaghetti]

B+ voltage is a big fat zero.
Tried adjusting screen voltage, b+ pot and even horizontal hold on the chassis and no joy.

apart from the sound amp working the screen is the same whether it’s turned on or off! Dead as a dodo 🦤

 

[jerryspaghetti]

Anyone know what the resistance of the horizontal hold pot or if I can take one of the pots from the inverter board and use that as a replacement?

 

[K1ngarth3r]

B+ voltage is a big fat zero.
Tried adjusting screen voltage, b+ pot and even horizontal hold on the chassis and no joy.

apart from the sound amp working the screen is the same whether it’s turned on or off! Dead as a dodo 🦤

Does the 100v plug socket have power?
Is the HOT good?

 

[jerryspaghetti]

Does the 100v plug socket have power?
Is the HOT good?

Yeah, 100v socket is good. Need to check the HOT tonight.

I think i'm going to swap out the horizontal hold pot too as the guy I got it from described problems relating to that area and that it was powering up a few weeks ago.

Unfortunately he had it stored in a place with no power so couldn't show it working before I took it away.

 

[gunblade]

0v on b+ would point towards a blown fuse but depends on where you are reading, there is a mains fuse and a b+ fuse. If a fuse is blown there is a reason for it and depending on which fuse then depends where to look for the culprit
the way you are trying diagnose this is not logical

 

[jerryspaghetti]

0v on b+ would point towards a blown fuse but depends on where you are reading, there is a mains fuse and a b+ fuse. If a fuse is blown there is a reason for it and depending on which fuse then depends where to look for the culprit
the way you are trying diagnose this is not logical

Both the AC and DC fuse are definitely not blown

 

[jerryspaghetti]

I can only assume the current is not making it to the flyback side of the chassis for some reason. Especially as the sound amp is working!

 

[gunblade]

ok where are you reading b+

 

[jerryspaghetti]

ok where are you reading b+

TP91 with the pos and black on the metal frame

Same place i test on my other sanyo monitor

 

[gunblade]

yeah but even a fault in horizontal or flyback will give high b+ not 0
whats the reading both sides of dc b+ fuse

 

[jerryspaghetti]

yeah but even a fault in horizontal or flyback will give high b+ not 0
whats the reading both sides of dc b+ fuse

Good point, I need to check this tonight