Monitor Question

[Belike]

Small update:
I used this great stuff on Cab.no.2 Phoenix's tube twice and after some nice fireworks in the neck, the screen became much better:




I also investigated that screen shaking, replaced the chassis and the psu from a similar working Zaccaria cab, but nothing changed.
Hmmm, what else can it be?
My old friend's first thought was also psu and he was not too far, because it was caused buy this good old fan

I disconnected it and there is no shaking anymore.
The vertical strips are still there for about 2 minutes after switching on, so I will surely have to replace some caps.

[Superully]

cool, you're getting better by the minute, bela. obviously it's worthwhile having a guy around who knows his business and who can teach you stuff!

[Belike]

obviously it's worthwhile having a guy around who knows his business and who can teach you stuff!

That's right, I should be a collector with about 20 non-working cabs without my old friend.

[Etienne MacGyver]

My old friend's first thought was also psu and he was not too far, because it was caused buy this good old fan

I disconnected it and there is no shaking anymore.

Thanks for that tip, i am going to try that too in my CK, it has shaky picture too (well more whobbeling) but it looks like the rythm of the 50 hz AC from the 220v of the fan, so i guess i have the same problem.

its worth a try, and it defenetly makes the cab more quiet  
that fan is noisy as hell  

that sucker looks like they took it straight out of a refrigerator  


but do place another fan over that big heatsink, the 7805 is cooking that without the fan.. (and maybe a smallone on the other two heatsinks)
(it was disconnected in the cab from the raiders of the lost zacc pickup, and it was extremely hot....

and you know what extremely hot means..  NOT good !  

Or replace it with a switcher...
nah, better not, we like original old hardware here  

[Belike]

Thanks for your advises Etienne, I will try to clean and repair that original fan first, I hope it will solve the problem.

[Etienne MacGyver]

mostlikely will cleaning not solve that issue since i think its interference from the 220volt line..

you can however try to "move" the cable to another location to see if it makes difference..

i remember the cab from gyruss (donkey kong)  gave strange image, and that turned out to be the stepdownconverter that was "too close to the cab" / "in the wrong area", which caused interference on the screen, we moved it a bit and the screen was perfect

EDIT:
If i got the same issue (and fix by disconnecting the fan) i might try to put this between the mains and the fan:



If it works, i have a few of those here lying around that i can bring to eurocade 

reminder to myself: create a "shoppinglist" of items to bring to eurocade for variouse people 

[level42]

The shaking is caused by the magnetic field from the fan (which is simply an electrical motor of course.) It looks like the "box" around it is all metal ?

If so check if it is still connected to ground by a wire. That metal box acts as a Faraday cage. A cage like that keeps all the electro-magnetic fields inside.
However, if the grounding is gone or bad it won't work anymore...


You also seriously need to clean that grill because it blocks the air-flow quite a bit...might be worth looking for a proper fan-guard or a wire mesh with bigger holes...it is SO much covering...

[Robinholland]

Thanks for that tip about the fan  
My Kong Junior cab is now also fixed from the shake picture  
Thanks !

[Etienne MacGyver]

have not thought of that andre, good tip too!

The fancage is total metal in the zacc's

[Belike]

Maybe we can check this theory with putting some kind of material between the fan and the pcb, that blocks the magnetic field.

[level42]

Maybe we can check this theory with putting some kind of material between the fan and the pcb, that blocks the magnetic field.

No. Because the trick is
1) the box shape. It has to be encapsulated totally (bottom side open is OK)
2) it needs to be grounded for it to work right.

[Etienne MacGyver]

nice, but there is no back on this cage, the opposite side of the grill is totally open...

dont know if that is a big deal since that is pointing to the wood of the cab, and not to the PCB, so it might just wave in that direction then..


here a pic from the manual:

[level42]

Doesn't look like a problem to me.

The magnetic fields is probably not causing much troubles for the (game) PCB, but for the monitor itself.

The magnetic fields influence that of the yoke on the CRT. Those should be "kept apart".

Man, that's a weird fan by the way !!!!

It looks like it has a separate motor (on the lower side) that is mechanically coupled to the fan itself. You might have better results with a more modern axial fan (modern fans have the fan itself as the rotor of the motor). Note that it is indicated at 115V AC (pretty weird for a Euro cab).

By the way, pretty bad design they needed a fan for that power supply....Normally I am 100% for originality, but if fans can be avoided.....(who likes the noise ?). You could think about installing a modern switching power supply. That way you can forget about the fan.....

[Etienne MacGyver]

its on the same line as the monitor as far as i remember, which also needs 110 volts..

maybe thats the problem ? 

[level42]

Well, it has always been on the same lines...so that can hardly be the problem UNLESS there is something like a filter capacitor across the motor of the fan that has gone bad...or the motor itself...