MS8-18A ''H-Size'' Pot broken

[PrincessPrinPrin]

you need a kit like this:

https://www.ebay.com/itm/192292362218

I'm sure you can find one locally but I don't know what they are called in French. Better ask in some French forum. Note that some of those kits are useless as they don't have hex tools.

Again I suggest that you first remove the core with a metal hex key if you have a set of those. The core should be about 25mm long:

Immagine.jpg

[erzane]

Thanks for your link about toolkit

1. Pls where did you get this plastic exagonal extension? Im' really interested on it. This would be the tool I need.

This seems to be a part of the coil and made to set/drive the core. On this chassis (Sanwa PM1730/6), it seems to be present. It's going a little bit out from the pipe, still has the thread allowing to set the core but d0n't have the same head as yours.


2. Btw, I already have a metalic hextool kit of many sizes. I tryed to use them but nor it's to thin (2,5mm), nor it's to thick (3mm) and it goes across the core, through the other side. I didn't succeed to make any rotation of it (and I think it is really unable to be extracted without breakin' it). I can clearely see the exagonal form of the core trough the pipe. Angles are sharp enough to be rotated but I need the good extension tool. As basis, the pot who drove the core was metalic in my coil, and this is the pot I found totaly desintegrated and in many pieces (as you can see on pic). Anyway, the core is still intact.

In the case I didn't get what you're trying to explane to me about the ''core'':
perhaps the core you're talking about isn't the exagonal hole inside the pipe, but the thread of your hexagonal plastic extension. If yes, this part is the desintegrated one, and was smaller.

[PrincessPrinPrin]

The threaded thing with empty hex hole throughout is the core. I've found the plastic tool in my pic above in some old TV or monitor. A 2.5mm hex key is a bit loose but works for me. Maybe you should try from the other side and yes that would require you to desolder the coil from the chassis:

Immagine2.jpg

[erzane]

Do you want I try to extract the core from the back and replace it by another one?

[nem]

If it's broken, yes.

[cools]

Wrap your hex key in something thin to bulk it up slightly for a better fit. Paper or (clear, ordinary) tape should do.

[erzane]

I already did it with tape but no way. I thought about some very hard glue but I should wait for my order first. I bought some plastic trim tools. We'll see what I can do with them.

>PrincessPrinPrin: would you sell yout grey tool you showed to me above?

Another thing: is the ''low/high'' jumper for switch from 15 to 24?

[nem]

Yes.

[erzane]

So the only way to set the width is the coil. It certainly should give me a good enlargement because on some others chassis there is a ''wide/narrow'' jumper which not exists on mine.
Grantspain told me ''width coil will only give about 3 cms adjustment. the jumper will give more'' but I don't have any other jumper except the ''reverse/normal'' one.

Other thing. I can clearly see the threads on the pipe on my coil. It means at basis there was a threaded core but the last owner should broke it/took it off. I checked some other coils and all them have a threaded core with an hex hole at the end. So my coil seems not to be broken, only this threaded core is missing.

[grantspain]

yes it does have a width jumper, you are not looking the correct place- its the other side of the heatshield from the frequency headers

[grantspain]

20130105190456-maldoror68-manual-nanao.png

[erzane]

Thanks for that info
Yes I saw it, but unfortunately jumper looks to be already on ''wide''. Now I know why MVS games looks so wide. But another game (acrobat mission) looks so small, I really need more h.size for that game...

[grantspain]

not good monitor for swapping games unfortunately

[erzane]

not good monitor for swapping games unfortunately

True. But the good point is like this I can really play a one and only game for real

[PrincessPrinPrin]

Monitors of that age generally don't have a handy pot for width adjustment, just a coil. Even American monitors like Wells Gardner are like this, up to the K7000 series at least.

Other thing. I can clearly see the threads on the pipe on my coil. It means at basis there was a threaded core but the last owner should broke it/took it off. I checked some other coils and all them have a threaded core with an hex hole at the end. So my coil seems not to be broken, only this threaded core is missing.

Your pics show that there is a ferrite core in the coil. It's just not sure if it's intact (whole length) or snapped. The core works like a screw: the more you turn it the more it goes in so the fact that on another chassis it sticks out more doesn't mean anything. That's why I was suggesting to take it out, so that you could check it's length.

[erzane]

Here is the max H.Size I can get on that UPL game, and my jumper is sat on ''wide''. I can fill the vertical empty place, but not the horizontal one:


When I tryed to set the H.Size again across the coil, inside the pipe the plasitc of my screwdriver litteraly melt/burst... I know now why the core is metalic. He has to support high temperature:


Somebody wants to give me those two brand new cores. He told me: ''They mesures 236 to 240 thousandths which is 6mm'':


I'm wondering about this now. Since I don't want to take the coil off (disoldier) yet. There will be still no head to turn the actual core. They will be only two cores close to eachothers but no mecanical rotation though... Perhaps I didn't really get how to make it..