Moon Crest electronics questions

[level42]

And I need two of them, F 4A, for in the fuseholder after the insulation transformer. I can't find them, but at my work they have S 5A. Is it safe to use those instead of the F 4A?

NO !

S are "Slow blow" fuses. The current rate ( >5A in your example) will have to be present for a relatively long time before it blows. If you put it in a spot where a F ( Fast acting) fuse is designed and there is something wrong with the device where the F fuse should blow as fast as possible you will definitly burn some parts on the device because the Slow blow fuse will blow much later, and I mean MUCH later in terms of electronics.....

I've replaced some fuse holders on monitors because I wanted to use Euro sized fuses instead of US sized. The reason is that I have very little problem in "getting" the correct fuses in Euro size.............

[PaulSwan]

Slightly tangential, but when I first ended up with KT-3 monitors to fix (in Quasars), I immediately thought "I know, I can just put an MTC-900 in there instead". Did the wiring and to get the MTC-900 all working nice...

...and then...

...the damn thing wouldn't fit in the cab. The problem was that the metal surround for the monitor in the KT-3 set the CRT recessed from the frame. In the 900 it wasn't recessed in the frame. The back door opening was thus too low to be able to slide in an MTC-900. Ended up undoing it all and then fixing the KT-3 instead 

Thus, I'm interested to know if you are using an MTC-900 frame and if it fits in your cab

I don't know if you can use an MTC-90 yoke with an MTC-900. I've not tried that conversion myself but it's an interesting idea.

Paul.

[ckong]

Well, I will do the monitor swap/repair in two stages. The Moon Crest cab will first get a temporary donor combo, which will be:

a. Kortek/Samsung combo that I recently pulled out of a cab, working
b. the MTC900/? combo which is at the moment in my Zaccaria Vanguard, working
c. a NOS WG combo

I decided not yet which one I will use, and it will be a temporary thing, I want the original MTC90/211X combo to be repaired and then be placed back in the Moon Crest.

Digimon came up with Winnie, a German Goeroe on everything Analoque and a master in repairing (old) monitor chassis. I haven´t contacted him yet, but I hope that he can and want to repair it.

It will be great to have the Moon Crest all original.

[PaulSwan]

Yeah, if you can get the 90 working it would, of course, be best Can't wait to see what version of the Moon Cresta ROMS you're board has - are we taking bets on a (c) Zaccaria logo? My money is on no (c) 

[level42]

Yeah, I'd like to see the PDF too...you know my e-mail address

[ckong]

Yeah, I'd like to see the PDF too...you know my e-mail address

I did e-mail the PDF file to Arcade Archive, as you suggested, but watch your mailbox. If others want it, shoot me a PM with your e-mail adress (no, I don´t have dropbox or something like that and my preferred online storage site was taken down a few months ago).

[Etienne MacGyver]

One final question: everyring in the cab works on either +5V or +12V, but not the coindoor lights, they work on 6.3V. Why did they do that? Why not use also 5V or 12V for the light bulbs? Because 6.3V was common use?

I can only imagine that they did that because there is a separate pcb which takes care of the credits, and if you look in the schematics, the bulbs are connected there, Question still stands; Why ? Maybe to lower the load on the 5 & 12V lines ?

Anyone ?

[level42]

You don't want lamps in the neatly regulated +5V that powers the game board because it draws a relatively large current and the lamps don't need neatly regulated power. Also, if something shorts in the bulbs ore when changing bulbs you don't want the +5V power circuit to blow because a not working coin door lamp is not a big problem, but a not working game PCB is a big problem ( no income).

Sometimes the 6.3 VAC was also used for the heater of the CRT but that wasn't a good idea for the same reasons above and I think it was only done on very early vectors IIRC.

Also, when making a transformer this is "just another tapping point" and almost doesn't raise the cost of the transformer.

[ckong]

...and then...

...the damn thing wouldn't fit in the cab. The problem was that the metal surround for the monitor in the KT-3 set the CRT recessed from the frame. In the 900 it wasn't recessed in the frame. The back door opening was thus too low to be able to slide in an MTC-900. Ended up undoing it all and then fixing the KT-3 instead 

Thus, I'm interested to know if you are using an MTC-900 frame and if it fits in your cab

Paul.

Indeed. Damn.    The MTC-900 frame doesn't fit in the cab. neither does the Wells Gardner. Too bad. So, it doesn't seem that it will be all that easy to fix the game as I had hoped. I suppose that I will just put the cab aside for some time and let the original chassis/monitor combo be repaired.

I did try the game pcb (blind of course). It is alive. A bit. If I power the game board, i hear a high tone coming from the speaker (so the speaker works!) and the coin counter doesn't credit. when I de-attach the game pcb again, the coin credit works again. 

Unfortunately I don-t have any testing equipment, so I might bring the board to the PCB doctor.