Author Topic: Q*bert. A man and his grail... FINISHED !!!  (Read 275698 times)

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Re: Q*bert. A man and his grail...
« Reply #180 on: January 19, 2015, 06:49:20 PM »
BUT.......the panels themselves are actually in good condition, they're not much wider than the T-molding :)


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Re: Q*bert. A man and his grail...
« Reply #181 on: January 19, 2015, 06:54:13 PM »
Here's all the shit that I cut away from the poor patient........ Oh well the swicher may still be working....it _was_ set to 230VAC so the cab obviously _has_ been running in Europe.

By the way, Dirk/Thorsten, that switcher is yours of course  ;D ;D

The wires may still be handy for patch work.....or the copper basket...

Second pic shows the "power" harness. Bad part of the mains cable cut away, but I'll replace that with a European plug/cord. Don't like those weird single insulation US mains cables....not even sure they can handle 230VAC ;)


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Re: Q*bert. A man and his grail...
« Reply #182 on: January 19, 2015, 06:57:14 PM »
Here's another cool part I won't be needing anymore.....I guess there was some awesome lock-bar over the coin door.....with good reason though....of course this coin door has burglar damage too.....I think I haven't seen one coin door in any of my machines without any burglar (attempt) damage....

Oh well, it's nice and heavy, into the "old metal basket" it goes...


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Re: Q*bert. A man and his grail...
« Reply #183 on: January 19, 2015, 06:59:23 PM »
Now, since I was removing the last piece of harness I wondered where the "aux" panel was....I didn't see it. To my surprise however, I felt that there was still a coin-bucket inside the box !

Mmm, let's get it out, maybe it has some nice surprises....

Wahooooo, yes look what's in there :)

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Re: Q*bert. A man and his grail...
« Reply #184 on: January 19, 2015, 07:03:47 PM »
The "aux" panel is there. OK someone removed the volume pot but that won't be a big problem to find a suitable one (I hope).

But there is also a knocker in there !

Now....to be totally honest.......I _know_ that I bought an original Q*bert knocker like AGES ago, with (then) the plan to add it to my MAME cab (Woehahahaha ;))

So I know I have one, but I'm not sure if that is this one.  Maybe I put it in the bucket before.....I really don't remember !!!
I usually do store parts in/on the cab so "they don't get lost"....

OR......this is the original knocker which was removed when they converted the cab......I probably only will know for sure if/when I find the other knocker ;)


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Re: Q*bert. A man and his grail...
« Reply #185 on: January 19, 2015, 07:06:52 PM »
OK. So we know this game was converted at some point in time.

I know....we all hate conversions right ? But then again.....those conversions saved MANY MANY original cabs that else would probably have been demolished.....


SO usually I don't feel very strong about conversions..........but then......I turned the coin-bucket around and saw.........:


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Re: Q*bert. A man and his grail...
« Reply #186 on: January 19, 2015, 07:14:30 PM »
And suddenly the machine felt "dirty"......I mean......this Q*bert....this poor poor Q*bert got converted to one of the games I absolutely loathe.....




Yes buddy, it's sad....but don't dispair !


SO I will be cleaning this cab like nuts !!! ;)

(I swear, even if I have to spray-paint that bucket, that eye-sore _IS_ somehow going to go.....)

On the other side.....this gives me even MORE spirit and motivation to do a great and fast (well relatively) restore on this baby !!! :)
« Last Edit: January 19, 2015, 08:44:57 PM by Level42 »

Etienne MacGyver

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Re: Q*bert. A man and his grail...
« Reply #187 on: January 19, 2015, 09:29:06 PM »
Nice progress !

by the way..



plate or sticker ? dimentions ?  ;)  ::)

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Re: Q*bert. A man and his grail...
« Reply #188 on: January 19, 2015, 09:32:38 PM »
LOL..... I guess there are more for you ;)

Looks like a cardboard/paper. I'll measure when I measure that other stuff in a short while... :)

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Re: Q*bert. A man and his grail...
« Reply #189 on: January 20, 2015, 12:12:22 PM »
Hey Andre, I just had a quick look at the stats and you have surpassed Bruno in the post counts by almost 1000 posts  ;D
- BLANK -

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Re: Q*bert. A man and his grail...
« Reply #190 on: January 20, 2015, 06:37:20 PM »
LOL, not sure If i actually should Be proud of that..... ;)

Wasting my fucking life here and nobody gives a shit about Q*bert ;)

O well....I enjoy doing it so...

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Re: Q*bert. A man and his grail...
« Reply #191 on: January 20, 2015, 07:32:02 PM »
Yesterday evening late/this morning early I decided to check the power section. I had picked up the PSU board from the storage before...however I couldn't find the filter board. In fact I doubted ever seeing one and after I checked my PMs on KLOV it became clear to me that I declined it. I was asked 40 dollars for a fucking board with some pins and louzy useless components and I couldn't jusity that (especially since I only had to pay 20 for the PSU board.....I still am amazed about that, same seller but I also got the PCB harness from him which was a bit heftier in price, but the combo was a good deal IMHO.


anywaaaaaaaaayyyyy, no filter board. I know why, I hate filter boards and usually remove them as soon as I see them. However you kinda NEED the filter board on Q*bert because they used  female connectors on both sides 1:1. Well they are almost, but the key pin differs and following that also the pins.....

So there are two solutions:
1) buy filter board.
2) get rid of the filter boards and the plugs and wire all the shit together.

The longer I think about it, the more I lean to doing option 2). OK, it's a lot of work, may not be original and look not so neat.....but I'd remove a whole range of sources for trouble.....all the connectors on both sides and the pins on the board.....

Annnnnyyyyway.....I still wanted to test the PSU board.

I checked all the main important parts, diodes, big important resistors, of course ESR testing the caps everything was just FINE, even the scorched looking resistors.

So I hooked up the power brick, installed the power harness and hooked up the PCB Harness to the PSU board.


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Re: Q*bert. A man and his grail...
« Reply #192 on: January 20, 2015, 07:59:44 PM »
Now of course I had to "bridge" the connectors somehow. I decide to use some wire pieces. Per voltage I only had to use 2 or 3 wires so that would work.

While figuring all these connectors out I noticed that one connector still had 1 small piece of wire attached....it was near where I had soldered two same colored wires together. I already found it a bit weird that both wires were coming from the same direction in the harness so, following the wires, comparing with the schematics and measuring them I found out that the definitely did not belong together. I fixed it all, one new connector needed and I had to extend the wires a bit. Glad I found that before hooking stuff up !

So...
I tested each and every voltage and low and behold....they are all just FINE !!!! :)

That doesn't mean I'm happy with the PSU board though. I noticed that I could wiggle the big caps (they are Sprague brand again) a little bit and it looked like they unsoldered themselves a little bit because of the heat around,maybe I don't know for sure.  At least I reflowed these solderings and no more wiggling.

Also, this board is no different from any other Q*bert PSU board....it has bad burn marks from the over-heating and poorly designed 30V section.

I've done a bit (actually quite a bit) of investigation about this.

The thing is, that according to the schematics, what needs to be done is lower the +48VDC that is coming out of the rectifier bridge into 30VDC for the sound board and knocker. So....they are trying to "get rid of" 18 VDC. Imagine having a 18VDC power supply and "getting rid" of it's entire voltage somehow......mmmm....

They chose the laziest way, a big fat transistor and a zener diode of 30V. The results are pretty fucked up. Not only is the output higher than 30V (about 33,6V as I measured) but also ......lowering such a big amount of volts in this "dumb" way means producing a lot of heat.

Initially I though that the heat was cause by the knocker/sound board drawing a lot of amperes, but the manual says the 30VDC section is designed for just 1,5Amps....which is not that crazy (compare, a regular 7812 can pump out 1A with proper heat-sinking).

Also, EVEN when I had hooked up only the power-brick and PSU board .....and nothing else....so no load.....the resistors and zener diode get CRAZY hot.

So now I'm thinking of a mod to improve this. I hope to come up with a simple solution that at least will not produce so much heat when there is no load at all....

I know people have experimented with 27V and even 24V zener diodes but that doesn't solve the problem at all, in fact it may make it worse as the required voltage drop with those is now 21 or even 24V (half of the original voltage !!!) so the produced heat would INCREASE. The reason they tried these zener diodes is that the voltage of 33,6V is often blamed for destroying the audio amplifier (LM379) on the sound board. These amps are EXPENSIVE to get these days...
The absolute maximum power voltage for the LM379 is 35V, so this is very near it's maximum.

I'm actually not that sure that this voltage is causing the amps to die....since the knocker is also powered by the 30VDC, I wonder what "shock waves" are going on in this voltage when the knocker gets fired (and especially AFTER it gets fired).
I think my new oscilloscope is going to be handy to have a look at what's going on with this.

Especially when people have a knocker without the damping diode (or a defective one) there will be some nice peaks in this voltage I'm sure.....

Also still have to measure how much amps the sound board uses (haven't hooked it up yet)...

OK if you've read my last two posts entirely you deserve a  :spaceace:

If you also understand what I'm babbling about you deserve :spaceace: :spaceace: :spaceace:
« Last Edit: January 20, 2015, 08:11:22 PM by Level42 »

Etienne MacGyver

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Re: Q*bert. A man and his grail...
« Reply #193 on: January 20, 2015, 08:35:45 PM »
Cool, i just earned 4 x  :spaceace:  ;D

Its a interesting read, thanks for the detailled info man !


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Re: Q*bert. A man and his grail...
« Reply #194 on: January 20, 2015, 09:38:30 PM »
+1!
Love all the details and explanations, the 4x  :spaceace: should go to you!