Dragon's Lair Fans - Arcade Lifestyle

General Chat => Technical Area => Topic started by: ckong on September 07, 2017, 07:47:17 AM

Title: Zaccaria Power board issue -5V too low
Post by: ckong on September 07, 2017, 07:47:17 AM

Guys, who knows how to regulate the 5V on the Zaccaria Power board, or how to modify the board so that I will be able to regulate it. The attached pictures show the one in my Moon Crest and it is only spitting out about 4.35V, sometimes even less, and Moon Crest doesn't like it (glitches on the screen etc.).

Title: Re: Zaccaria Power board issue -5V too low
Post by: italiandoh on September 07, 2017, 08:48:16 PM

I don't have the schematics, but judging from the pics you provided, it looks like the voltage regulation pot has been replaced by a fixed value resistor (see that circular spot with a 'T' nearby). I guess T stands for trimmer. Anyway, I would do a recap and see what happens before trying the mod.

Matteo

Title: Re: Zaccaria Power board issue -5V too low
Post by: ckong on September 07, 2017, 11:05:37 PM

OK, that makes sense. I believe the power board on the Crazy Kong cab also had this resistor and Etiènne 'fixed' it by replacing it for a pod. Will check that out. Thanks for pointing me in that direction.  :)

Title: Re: Zaccaria Power board issue -5V too low
Post by: Digimon on September 08, 2017, 12:16:07 AM

I always recap the PSU, and add a trimmer like Paul:

http://www.zzzaccaria.com/ZaxxonRestoration.htm

Title: Re: Zaccaria Power board issue -5V too low
Post by: Belike on September 08, 2017, 08:58:24 AM

Quote from: Digimon on September 08, 2017, 12:16:07 AM

I always recap the PSU, and add a trimmer like Paul:

http://www.zzzaccaria.com/ZaxxonRestoration.htm

Absolutely +1 ;D
(http://www.zzzaccaria.com/images/Projects/ZaxxonRestoration/PV/SAM_3667w.JPG)

Title: Re: Zaccaria Power board issue -5V too low
Post by: Etienne MacGyver on September 08, 2017, 09:12:14 AM

I was going to say, Check the inside your CK ;-)

Click here to go to the page of my modification and value of the pot (https://www.dragonslairfans.com/smfor/index.php?topic=2054.msg24140#msg24140)

Title: Re: Zaccaria Power board issue -5V too low
Post by: ckong on September 08, 2017, 11:03:38 AM

Quote from: Belike on September 08, 2017, 08:58:24 AM

Absolutely +1 ;D
(http://www.zzzaccaria.com/images/Projects/ZaxxonRestoration/PV/SAM_3667w.JPG)

What type of trimmer is it, Bela? do you have an article number, so that I can order them?

Title: Re: Zaccaria Power board issue -5V too low
Post by: Etienne MacGyver on September 08, 2017, 12:06:57 PM

Its a 47 Ohm pot according to the manual.

Title: Re: Zaccaria Power board issue -5V too low
Post by: Belike on September 08, 2017, 12:41:34 PM

Paul used an 50 Ohm one, I guess it is also ok.
You just have to browse for a 47 or 50 Ohm trimmer potmeter. ;)
Reading that part from Paul's Zaxxon resto would be also useful.

Title: Re: Zaccaria Power board issue -5V too low
Post by: Digimon on September 08, 2017, 04:13:32 PM

I use 50ohm Trimmer.

but I have no order no.;-(

Title: Re: Zaccaria Power board issue -5V too low
Post by: ckong on September 08, 2017, 07:11:49 PM

Thank you all.

Title: Re: Zaccaria Power board issue -5V too low
Post by: ckong on April 14, 2018, 11:59:14 AM

Hi Guys, everything OK?

I finally got some capacitors and a trimmer pot, to solve the 5V issue and do the trimmer pot mod. Anyway, I replaced all caps and now I have a steady 5,27V. Possibly even a bit too high, so getting the trimmer pot installed is not a bad idea.

However, how to install it (I'm terrible at reading electronic schematics)? I've got the trimmer and there are six solder points where I can put the 3 legs (or two) of the trimmer pot, see attached picture. If someone could tell me which of the six points I use for which of the 3 legs of the pot.... that would be helpful (my assumption is A to 1 and B to 2 and forget about C).

I know I have to ditch the resistor.

Title: Re: Zaccaria Power board issue -5V too low
Post by: Digimon on April 14, 2018, 01:02:56 PM

you can do it like this:

(http://www.proe-wildfire.de/1_small.jpg)
(http://www.proe-wildfire.de/2_small.jpg)
(http://www.proe-wildfire.de/3_small.jpg)

Title: Re: Zaccaria Power board issue -5V too low
Post by: ckong on April 14, 2018, 01:33:11 PM

Thx.  :D

And done. Caps replaced and trimmer pot added.