Famicom World

Family Computer => Technical & Repair Assistance => Topic started by: Pingaloka on November 27, 2015, 04:11:08 pm

Title: Famicom AV mod, no video output
Post by: Pingaloka on November 27, 2015, 04:11:08 pm
Hi guys, my first post here.
I'm trying to mode an HVC-CPU-GPM-02 Famicom using the following tutorial:

http://jpx72.detailne.sk/modd_files/fc/avmod.htm

But I get no video output.
Here are some pictures of my mod. DO you guys see anything weird?

(https://farm6.staticflickr.com/5649/22730409493_fae023d0ca_b.jpg)
(https://farm6.staticflickr.com/5728/22989674149_9f223ebd98_b.jpg)

Post Merge: November 28, 2015, 12:12:09 am


BTW I'm using a 9v 1200A negative centre Power Supply with an Everdrive cartridge.
The everdrive cartridge seems to work as it has a led that turns on which tells me that the console is also on.
Tried it on my projector as well and nothing. I have Famicom 3 boards, tried doing this mod in all 3 of them and nothing.
I'm thinking and thinking but can't find my error...
Title: Re: Famicom AV mod, no video output
Post by: chowder on November 29, 2015, 12:25:23 am
I don't use that mod, but this part seems strange, unless I'm missing something.

Quote
Next, solder 150R resistor to pin 22 of the PPU (+5V).


Pin 22 is /RST.

This schematic is from the AV Famicom and has always worked for me:

(http://s17.postimg.org/s09x3pvvv/kyuusaku_zps6a57f5ab.jpg) (http://postimg.org/image/s09x3pvvv/)
Title: Re: Famicom AV mod, no video output
Post by: Pingaloka on November 29, 2015, 02:36:27 am
Thanks! I'll try that one!.
One question, C of the trasistor goes to ground right?
Title: Re: Famicom AV mod, no video output
Post by: Arkanix38 on November 29, 2015, 02:54:55 am
Yes, the collector is wired to ground. The electrons need to come from somewhere  ;D
Title: Re: Famicom AV mod, no video output
Post by: Pingaloka on November 29, 2015, 04:16:00 am
One question chowder, no capacitors on the other side of the board so jailbards are reduced.
In the other tutorial I seen 2 x 1uf ceramic capacitors used.
Title: Re: Famicom AV mod, no video output
Post by: chowder on November 29, 2015, 05:23:41 am
Quote from: Pingaloka on November 29, 2015, 04:16:00 am
One question chowder, no capacitors on the other side of the board so jailbards are reduced.
In the other tutorial I seen 2 x 1uf ceramic capacitors used.


I don't bother, they're optional in case the jailbars really annoy you.  I just turn the sharpness on the TV down a little and they're virtually unnoticeable to me :)

Title: Re: Famicom AV mod, no video output
Post by: FAMICOM_87 on November 29, 2015, 08:43:48 am
I used this guide to mode a friend's famicom https://playoffline.wordpress.com/mod/oldfcfba/
and the same as you posted for mine because it is simplest :) http://jpx72.detailne.sk/modd_files/fc/avmod/avmod.png
and it is working , try to bring back the original transistor in place and add one more for the mod
and did not disconnect the original transistor to keep RF functionality :)
an add extra cap for reducing the vertical lines  ;)