shmups.system11.org

Shmups Forum
 
* FAQ    * Search
 * Register  * Login 
It is currently Sat Dec 05, 2020 10:05 pm View unanswered posts
View active topics



Post new topic Reply to topic  [ 5 posts ] 
Author Message
 Post subject: RGB Modding of a 2005 Sanyo CRT TV. Is it possible?
PostPosted: Tue Apr 14, 2020 9:50 pm 



Joined: 14 Apr 2020
Posts: 2
Hi,

I have bought a 19" CRT TV to fit into my late 80s arcade cabinet. I aim at doing an RGB mod and I want to know if this is doable.

I have some limited knowledge in electronics (although I managed to repair my coffee machine PCB by replacing a dead resistor). I have done a ot of research on the web and it seems I should not have much hope. But I wanted to make sure.

Model is Sanyo ds19204, made in 2005.

I opened the TV (safely), discharge and unmount the PCB. BElow is the picture of the chipset

Image

The big chip (IC101) is Sanyo LA76843M 80 pins. I could not find the datasheet on the web. If anyone has a datasheet that could do, I am interested.
The other chips (IC801) is S031 AVC084 51K9 (I found the datasheet on the web but the chip looks different with many more pins, so not much success here again.)

I am afraid this TV has no OSD chip I can bypass and as I think the OSD is integrated in the 80 pin. But before I seek for another 19" CRT TV I wanted to make sure. If there is any way I can mod this TV, I am willing to give it a go.

Thx for you help.


Top
 Offline Profile  
 
 Post subject: Re: RGB Modding of a 2005 Sanyo CRT TV. Is it possible?
PostPosted: Thu Apr 16, 2020 6:03 pm 



Joined: 08 May 2018
Posts: 93
Location: Denmark
Manualslib seem to have the service manual. According to that IC801 sends OSD RGB out from pin 22 (blanking), 21 (B), 20 (G), 19(R) to IC101 pin 15 (blanking), 14 (B), 13 (G), 12 (R).
Blanking goes through R846 (10K), RGB goes through 6.8K R849, R847, R848 respectively. So it seems a candidate for an OSD mux, unless the RGB are digital, but I wouldn't think so given its internal block that mentions amplification and brightness stuff.
_________________
www.immerhax.com


Top
 Offline Profile  
 
 Post subject: Re: RGB Modding of a 2005 Sanyo CRT TV. Is it possible?
PostPosted: Sun Apr 26, 2020 5:00 am 



Joined: 13 Apr 2020
Posts: 1
Thanks very much for the information. I enlarged the PCB board drawing and marked the RGB and blank lines path. I will try to post a scan of my PCB markup

I followed the "8-Bit Guy" thread, in which it is mentioned about setting up the voltage divider.

So I had to find the resistors connected to ground. I believe they are R842/R843/R844 (interestingly I found the information in the DS19330 chassis service manual as those resistors are not indicated in the DS19204 service manual). Their capacity is 820 ohms.

I used the spreadsheet in the thread and the calculated a resistance of 300ohms to be added.

Now my last difficulty (if everything I mentioned before is correct), is to insert those resistances. I don't know how I can unsolder those tiny ground resistors. I wonder what is the best approach. Appreciate anybody's opinion.


Thx!


Top
 Offline Profile  
 
 Post subject: Re: RGB Modding of a 2005 Sanyo CRT TV. Is it possible?
PostPosted: Tue Apr 28, 2020 1:26 am 



Joined: 14 Apr 2020
Posts: 2
Thank you!

I managed to trace down on the PCB drawing the RGB and Sync lines and location of the various resistors.

Initially I wanted to follow the "8-bit guy RGB mod" thread for ground resistor sizing but found out that my PCB has no ground resistor, nor capacitor. It is a Straight line OSD -> Resistor -> Jungle chip input.

1. Does that mean I can inject the VGA signal straight at the jungle chip input and forget about the resistor divider scheme presented in the thread?

2. Do I need to add a 75 ohm resistor and 104 caps?

Thx for your help.


Top
 Offline Profile  
 
 Post subject: Re: RGB Modding of a 2005 Sanyo CRT TV. Is it possible?
PostPosted: Fri Sep 04, 2020 3:27 am 



Joined: 04 Sep 2020
Posts: 1
Curious if you got this working?


Top
 Offline Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 5 posts ] 

All times are UTC


Who is online

Users browsing this forum: Gunstar and 17 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum

Search for:
Jump to:  
Space Pilot 3K template by Jakob Persson
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group