Sanyo DS25530 - Modding Help

[2Beeried]

Good Afternoon,

Wondering if anyone can point me in the correct direction here. Recently picked up a DS25530 that had a broken back plate, which I fixed, but was unable to tell when I purchased it that it was RF-only, as the the input was lost to the inner cavity.

Opening the back up, I have found that it is a hot chassis, so I was going to write off being able to add component or more, until I saw that the board is silkscreened for component. Is this something I can populate and tie back into the boards logic and add component to this TV? I found another Sanyo that I think shares the same board but with the component populated, but I am unsure if it is 1 to 1, it is the DS31650. Any guidance here would be amazing, thank you in advance.

Have a number of pictures on imgur for it: DS25530 Images

and here are the documentations I have found for them:
Google Drive

[vol.2]

Originally Posted by 2Beeried

Is this something I can populate and tie back into the boards logic and add component to this TV? I found another Sanyo that I think shares the same board but with the component populated, but I am unsure if it is 1 to 1, it is the DS31650.

I believe that the unpopulated area looks like it's isolated with optical ICs, so I think it's definitely designed from the factory to have that option.

HOWEVER. You would need to check with the service manual and probably also have the datasheet to the jungle IC (the audio video input/output IC) to

1) confirm that the inputs can be setup without altering the system memory

2) have a complete part list to populate the missing ICs from the PCB

My hunch is that you will not be able to "turn on" the composite inputs because those inputs are enabled by setting up registers in the memory, and that is done in the factory by flashing to an EEPROM on the board that talks to the main video IC and sets up the environment.

In essence, you would have an input with no way of switching to it.

But you can read the service manual to figure that out by finding the main video IC and then locating the datasheet for that IC. In the datasheet, there should be a section on programming the IC from memory, and how to set it up. If that section exists, then it's not going to work.

The other option is that the inputs are set with a switch that changes an enable pin or something like that. So you might be able to fool the set into displaying from the composite inputs if that's the case, but it's very unlikely. The reason they started using EEPROMs and large integrated video ICs has to do with cost reduction of all the old analog parts they used to use.

[2Beeried]

I believe the Jungle is an LA7673, labeled on the schematic as IC101. Now would the Jungle be the main IC or would it be the other one? The other one is an LC8641208, labeled as IC501. The Front IO panel is connected to IC501 from how I read, but the composite video is connected to both, with R-Y, G-Y and B-Y running directly to and directly from IC101. (I have said schematic added to the imgur as a jpg, but also in the google drive as a PDF for ease of use)

On the EEPROM side, if it is controlled by EEPROM, are they able to be translated and modified now-a-days? I have EEPROM flashed in the past from scripts and such, but never had to read, decode and create one myself, so I don't have the faintest idea of how possible this task is, unless I could flash onto it using an image from one that has component with the same board, like the DS31650 if they are using the same everything, with one just having component populated.

[vol.2]

Originally Posted by 2Beeried

I believe the Jungle is an LA7673

Yes that is a jungle IC. You would need the datasheet for that to do anything with this.

On the EEPROM side, if it is controlled by EEPROM, are they able to be translated and modified now-a-days?

Yes, it is possible to flash a new EEPROM and replace the old one with a new set of instructions to adjust the functions, but you would have to both know how to program it (all this information is always included in the jungle IC datasheet) and you would also have to know exactly what you are doing. If you are capable of reverse engineering the TV's EEPROM, there wouldn't be anything I could help with.

As far as I can tell, the datasheet for the LA7673 isn't out there anywhere.

It may be possible that it could be done without messing with a ROM, but I would probably need that datasheet to be sure myself. You might be able to figure it out by writing down on the ICs in the schematic and looking for an ROM attached to the 7673. If there are no ROMs or memory in the set at all, then that would be a more positive indication that it's not necessary.

[jhalphen]

Hi to all,
Hi 2Beeried,

Found these two Jungle chip data sheets LA7672 & LA7674 (not LA7673) but probably quite close.

Personally, i would forget populating a board, optocouplers & E-PROM reprogramming, sounds very Rube-Goldberg to me.
Run the TV through an isolation transformer. The Composite Video Out on the jungle chip (seems to be pin 44 on your Zip schematic).
Looking at LA7674 data sheet, RF Video Composite Out is 44, pin 41 is Ext Video Input and pin 43 is the switch to choose between RF & Composite input. Everything is already built-in!

Best Regards
jhalphen
Paris/France

[Alex KL-1]

jhalphen,
Sounds like a interesting idea.
Generally jungle IC that are separated from the µcontrollers have chances to be "fooled" with new input signals if we cut the internal video coupling and inserts signal here, but it this LA7673 have a pin for select input, like it's cousins, better yet!