Hitachi CPT-1455 RGB mod

[vol.2]

Originally Posted by ostlar

You might be right, that's most likely what it's for.

If you are interested in doing RGB still, it's worth trying to insert directly at the DIN connector before worrying about the s-video stuff as it would less effort.

Did you say this was a hot chassis and that's why you're doing the opto-isolator?

Why would this set have a DIN input on the back if it's a hot chassis?

You need to 1) post the entire power input portion of the schematic here and 2) open up the TV and physically examine the AC input stage.

Judging from the fact that this set has an external DIN connector leading directly to the jungle IC, I would assume that it has a floating ground and is not a hot chassis, and therefore wouldn't need your isolation PCBs.

This needs to be confirmed, but I can't see how they would be able to allow you to plug in and external device if it's a hot chassis.

It might be that you are mixing up the schematics from the RF only set (which would probably be a hot chassis), and the version with a DIN input, which (probably) adds an input transformer.

Need to confirm though. Post the schematic and take some pictures of what is directly on the inside of the set where the power cord goes in.

[ostlar]

Originally Posted by vol.2

Did you say this was a hot chassis and that's why you're doing the opto-isolator?

Why would this set have a DIN input on the back if it's a hot chassis?

My TV is a CPT-1455, and it is a RF only hot chassis. The one with the DIN-connector is the brother, CPT-1444, and I used it as an example. Unfortunately I do not have one.

They are almost identical and have the same chassis number, "NP84CQ/2" for the CPT-1455 and "NP84CQ" for the CPT-1444, but the main difference is the isolation transformer and the DIN-connector on the CPT-1444.

Here's a Reddit thread where they discuss the RGB connector of the big brother CPT-1646, and here's one for the CPT-1644. These also have the same chassis number as 1444 and 1455. They seem to agree that it's a standard RGB signal with composite sync.

The PCBs will arrive next week, and all the other components have just arrived today. Pretty excited to revive this TV with new inputs, and get rid of the RF modulator. If this works, I will attempt it on two other RF only TVs that I have.