Modding the JVC TM-A13SU Monitor

[Bryan]

Cool. Glad to hear it. I'll make a tested elf file when I get a chance.

[Bryan]

I've been experimenting with service mode settings to improve this monitor's performance with Atari video. So far, I've only tested NTSC settings.

 

CONTROL BLOCK:

40 - Color Trap Q = 0 (1.0) reduces chroma banding in Composite video

42 - Color Trap F0 = 0 (-100KHz) reducing the frequency a touch improved the picture on my setup. I'd try all the settings on a blue BASIC screen to see which one looks best.

44 - Chroma TOF = 0 (off) Chroma Take-Off Filter control. The picture is definitely better with it off.

[+Stephen]

I've been experimenting with service mode settings to improve this monitor's performance with Atari video. So far, I've only tested NTSC settings.

 

CONTROL BLOCK:

40 - Color Trap Q = 0 (1.0) reduces chroma banding in Composite video

42 - Color Trap F0 = 0 (-100KHz) reducing the frequency a touch improved the picture on my setup. I'd try all the settings on a blue BASIC screen to see which one looks best.

44 - Chroma TOF = 0 (off) Chroma Take-Off Filter control. The picture is definitely better with it off.

You're really making me want to buy one of these monitors.

[Miner 2049er]

Wow....Looks like I've got some work to do... I just picked up 3 of these suckers in the last couple months. Two I can mess around with, but I've got 1 brand new unopened that i'd like to keep as a backup

[Bryan]

There are better pro monitors out there, after all this is a general purpose model with a standard resolution tube. But, it's got a great picture and it the best choice for that classic '80s monitor feel. I have two and keep wanting to bid on more for some reason.

[erichenneke]

There are better pro monitors out there, after all this is a general purpose model with a standard resolution tube. But, it's got a great picture and it the best choice for that classic '80s monitor feel. I have two and keep wanting to bid on more for some reason.

This is terrific. I think I am going to buy one of these and go this approach!

 

So stop driving up the prices on eBay! Ha!

[rmzalbar]

Hi, are there any updates to the code for this project? I was thinking of doing one for the monitor I have. I already have a TL866 which I use to program eproms, but haven't tried doing a microcontroller yet. What did MitchSchaft end up having to do to resolve the issue and finish the project? Thanks!

[MitchSchaft]

He shipped me a chip with the program already on it. I couldn't figure out the bit settings.

[rmzalbar]

I've sent a PM to Bryan. I would like to sort out a TL866 method if possible - and if we do, I can add a how-to here.

[MitchSchaft]

That would cool. I couldn't get it to work right with my TL866a. I wonder if my new TL866ii plus is any different

Edited December 17, 2019 by MitchSchaft

[rmzalbar]

I did read that there were some issues with ATTiny fuse bit setting/reading protocol in some versions of MiniPro a couple years back,  so maybe that was your issue and it could be fixed now. I'm trying with MiniPro 6.85. I think all I need to know are the correct settings (or the fuse bytes) to give it a try.

 

EDIT: based on Bryan's description of CPU flags, I think it's this:

"Brown-out at 2.7V and Internal RC @8MHz 6CK/14CK + 64ms"

Running that through this calculator:

http://eleccelerator.com/fusecalc/fusecalc.php?chip=attiny45&LOW=E1&HIGH=DF&EXTENDED=FF&LOCKBIT=FF

 

 - Low Byte: 0xE2 (set SUT0, CKSEL3, CKSEL2, CKSEL0)

 - High Byte: 0xDD (set SPIEN, BODLEVEL1=0)

 - Extended: 0xFF (no settings)

 - Lock: 0xFF (no settings.. no need to lock it, of course!)

 

Edited December 19, 2019 by rmzalbar
add screenshot and fusebit info

[rmzalbar]

OK, I just finished installing the mod, and it works!!

 

I'm uploading a project file for MiniPro v6.85, for use with the TL866. Loading this project will import the program data and the correct fuse byte settings. All you need to do is pop in a chip and hit Program.

 

If you're doing this from scratch with Bryan's file:

 - Launch MiniPro and select ATTINY45 as the program target.

 - Load the default\jvc_mod.hex file as File Format INTEL HEX and To Region CODE MEMORY

 - On the right side of the window, under Buff. Select click Config

 - Set the following checkboxes:

      Low Byte: 0xE2 (check SUT0, CKSEL3, CKSEL2, CKSEL0)

      High Byte: 0xDD (check SPIEN, BODLEVEL1)

      Extended: 0xFF (no settings)

      Lock: 0xFF (no settings)

 

 - Drop in your ATTINY45 chip and click Program. That's it. Don't try to use the .ELF file, MiniPro doesn't interpret it correctly; the result is garbled data and settings.

 

Thank you Bryan for creating this awesome thing, and also MitchSchaft for showing his work (I used your method of a breakout board on top, except that I routed the wires around to the underside of the board for easier soldering).

jvc_mod_MiniPro.zip