Is Toshiba 1843 better than 9929?

[chriszhxi]

Recently I did a full recap (majority with united chemi-con, a couple of Nichicion or Panasonic, best you can get for caps) on 9929 in order to fix some picture issues, after that picture is all good.

I also have another 1843 chassis which I accidentally broke its neckboard nearly into half, I fixed it, but no recap.

I found that 1843 has more color brightness. 1843 literally uses less rgb gains (around 70, where 9929 all max out) to achieve same color brightness, which means it can get more vivid and brighter colors.

I did adjust brightness on flyback on both 9929 and 1843, but that only affects overall brightness not color brightness.

So I'm wondering it's only my chassis or it's common that 1843 is better than 9929?

 

[nem]

Higher heater voltage?

 

[chriszhxi]

Higher heater voltage?

I have no idea what voltage is this, can I adjust it?

 

[nem]

There's a resistor that controls the voltage. It's R901 on the neck board. I'm not sure if there is variation between different models, this is just pure speculation. Is it 2.7 ohm on both? Double check with a meter.

 

[chriszhxi]

There's a resistor that controls the voltage. It's R901 on the neck board. I'm not sure if there is variation between different models, this is just pure speculation. Is it 2.7 ohm on both? Double check with a meter.

Edited:

I found R901 on 1843, the big white cuboid one beside the socket.

Sometimes It's hard to get stable reading from it, could be ranging from 3 to 10 ohm or some high random numbers, but I can get a stable reading around 2.7 ohm out of it.

Could this affects the voltage and causes color brighter?

On 9929 it's R904, its reading is stable at 2.7 ohm sometimes maybe 2.6 or 2.8.

 

[nem]

You would have to remove them to get a proper reading. However, they're pretty heavy duty resistors, so more than likely they're fine and in spec.

One of these chassis has an extended contrast range. It literally will go over 100. However, to access it you will need to modify remote.

See here:

https://forum.arcadeotaku.com/viewtopic.php?p=245159#p245159

 

[chriszhxi]

You would have to remove them to get a proper reading. However, they're pretty heavy duty resistors, so more than likely they're fine and in spec.

One of these chassis has an extended contrast range. It literally will go over 100. However, to access it you will need to modify remote.

See here:

https://forum.arcadeotaku.com/viewtopic.php?p=245159#p245159

I have the extended remote board.

I tried adjusting contrast on 9929, but can't get the same feeling.

1843 have those highlight spots, kinda like HDR peak brightness area on modern monitors.

But 1843 has one small issue that is some kind of jitter, or shaking sometimes, very subtle, you have to pay attention to notice it.

9929 also had this after recap, I adjusted the focus knob on neck board, the jitter is gone. But no matter how I adjust the focus knob on 1843, the jitter is still there.

Do you have any idea how to get rid of the jitter?

 

[nem]

Not all extended remotes have the extra contrast mod. Which one do you have? Can you make adjustments over 100 for contrast and brightness?

No ideas on the jitter, sorry.

 

[chriszhxi]

Not all extended remotes have the extra contrast mod. Which one do you have? Can you make adjustments over 100 for contrast and brightness?

No ideas on the jitter, sorry.

I can go over 100, just tried set contrast to 136, the highlights parts look kinda like 1843 now, but overall colors look heavy and harsh, while on 1843 colors look more gentle. I tried tweak with rgb gains and cut, also brightness, just can't get the same highlights with gentle colors on 9929.

Guess I just have to take it. Thanks for your help.

 

[BuddyC]

I have the same experience with PD9929 VS PD1843.
I tried every trick in my “calibration book”, but PD1843 just produced a better overall picture every time. Even hooked up a 1843 chassis on a Tosh-tube that used a stock 9929 chassis and the 1843 was a clear winner.
The PD2367 also produces a hell of a picture, but my favorite is easily 1843.
Just my 2 cents.

 

[BuddyC]

Do you have any idea how to get rid of the jitter?

I did a complete reflow of the neck board and the jitter went away on my PD1843. Board looked clean but probably had a cold solder joint or 2.
No issues since then.

 

[chriszhxi]

I did a complete reflow of the neck board and the jitter went away on my PD1843. Board looked clean but probably had a cold solder joint or 2.
No issues since then.

I will give it a shot, thanks for the hint.

 

[dewmansnk]

• PB9929
  • Microcontroller-TMP87CK38N
  • Video Amp-M52337SP
  • Deflection IC - NEC C1883CT (NEC uPC 1883)
• PD1843
  • Microcontroller-TMP87CM38N-5NF5
  • Video Amp-LM1269NA
  • Deflection IC - NEC C1888FCT (NEC uPC 1888 )
• PD2367
  • Microcontroller-TMP87CM38NG
  • Video Amp-LM1269NA
  • Deflection IC - NEC C1888FCT (NEC uPC 1888 )

(https://www.arcade-projects.com/threads/toshiba-tri-sync-pbxx-pdxx-pexx-notes-mods.21081/)

The PB9929 uses an older video and deflection IC, the PD1843 and PD2367 use the same video amp and deflection ICs - so, yes I have found the PD1843 and PD2367 to be better than the PB9929 in my testing as well.

 

[BuddyC]

• PB9929
  • Microcontroller-TMP87CK38N
  • Video Amp-M52337SP
  • Deflection IC - NEC C1883CT (NEC uPC 1883)
• PD1843
  • Microcontroller-TMP87CM38N-5NF5
  • Video Amp-LM1269NA
  • Deflection IC - NEC C1888FCT (NEC uPC 1888 )
• PD2367
  • Microcontroller-TMP87CM38NG
  • Video Amp-LM1269NA
  • Deflection IC - NEC C1888FCT (NEC uPC 1888 )

(https://www.arcade-projects.com/threads/toshiba-tri-sync-pbxx-pdxx-pexx-notes-mods.21081/)

The PB9929 uses an older video and deflection IC, the PD1843 and PD2367 use the same video amp and deflection ICs - so, yes I have found the PD1843 and PD2367 to be better than the PB9929 in my testing as well.

Awesome info! Thanks!